Personnel management in the tourism industry. Features of personnel management at enterprises of the service and tourism industry. The tasks of this work include
Carrying out a planned high-altitude justification
To survey the terrain, in addition to the points of the state geodetic network, a planned and high-altitude geodetic justification is created. Planned survey substantiation of large-scale surveys (1:5,000 - 1:500) are, as a rule, theodolite passages laid between points of the state geodetic network. Theodolite traverses can be closed or open, based on two points with known coordinates. When shooting small areas, it is allowed to lay theodolite passages without linking them to the points of the state geodetic base. Theodolite passages are also laid when measuring architectural structures and serve as a planned justification for detailed measurements of facades and interiors. There are other ways to create a planned geodetic justification: microtriangulation, direct, reverse and combined serifs.
The high-altitude survey substantiation is, as a rule, a leveling path laid along the points of the theodolite traverse.
Task: to master the methodology for creating a planned justification on a construction site, to consolidate the skills of measuring horizontal angles and distances on the ground, to learn how to independently process geodetic measurements and calculate the coordinates of justification points. Instruments and accessories: theodolite, tripod, three sticks, measuring device, pegs for fixing the tops of the move, hammer, logs for measuring horizontal angles and lengths of lines, a microcalculator or tables of increments, coordinates, a form for calculating coordinates, pencils, pens, drawing paper, working notebooks.
Figure 7 - Schemes of planned justification:
a - polygon; b - a move based on one starting point
Prior to the start of work, a schedule for the distribution of duties is drawn up. A sample schedule for a team of 5 students (A, B, C, D, E) in relation to the scheme of moves in Figure 7, and is given in Table 2.
A planned survey justification is created by laying the main and diagonal theodolite passages. The main theodolite traverse rests on two points of the reference geodetic network (see Figure 7, a) or is laid in the form of a closed polygon (Figure 7, b), the points of which
are located approximately along the border of the site.
The move I-VI-V, laid inside the polygon for shooting the situation, is called diagonal. Field geodetic work when creating a survey justification includes:
Reconnaissance (study) of the area;
Measurement of horizontal angles;
Measuring the lengths of the sides;
Calculation of coordinates of points of survey substantiation.
If the theodolite traverse does not rely on the starting points of the senior classes, then
Linking the planned survey justification to the core network.
Table 3 - Schedule of distribution of responsibilities
Site reconnaissance
Reconnaissance serves for the final selection of the position on the terrain of the vertices of the theodolite traverse and for binding the points of the survey justification to the points of the geodetic network.
Reconnaissance is carried out with the direct supervision of the teacher and the participation of all members of the team. One of the vertices of the theodolite traverse is taken as the initial one and fixed with a temporary sign (a metal tube with a diameter of 2–3 cm, a crutch, a wooden peg, etc.). The vertices adjacent to it are chosen in such a way that it is convenient to perform angular and linear measurements, as well as to carry out survey work. There should be good mutual visibility between adjacent peaks and favorable conditions for linear measurements.
To check the visibility on adjacent vertices of the theodolite traverse, sticks are installed.
Visibility between points is considered good if the pole is visible at 3/4 of the height. After visibility is established, the starting point is finally fixed (driven level with the ground), and the reconnaissance process continues, moving to the next point. To facilitate finding the point, it is dug in with a groove. At the same time, different teams use various forms trenches. At the end of the practice, after acceptance by the head of the field part of the work, the pegs are removed from the ground.
It is forbidden to install (fix) points of the traverse on the carriageway or on the paths for pedestrians.
Measurement of horizontal angles
Before starting work, all checks of the theodolite must be performed and the measuring device must be compared.
Usually measure the interior angles of the polygon. If the course is laid clockwise, then the right angles along the course are measured. The reading along the horizontal circle is taken first at the previous and then at the next point. So, at point II, they take a reference to point I, and then to point III. If the course is laid counterclockwise, then the left angles along the course are measured, that is, the readings are first taken for the previous and then for the subsequent currents.
The point above which the theodolite is set to take measurements is called the station. At each station, the theodolite is brought to working position: centered over the top of the corner; bring the vertical axis of the device to a vertical position; prepare the theodolite spotting scope for observation.
Centering the theodolite over the top of the corner is carried out using a plumb or optical plummet. The device is centered more precisely, the shorter the sides of the theodolite traverse. The error m c in measuring the angle for centering can be calculated before the start of measurements by the formula
,
glee where t β - angle measurement error; D is the length of the shortest side of the corner.
Taking the error m c twice less than the error m β and the length of the short side D = 100 m, we get
From this it follows that when working with a theodolite of 30-second accuracy on the sides of the angle D = 100 m, the centering error should not exceed 7 mm. With shorter sides, the centering error should be smaller. Bringing the vertical axis to a vertical position is performed using a cylindrical level and three lifting screws.
After installing the theodolite in the working position, they begin to measure the angles of travel. With two directions at the station, the angles are measured by the method of half steps. If the number of directions is more than two, the method of circular techniques is used.
Differences in the values of the angles in the half-points should not exceed the double precision of the device. The arithmetic mean value of the angle from two half steps is taken as the final result. To orient the traverse lines, as well as to control the measurement of angles
it is advisable to count the magnetic azimuths of the sides of the course using the compass and record them in a journal.
Measuring the sides of a traverse
Measurements of the sides of the theodolite traverse are carried out by sequentially laying a measuring tape across the line. Measuring tapes or tape measures should not deviate from the alignment. To indicate the alignment of the line with a length of more than 150 m, additional poles are installed. Before the measurement, it is necessary to clear the target from foreign objects (stones, blockages, etc.).
Linking the planned justification to the points of the reference geodetic network
In cases where the survey site is remote from the points of the reference geodetic network, additional geodetic measurements are performed to obtain rectangular coordinates of the planned justification points. So, in Figure 6 b, in addition to the internal angles and sides of the main theodolite traverse, two additional angles were measured at points VII and ps 7110, as well as the length of the side ps 7110 - VII.
Processing of measurement results. Computational work begins with a second-hand check of field journals. If this work is not done, then errors in field calculations will be discovered only after the complete processing of the materials, which will entail a redoing of the entire work.
Then, in the journal for measuring horizontal angles, a working diagram of the theodolite traverse is drawn up. The diagram shows the points of the reference geodetic network, the initial directions, vertices and sides of theodolite passages. Starting points and sides are shown in red. The names of the points, the values of the horizontal angles and the lengths of the sides are written on the diagram. For orientation on the diagram, the arrow shows the direction north - south.
Calculation of the coordinates of the vertices of the theodolite traverse is carried out in a special statement (table 4) in the following sequence:
1. From the scheme of the theodolite traverse in column 1 of the sheet, write out the names of the starting points and vertices of the main theodolite traverse, starting from the orientation direction pz 7109-pz 7108 and up to the direction pz 7109-pz 7109, and from the angle measurement journal write out the values in column 2
measured angles and, for control, compare them with the stroke pattern.
From the journal of measurements of lines, the values of horizontal distances d i are written out in column 6 and they are compared for control with the scheme of the theodolite traverse.
2. In column 4, write out the values of the initial directional angles α 7109-7108, and in columns 11 and 12 - the abscissas and ordinates of points 7108 and 7109. Enter the initial data in red.
3. Calculate in column 2 the sum of the measured angles and calculate the angular discrepancy of the stroke
, (5)
where Σβ t is the theoretical sum of the stroke angles, which is calculated by the formulas:
Σβ t \u003d α n - α k + 180 ° (n + 1) - for right corners;
Σβ t \u003d α k - α n + 180 ° (n + 1) - for left corners;
Σβ t \u003d 180 ° (n - 2) - for a closed polygon,
where α n and α to - reference directional angles of the initial and final sides of the course; n is the number of sides of the move.
Table 4 - List of calculations of the coordinates of the vertices of the axis of the main traverse
The discrepancy obtained by formula (5) is compared with the allowable
If the angular discrepancy turned out to be greater than the allowable one, it is necessary to check the calculation of angles a second time in the field book, then check the angles using the magnetic azimuths of the sides of the course, and determine which angles need to be measured again on the ground.
It must be remembered that only gross errors in the measurement of angles can be detected from magnetic azimuths. If the angular discrepancy is less than the allowable one, it is distributed equally to all corners. Correction δ β , which is calculated by the formula
round up to 0.1′.
If f β is not divisible by n without a remainder, then a correction that is large in absolute value is introduced into corners with short sides.
In theodolite traverses of short length, corrections to the measured angles can be entered so that the angles are rounded to whole minutes.
For control, the sum of the corrections is calculated; it must exactly equal the discrepancy taken with the opposite sign.
4. According to the formula
calculate the corrected values of the angles and write them out in column 3 of the statement. The sum of the corrected angles must exactly equal the theoretical sum of the stroke angles.
5. Based on the corrected values of the angles, the directional angles of the sides of the course are calculated:
α i + 1 = α i ± 180° - β - for right angles; (6)
α i + 1 = α i + β ± 180° - for left corners, (7)
Table 5 - Translation of directional angles into rhumbs
where α i and α i + 1 - directional angles of the previous and subsequent sides of the course. Calculations start from the directional angle α n of the original side. In table. 5 is the side pz 7109 - pz 7108.
The example gives the recording order when calculating directional angles using formula (7) for table 2.
The control of the correctness of the calculations is the equality of the calculated and initial values of the final directional angle. In the example under consideration, this value for the side pz 7109 - pz 7108 is equal to α k = 339°03.2′. The directional angles of the sides are written out in column 4.
6. If the increments of coordinates are supposed to be determined using tables, then in column 5 write out the points of the sides.
To determine the name and calculate the rumba, use the data given in table 3.
7. In column 6 of the calculation sheet, the stroke length is calculated
8. Coordinate increments are calculated using the formulas ∆х = dcosα and ∆y = dsinα.
Increments are calculated using a calculator or according to an increment table.
Table 6 - Program for calculating coordinate increments
The sequence of calculating the increments of coordinates on microcalculators of the "Electronics B3-18M" type is shown in Table 6 (for example, the side of the theodolite traverse V-pz 7109 with the values α = 238°24.5" and d = 58.74 m).
Calculations of ∆ x and ∆ y using tables of coordinate increments begin with the design of a special table in a workbook. A sample design is shown in Table 5. The values of ∆ x and ∆ y are given through 1′ for horizontal distances of 10, 20, ..., 90 m. Therefore, the value of d is divided into hundreds, tens, units and fractions of a meter and the appropriate increments are chosen for them rounded to hundredths of a metre, final values
increments of coordinates are found as the sums of the obtained values, rounded to 0.01 m.
The signs of the increment of coordinates depend on the value of the angle α or the name of the rhumb. Thus, ∆х has a positive sign at angles α from 0° to 90° (NE) and from 270° to 360° (NW), and ∆y has a positive sign at angles a from 0 to 180°, i.e. (NE and SE). In all other cases, the increments ∆x and ∆y have a minus sign.
Table 7 - Calculation of increments of coordinates according to tables d = 58.74; r = SW: 58°24′
The increments of coordinates calculated or found from the tables are recorded in columns 7 and 8 of Table 4 with an accuracy of 0.01 m.
To control the increment is calculated twice. It is advisable that students make calculations using various means: tables (Table 7) and microcalculators.
9. Residuals are calculated in increments of coordinates along each axis and compared with acceptable values.
The theoretical sums of increments of coordinates along the axes are
where X k, Y k and X n, Y n are the coordinates of the end and start points of the theodolite traverse, respectively. For a closed theodolite traverse (when X k \u003d X n and Y k \u003d Y n)
As a result of measuring angles and lines, errors occur in the increments of coordinates, under the influence of which
These quantities are called residuals, f x on the x-axis and f y on the y-axis.
Table 8 - List of calculations of the coordinates of the vertices of the diagonal
theodolite traverse
In a theodolite traverse based on two reference points, residuals in increments of coordinates along the axes are calculated by the formulas
The discrepancy in the perimeter, which is determined by the formula
is considered acceptable if it does not exceed 1:2000 of the perimeter R.
10. If the discrepancy in the perimeter is acceptable, then the discrepancies along the axes f x and f y are distributed with the opposite sign to all increments in proportion to the lengths of the horizontal distances. Corrections to increments of coordinates are calculated by the formulas
The control of the correct distribution of residuals is carried out in accordance with the dependencies
The corrections are rounded up to 0.01 m and the obtained values in centimeters are recorded in columns 7 and 8 above the coordinate increments.
11. The corrected values of the increments ∆x′ i and ∆y′ i are calculated by the formulas
and write out in columns 9 and 10 of the calculation sheet.
The control of calculations is carried out according to the formulas
12. Calculate the coordinates of the traverse vertices
where X i-1 , Y i-1 and X i , Y i are the coordinates of the previous and subsequent vertices of the theodolite traverse.
The control of the correctness of the calculations is the coincidence of the calculated coordinates of the end point of the theodolite traverse. In our example (see table 4) these are the coordinates of pz 7109.
Similarly, the coordinates of the points of the diagonal theodolite traverse are calculated. Sample processing is shown in table 8
Creation of mine surveying reference networks in a quarry.
Basic mine surveying network (OMS) - a system of points fixed on the earth's surface and in mine workings.
It is created for the preparation of mining and graphic documentation and for solving mine surveying tasks.
CHI basis
1. Points of the state geodetic network (I, II, III, IV classes)
2. Condensation networks
Conditions for the creation of an OMS:
1. Points should be evenly spaced along the sides of the pit
2. There must be visibility for each item
3. Ensuring the safety of items for a long time
4. Taking into account development prospects mining
If the territory is built up, then at least 4 points per 1 km 2 are created, if not built up, then 1 point per 1 km 2.
The points of the reference high-altitude network are determined by leveling III and IV class
OMS can be created using GPS receivers.
Filming network
22.Creation of mine surveying networks in a quarry (polar method, theodolite traverses).
Filming network- a number of points with known coordinates. It is created on the basis of reference.
polar way - They are used in quarries, where mining sites are significantly removed from the points of the geodetic base. Distances are measured with light rangefinders, angles are measured by T5, T15, T30.
Theodolite traverses - in quarries with an elongated front of work and wide working platforms of ledges. The course is closed between reference points. Lengths are measured with tape measures or a rangefinder.
23. Creation of surveying surveying networks in a quarry (Serifs, method of operational grid).
The creation of mine surveying survey networks in a quarry is performed using serifs.
Mine Surveying Networks- a network of points evenly located on the surface and inside the quarry, used for surveying mine workings and solving mining problems
On the ledges, the distance between the points of the survey network, for example, during tacheometric survey, should not exceed 300-400m.
1. Geodetic serifs- used to insert individual points, if visibility is provided from the working ledges to the control points
- straight serif- to ensure the accuracy of the angle at the determined point between the two beams, it should be from 30 to 120 degrees, at least 2 notches.
- resection– allows you to reduce field work to a minimum. The accuracy depends on the errors in the starting points.
- lateral notch
Creating a production grid.
It is used in the development of deposits by dredging hydraulic method and if the quarry is on a flat surface and not deep. A production grid is created that represents a network of squares - the vertices of the squares are survey points. We select strong points, lay a polygonometric course.
24. Capturing details on quarries
Survey objects: elements of mine workings, industrial facilities, roads, power lines, exploration workings (wellheads, sampling points), overburden dumps, warehouses.
Ledges are removed monthly, other objects as needed.
Methods used when surveying a quarry:
1. Tacheometric- for small quarries. Shooting characteristic points, the distance between the points is 50 m, the device must be located at a distance of no more than 100 m from the points, all results are recorded in a log.
2. stereophotogrammetric- (scanner) - in large quarries, the advantages of this method are that field work is carried out quickly, the disadvantage is expensive equipment.
3. Perpendicular method- next to the contour there should be a side of the theodolite traverse, lay perpendiculars to the characteristic points.
Topographic survey is a complex of geodetic works performed on the ground for the preparation of topographic maps and plans. There are surveys for compiling topographic plans of large scales (1:500, 1:1000, 1:2000, 1:5000) and small scales (1:10000, 1:25000 and smaller). In engineering geodesy, surveys are mainly carried out on a large scale.
All elements of the local situation, existing buildings, landscaping, underground and surface utilities, as well as the terrain are subject to survey and display on topographic plans.
The points that determine the position of the contours of the situation on the plan are conditionally divided into solid and non-solid. Solid include clearly defined contours of structures built from durable materials (brick, concrete), for example, the corners of capital buildings. Contours that do not have clear boundaries, such as meadows, forests, arable land, are classified as non-solid.
Topographic plans are marked with points of planned and high-altitude geodetic networks, as well as all points from which surveys are made, if they are fixed by permanent signs. On specialized plans, it is allowed to display not the entire situation of the terrain, but only those objects that are necessary: the use of non-standard heights of relief sections, a decrease or increase in the accuracy of depicting contours and surveying relief.
Topographic surveys are carried out in three main stages:
Preparatory stage. Receipt of technical specifications from the Customer and preparation of contractual documentation. Collection and analysis of materials from previously performed geodetic works (survey networks, topographic surveys, etc.) on a given territory. Implementation of registration (obtaining a permit) for the production of topographic and geodetic works.
Field stage. Reconnaissance surveys of the territory and the creation of reference geodetic networks using GPS, the creation of planned high-altitude survey geodetic networks. Topographic survey, including survey of underground and elevated structures.
camera stage. Drawing up (updating) a topographic plan - final processing of field materials and data with an assessment of the accuracy of the results obtained. Coordination (if any) of communications plotted on topographic plans (power lines, communication lines, main pipelines, etc.) with organizations in charge of these objects. Preparation of a technical report.
Topographic survey is performed from points of the terrain, the position of which in the accepted coordinate system is known. Such points are points of reference state and engineering-geodesic networks. However, their number, falling on the area of the surveyed area, is mostly not enough, so the geodetic base is thickened by the rationale, called surveying.
The survey substantiation develops from the points of planned and high-altitude reference networks. In survey areas up to 1 km 2, a survey substantiation can be created in the form of an independent geodetic reference network.
When constructing a survey justification, the position of points in the plan and in height is simultaneously determined. The planned position of the survey justification points is determined by: theodolite and tacheometric traverses, the construction of analytical networks from triangles and various kinds of serifs. The heights of survey justification points are most often determined by geometric and trigonometric leveling.
The most common type of survey planning substantiation is theodolite traverses based on one or two starting points, or traverse systems based on at least two starting points. Nodal points are formed in the system of moves at their intersections, where several moves can converge.
The lengths of theodolite traverses depend on the scale of the survey and the conditions of the surveyed area. For example, for surveying a built-up area at a scale of 1:5000, the travel length should not exceed 4.0 km; on a scale of 1:500-0.8 km; in the undeveloped area, respectively, 6.0 and 1.2 km. The length of the lines in the survey theodolite passages should be no more than 350m and no less than 20m. Relative linear residuals in passages should not exceed 1:2000, and under unfavorable measurement conditions (thickets, swamps) - 1:1000.
The angles of rotation at the points of passages are measured by theodolites with a root-mean-square error of 0.5 "in one step. The discrepancy between the values of the angles in half-steps is allowed no more than 0.8". The length of the lines in the moves is measured with optical or light range finders, measuring tapes and tape measures. Each side is measured twice - forward and backward. The discrepancy in the measured values is allowed within 1:2000 of the measured line length.
Figure 2. Scheme of the theodolite traverse
When determining the heights of the survey justification points by geometric leveling, the discrepancy in the course should not exceed 5√Lcm, by trigonometric leveling - 20√Lcm, where L is the length of the course, km.
Surveying points are usually fixed on the ground with temporary signs: wooden stakes, poles, metal pins, pipes. If these points are supposed to be used in the future for other purposes, they are fixed with permanent signs.
For the preparation of topographic plans, the following are used: analytical, scale, tacheometric, aerial phototopographic phototheodolite methods of surveying, surveying by leveling the surface and using satellite receivers. The choice of which method to use depends on the conditions and scale of the survey.
With the development of a survey geodetic network in a polar way using electronic total stations, the lengths of polar directions can be increased up to 1000 m. The root mean square error in measuring horizontal angles should not exceed 15 "". A single traverse must be based on two reference points and two reference directional angles.
When creating a survey network, it is allowed: laying a theodolite traverse based on two starting points, without an angular reference on one of them. At the same time, to control angular measurements, directional angles to reference points of reference geodetic networks or directional angles of adjacent sides obtained from astronomical or other measurements (with an average square error of not more than 15 ""), coordinate binding (without measuring adjoining angles) to points reference geodetic network, subject to the performance of angular measurements, in two ways.
Types of theodolite passages are shown in the figure ...
Figure 3. Types of theodolite moves
The development of a planned-altitude survey network using electronic total stations with registration and accumulation of measurement results (horizontal distances, directional angles, coordinates and heights of points and points) is allowed to be carried out simultaneously with the production of topographic surveys.
When creating (developing) a survey geodetic network, the limiting lengths of theodolite traverses and their limiting absolute discrepancies should be taken in accordance with Table 3.
Table 3
Tolerances in traverses
|
Maximum length of the theodolite traverse, km |
Limit absolute discrepancy of theodolite traverse, m |
|||
|
Topographic survey scale |
between reference geodetic points |
between origins and anchor points (or between anchor points) |
Built-up area, open area in undeveloped area |
Undeveloped area covered with wood and shrub vegetation |
When using light rangefinders and electronic total stations to measure the sides of the theodolite travel, the maximum travel length can be increased by 1.3 times, while the limit lengths of the travel sides are not set, and the number of sides in the travel should not exceed: when shooting at scales of 1:5000 and 1 :2000 in open areas - 50 and in closed areas - 100; when surveying at a scale of 1:1000 - 40 and 80, respectively, to the characteristics of the terrain, and when surveying at a scale of 1:500 - 20. The maximum lengths of theodolite traverses and their maximum absolute discrepancies for surveying at a scale of 1:200 are set in the survey program.
A planned survey justification can also be created as follows:
1) Direct serifs should be performed from at least three points of the reference geodetic network so that the angles between adjacent directions at the point being determined are not less than 30° and not more than 150°.
2) Resections must be carried out at least at four points of the reference geodetic network, provided that the point being determined is not located near a circle passing through three starting points. 3) Combined serifs should be built by a combination of direct and reciprocal serifs using at least three starting points.
The heights of the survey network points are determined by technical (trigonometric) leveling. Technical leveling courses should be laid, as a rule, between the benchmarks (marks) of leveling II-IV classes in the form of separate courses or systems of courses (polygons). Closed courses of technical leveling are allowed, based on one initial benchmark (passages laid in the forward and reverse directions). When constructing a high-altitude survey network, in the absence of benchmarks and marks of the state leveling network on the site of engineering surveys, technical leveling moves must be fixed with leveling marks at the rate of at least two per work area and at least 3 km apart from each other. Permissible lengths of technical leveling moves, depending on the height of the relief section of the topographic survey, should be taken from Table 4.
Table 4
Permissible stroke lengths for technical leveling
Technical leveling (Figure 8) should be carried out with levels (type 3N-5L, 2N-10KL or equivalent), as well as theodolites with compensators (type T15MKP, etc.) or a level at the pipe, with a reading on the middle thread on both sides of the rail.
Figure 4. Technical leveling
The discrepancy between the elevation values obtained at the station on both sides of the rails should not be more than 5 mm. The distance from the instrument to the places where the rails are to be installed should be as equal as possible and not exceed 150 m. If the number of stations per 1 km of the course is more than 25, the discrepancy of the leveling course or the polygon should not exceed mm, where n is the number of stations in the course.
Trigonometric leveling should be used to determine the heights of survey geodetic network points in topographic surveys with a relief section height of 2 and 5 m, and on hilly and rugged terrain - after 1 m. Points whose heights are determined by the method of geometric leveling should be used as initial points for trigonometric leveling. In mountainous areas, it is allowed to use as starting points the state or reference geodetic network, the heights of which are determined by trigonometric leveling in accordance with the requirements. The length of trigonometric leveling moves should not exceed 2, 6 and 12 km, respectively, in topographic surveys with a relief section height of 1, 2 and 5 m.
Trigonometric leveling of the points of the survey network should be carried out in forward or reverse directions with the measurement of vertical angles by theodolite along the middle thread in one step at two positions of the vertical circle. It is allowed to use hanging strokes of trigonometric leveling in length, with the measurement of vertical angles in one direction along three threads at two positions of the vertical circle. The fluctuation of the "zero point" at the station should not exceed 1. The height of the instrument and sighting targets should be measured with an accuracy of 1 cm.
The discrepancy between the direct and reverse elevations for the same line during trigonometric leveling should not be more than 0.04S, m, where S is the length of the line, expressed in hundreds of meters. Permissible discrepancies in traverses and closed polygons of trigonometric leveling should not exceed the value
where S is the length of the traverse in meters and n is the number of lines in the traverse or polygon.
1.3 Development of survey justification and survey of the situation and relief using global navigation satellite systems
Shooting justification
6.1. General provisions
6.1.1. A survey substantiation is created in order to thicken the planned and high-altitude base to a density that ensures the survey of the situation and relief by one method or another.
The density and location of survey justification points are set in the technical project depending on the chosen method of surveying the situation and relief.
With the stereotopographic survey method, the location of survey justification points is determined by the selected survey technology, photographing height and aerial photography scale.
6.1.2. The survey substantiation is developed from points of state geodetic networks, geodetic networks of condensation of 1 and 2 categories and technical leveling.
The planned coordinates and heights of the survey justification points using global navigation satellite systems are determined by building survey networks or by the method of hanging points.
6.1.3. The marginal errors in the position of planned survey substantiation points, including planned identification marks, relative to the points of the state geodetic network should not exceed 0.2 mm in the open area and in the built-up area on the map or plan scale and 0.3 mm - for large-scale survey on the ground, closed trees and shrubs.
6.1.4. Surveying substantiation points are fixed on the ground with long-term signs in such a way that each shooting tablet, as a rule, has at least three points when surveying at a scale of 1:5000 and two points when surveying at a scale of 1:2000, including points of the state geodetic network and concentration networks (if specifications customer in the technical project does not require a higher density of fastening). The density of fixing points of the survey justification when shooting at a scale of 1:1000 and 1:500 is determined technical project.
Within the territory of settlements and industrial sites, all points of the survey substantiation (including planned and high-altitude identification marks) are fixed with signs of long-term fixing.
Types of signs of long-term and temporary fixing are shown in Appendix 4.
6.2. Survey Design Guidelines
The design of the survey justification should be carried out taking into account the requirements of these Instructions, depending on the scale and method of the forthcoming survey. In this case, special requirements for geodetic networks of design and other organizations should also be taken into account. The basis for the design should be: collection and analysis of information and materials on all previously performed geodetic works at the survey site; study of the area of forthcoming work on the basis of available maps of the largest scale and literary sources; study of the materials of the
special survey of the work area, including survey and instrumental search for geodetic signs of previously completed work; choosing the most appropriate option for the development of geodetic constructions, taking into account the prospects for the development of territories.
The graphical part of the survey justification project is usually made up on maps of a scale of 1:50000 - when designing a survey at a scale of 1:10000, and on maps of a scale of 1:10000 and 1:25000 - when designing large-scale surveys.
6.2.1. During the design process, it is necessary to General requirements on design, set out in Section 4, a number of the following specific requirements related to the use of satellite equipment to create a survey justification:
6.2.1.1. Determine the type and operational characteristics of the satellite equipment to be used for the performance of work, guided by the recommendations given in subsections 5.2 and 5.6.
6.2.1.2. In accordance with the given survey scale and the height of the relief section, select the method of satellite determinations and the method of developing the survey justification, guided by the recommendations given in subsection 5.5 and in subsections 6.2.5-6.2.7.
6.2.1.3. Based on the materials of the topographic and geodetic knowledge of the object of work, select the points of the geodetic basis for the development of survey justification in accordance with the requirements of paragraphs 6.2.2, 6.2.4.
6.2.1.4. Draw up a survey justification project in accordance with the requirements of subsection 6.1 and clause 6.2.3, satisfying the requirements for the unobstructed and noise-resistant passage of radio signals in accordance with the recommendations given in subsection 5.3.
6.2.1.5. Prepare a work program for field work on the development of a survey justification using satellite technology in accordance with the general recommendations given in paragraph 6.2.8 and recommendations on paragraphs 6.2.9, 6.2.10, if the development of the survey justification is designed by the network building method, or according to clause 6.2.11, if the development of the survey justification is planned to be carried out by the method of determining hanging points.
6.2.1.6. Refine the work program of field work based on the results of reconnaissance (see subsection 6.3).
6.2.1.7. Plan to check the readiness of equipment and performers for work at the facility in accordance with the recommendations given in subsection 5.7.
6.2.1.8. Give general guidance on the implementation of satellite determinations in accordance with Section 5.9.
6.2.1.9. Schedule the computational processing of the results of satellite observations in accordance with the recommendations under item 6.2.12.
6.2.2. The geodetic base used for the development of survey substantiation and survey of the situation and relief by means of satellite determinations must meet the requirements for the unhindered and noise-resistant passage of radio signals in accordance with the recommendations given in subsection 5.3.
6.2.3. If it is planned to survey the situation and relief using satellite technology at the object, the creation of geodetic thickening networks, survey justification and its thickening is not required, since the methods of satellite determinations in terms of range and accuracy fundamentally provide the possibility of surveying directly on the basis of the state geodetic
a leveling network having a density according to clause 2.22. At the same time, at the points of this network there should be no factors that reduce the accuracy of satellite determinations, described in paragraphs 5.3.4-5.3.6.
6.2.4. As starting points from which the survey justification is developed (hereinafter referred to as starting points), all points of the geodetic base located within the object and closest to the object outside it, but not less than 4 points with known planned coordinates and at least 5 points with known heights, so as to ensure that the survey substantiation is brought into the system of coordinates and heights of the points of the geodetic base.
6.2.5. To develop a survey justification using satellite technology, depending on the projected survey scale and the height of the relief section, one of two methods should be used - the network construction method or the method of determining hanging points.
6.2.6. When designing a survey justification for shooting a specific object
at the required scale with a given height of the relief section, it is necessary to choose the method of satellite determinations - static, fast static, or the reoccupation method (see subsection 5.5).
6.2.7. Instructions on the choice of the method of development of the survey justification and the method of satellite determinations, depending on the scale of the survey and the height of the relief section, are contained in Table 6.
Table 6
| Scale | Planned justification | Planned high-rise or high-rise |
||
| shooting; | justification |
|||
| height | ||||
| sections | ||||
| relief | ||||
| Development method | Method | Development method | Method |
|
| shooting | satellite | shooting | satellite |
|
| justification with | definitions | justification with | definitions |
|
| using | using | |||
| satellite | satellite | |||
| technology | technology | |||
| 1:10000, | definition | quick | building a network | quick |
| 1:5000; | hanging items | static | static |
|
| 1m | or | or |
||
| reoccupation | reoccupation |
|||
| 1:2000, | building a network | quick | building a network | quick |
| 1:1000, | static | static |
||
| 1:500; | or | or |
||
| 1 m or more | reoccupation | reoccupation |
||
| 1:5000; | definition | quick | building a network | static |
| 0.5 m | hanging items | static | ||
| or | ||||
| reoccupation | ||||
| 1:2000, | building a network | quick | building a network | static |
| 1:1000, | static | |||
| 1:500; | or | |||
| 0.5 m | reoccupation | |||
6.2.7.1. The method of developing a survey justification by determining hanging points is recommended to be used when preparing a survey geodetic base on a relatively small scale with heights of the relief section of 1 m, 2 m or more, that is, in cases where obtaining high-precision materials is not required.
6.2.7.2. The method of developing a survey justification by building a network is recommended for use in order to obtain the most accurate planned coordinates and heights of points necessary for surveying the largest scales with all regulated (see clause 2.11.1) values of the height of the relief section (from 0.5 m to 5 m).
6.2.7.3. The fast static method of satellite determinations in the production of work on the development of survey justification is the main one. It allows determining the planned coordinates of points and their heights with sufficient accuracy and high efficiency for most of the scale range and heights of the relief section.
6.2.7.4. The reoccupation method replaces the fast static method in those cases when, according to the conditions of the work, it is advantageous to carry out two short-term receptions of observations of satellites spaced in time, instead of one long-term reception.
6.2.7.5. The static method of satellite determinations, due to the relatively low efficiency of the work, can be applied in cases where, with a relief section height of 0.5 m, it is technically and economically expedient to carry out not leveling work, but satellite determinations to obtain a high-altitude survey base.
6.2.8. The field work program for the development of a survey justification using satellite technology should at its core be a list of
sessions, each of which includes techniques performed at the points of the work object.
The work program of field work should include the following data:
6.2.8.1. The name of the object of work.
6.2.8.2. Type of developed survey substantiation (planned, high-rise or planned-high-rise).
6.2.8.3. The scale and height of the relief section of the projected survey work.
6.2.8.4. List of equipment and software used.
6.2.8.5. Applied methods of satellite determinations.
6.2.8.6. Receive duration values for planned satellite detection methods and different numbers of observed satellites (see § 5.5.3).
6.2.8.7. Values of the interval of registration of satellite observational data for the methods of satellite determinations planned for use.
6.2.8.8. Instructions on the procedure for conducting field work at the facility using satellite determination methods (described in subsection 5.5), including:
session numbers;
numbers of receivers used at certain points of the geodetic base or survey justification for performing reception, indicating the names of these points and marking the numbers of receivers received in sessions as base stations;
methods of satellite determinations used to perform certain sessions.
An example of the design of a work program for field work is given in Appendix 5. The column "Date and time intervals at which the configuration parameters of the satellite constellation are optimal for satellite determinations" of Table 5.2 of this Appendix is filled in at the stage of preparation for field work (see subsection 6.4).
6.2.9. When designing the development of a survey justification by the method of building a network, the program of field work at the site must be drawn up so that all lines of the network are determined independently of each other, including lines based on geodetic datum points. In this case, it is necessary to design the definition of lines from each newly determined point of the survey justification to at least 3 points. An example of a scheme for the development of a survey justification by the method of building a network is shown in Fig.1.
Altitude geodetic base point
Point of the planned geodetic base
Fig.1. An example of a scheme for the development of a survey justification by the method of building a network
6.2.10. In the case of designing the use of 2 receivers for satellite observations, the implementation of the instructions in clause 6.2.9 does not cause difficulties. However, if more than 2 receivers are planned to be used at the object, and work is designed to be carried out in sessions that include observations at 3 or more points, then when compiling a field work program, it is necessary to designate such lines for each session as independently determined lines, a broken line from whose connection does not intersect itself at the connection points of the lines and does not close.
As an example, Fig. 2 shows a diagram illustrating the project of independent determination of 3 lines from a session performed at 4 points. As can be seen in Fig. 2, the broken line, composed of lines 1-2, 2-3, 3-4, does not intersect itself at the connection points of the lines and does not close. For independent determination of lines 1-3, 1-4, 2-4, one more session must be performed at these points. As can be seen in the figure, in this case, the broken line from the connection of these lines does not intersect itself at the points of connection of the lines and does not close.
independent measurements
dependent measurements
Fig.2. Diagram illustrating the design of independent definition of 3 lines from a session,
performed at 4 points
6.2.11. When planning the development of a survey justification by the method of determining hanging points, it is necessary to design the definition of lines from each point of the survey justification to the nearest point of the geodetic base, as well as between neighboring points of the geodetic base (as shown in Fig. 3a), or, if appropriate, it is necessary to design determination of lines from the survey justification points to several nearest points of the geodetic base (Fig. 3b, c), thus obtaining serifs. In all cases, the geodetic construction must include required amount points of the geodetic base (see clause 6.2.4).
Geodetic base point
- point of filming justification
Fig.3. Diagrams illustrating the development project of the survey justification by the method of determining the hanging points
6.2.12. When designing the computational processing of the results of satellite observations, the use of IBM-compatible computers and the use of specialized software packages included in the sets of satellite equipment planned for use are envisaged. Work with these packages should be designed in accordance with the requirements for their use, set out in the operational documentation attached to them. The type of software must be specified in work program field work (see, for example, Appendix 5).
6.3. Reconnaissance and consolidation of points of the survey justification created
using satellite technology
6.3.1. Reconnaissance and fixing of survey substantiation points on the ground is carried out in accordance with the instructions in section 6 of the instruction. At the same time, taking into account the peculiarities of satellite technology, the following tasks are also solved in the process of reconnaissance:
6.3.1.1. Examine the points of the geodetic base and establish their actual suitability for making observations of satellites. Items unsuitable for work should be rejected. In the case of a limited number of geodetic base points suitable for observing satellites available at the facility, measures are outlined to ensure the possibility of making observations at these points (raising the receiver antenna, moving the antenna installation point with determining the reference elements).
6.3.1.2. The possibility of performing satellite determinations at the points of survey justification is checked. At the same time, zones of possible obstacles, distortions and radio interference should be identified (see subsection 5.3) and the arrangement of points planned earlier in the design process should be corrected. Refine location descriptions of items.
6.3.1.3. If necessary, established as a result of the survey of survey substantiation points, preparatory work is carried out:
choose new survey substantiation points to replace those unsuitable for satellite determinations;
make changes to the description of the location of points.
6.3.2. In the process of reconnaissance, it is necessary to keep a log in which, for each point, the azimuths and heights of the boundaries of obstacles should be recorded if the height of the obstacles above the horizon is more than 15 °. In this case, the height of obstacles above the horizon should be determined taking into account the probable height of the receiver antenna.
6.3.3. The points of the survey justification should be fixed on the ground with signs that ensure the long-term preservation of the points and temporary signs, with the expectation that the points will be preserved during the survey (see Appendix 4).
6.3.4. When fixing the points of the survey substantiation with signs of a long-term type, one should be guided by the following.
6.3.4.1. As signs of a long-term type, they use:
a concrete pylon (Fig. 4.1a) with dimensions of 12x12x90 cm, in the upper end of which a forged nail is embedded, and in the lower part, for better bonding with the ground, two metal pins are cemented;
a concrete monolith (Fig. 4.1b) in the form of a truncated tetrahedral pyramid with a lower base 15x15 cm, an upper base 10x10 cm and a height of 90 cm, with a forged nail embedded in it;
a steel pipe (Fig. 4.1c) with a diameter of 35-60 mm, a section of a rail or an angle steel profile 50x50x5 mm (or 35x35x4 mm) 100 cm long with a reinforced concrete anchor at the bottom and a metal plate for inscription at the top; the anchor is made as a steel reinforcement fastened to a pipe (rail, angle), embedded in concrete, in the form of a truncated tetrahedral pyramid, having a lower base of 20x20 cm, an upper base of 15x15 cm and a height of 20 cm;
a wooden pole (Fig. 4.1d) with a diameter of at least 15 cm with a cross, mounted on a concrete monolith in the form of a truncated tetrahedral pyramid with a lower base of 20x20 cm, an upper base of 15x15 cm and a height of 20 cm; on the upper face of the monolith there is a cross-shaped notch or a nail is embedded. The upper part of the post is hewn into a cone, below the hew there is a cutout for an inscription;
a stump of a freshly cut coniferous tree (Fig. 4.1d) (used in forested areas) with a diameter in the upper part of at least 20 cm, processed in the form of a pillar, with a cutout for an inscription and a shelf with a forged nail hammered into it;
brand, pin, bolt fixed with cement mortar in concrete structures of various structures, hard-surfaced land or rocks.
Concrete pylons and monoliths of signs (Fig. 4.1a-d) are laid to a depth of 80 cm.
6.3.4.2. Long-term signs should be dug in as a ditch in the form of a square with a side of 1.5 m, a depth of 0.3 m, a width of 0.2 m at the bottom and 0.5 m at the top. An embankment of soil 0.10 m high should be made around the sign. In areas of swamps, forested areas and permafrost, the embankment is replaced with a log house (1.0x1.0x0.3 m) filled with soil. In this case, the sign is not surrounded.
6.3.4.3. In all cases, long-term signs are installed in places that ensure their safety, safety and ease of use during topographic surveys, surveys and construction, as well as during the subsequent operation of the constructed facility. It is not allowed to lay long-term signs on arable lands and swamps, on the carriageway, near eroded edges of riverbeds and banks of reservoirs, and in other places where the safety of the sign may be violated and where the sign itself may interfere with economic activity.
6.3.5. When fixing the points of the survey substantiation with temporary signs, it is necessary to adhere to the following recommendations.
6.3.5.1. Temporary signs can be tree stumps (Fig. 4.2a), wooden stakes with a diameter of 5-8 cm (Fig. 4.2b), wooden poles (Fig. 4.2c) or metal pipes (angle steel), hammered into the ground by 0.4 -0.6 m, with gatehouses installed nearby (Fig. 4.2d), or a painted cross on a boulder (Fig. 4.2e). Temporary signs are dug in with a ditch around a circle with a diameter of 0.8 m.
6.3.5.2. The center of the temporary sign is indicated by a nail driven into the upper cut of the stake (pillar) or a notch on the metal. In a wooded area, to make it easier to find the sign, if necessary, make marks on the trees with paint.
6.3.6. Each sign of the survey justification is assigned a serial number with
so that there are no signs with the same numbers on the object.
When including in the composition of the survey substantiation of signs belonging to previously created geodetic constructions, the numbers of these signs are not allowed to be changed.
6.3.7. On long-term signs with oil paint, and on temporary signs - with a picket pencil - they write: the abbreviated name of the organization conducting the work, the number of the fixed point (point) and the year the sign was installed.
When using satellite equipment and the software packages attached to it for the development of a survey justification, the stage of preparation for the production of work consists of the following:
fulfillment of the requirements of operational documentation for the preparation of equipment for operation;
checking the readiness of equipment and performers to carry out work according to the working program of field work provided for by the project;
conducting satellite constellation forecasting operations.
6.4.1. Fulfillment of the requirements of operational documentation for the preparation of equipment for operation during the development of a survey justification should be carried out in accordance with the instructions for the operation of the equipment (or replacing them with documents included in the equipment kit).
6.4.2. When checking the readiness of equipment and performers to carry out work on the development of a survey justification, it is necessary to adhere to the recommendations given in subsection 5.7.
6.4.3. Satellite constellation prediction for the development of a survey justification should be performed in accordance with the instructions attached to the software packages and the recommendations given in subsection 5.8.
Based on the time periods obtained as a result of forecasting, which are optimal for observing satellites at each point of the survey justification, overlap zones are found and time periods are set that are optimal for performing the session as a whole. These data in the form of the date of work and the time of the beginning and end of the interval (period) in which the configuration parameters of the satellite constellation are optimal for satellite determinations are entered into the work program of field work (for an example of recording, see Appendix 5, Table 5.2).
6.5 The order of production of field work and general recommendations on computational processing of the results of satellite observations
6.5.1. Field work to develop a survey justification using satellite technology should be preceded by the preparations described in subsection 6.4.
6.5.2. Field work should be carried out in accordance with the technical design, developed taking into account the instructions given in subsection 6.2, according to the work program of field work (see subsection 6.2.8), corrected based on the results of reconnaissance (see subsection 6.3). At the same time, both the method of developing a survey justification (see clause 6.2.5), provided for by the project, and the methods of satellite determinations must be implemented: - fast static, reoccupation method or static, - specified in the working program of field work for certain sessions .
6.5.3. Enlarged field work at the facility consists of the delivery of receivers and equipment to points and the performance of sessions in accordance with the field work program. At the same time, when implementing the fast static and static methods of satellite determinations, it is necessary to perform one reception at each point, and when implementing the reoccupation method, two receptions with an interval of 1 to 4 hours.
6.5.4. In the session, to perform reception at each point, it is necessary to perform the following operations *, adhering to the recommendations given in Section 5.9, and guided by the operational documentation of the type of receiver used:
_________________
The procedure should be specified in the operational documentation of the type of receiver used.
6.5.4.1. Carry out the deployment of the equipment, install the receiver at the point and determine the height of the antenna.
6.5.4.2. Prepare the receiver for operation, as indicated in the operational documentation.
6.5.4.3. Set the acquisition mode of satellite observation data.
6.5.4.4. Using the keyboard, enter into the memory device: the value of the point number, the value of the antenna height and auxiliary information: the start and end times of reception, communication losses, etc.
6.5.4.5. Carry out the reception of satellite observations during the time specified in the work program of field work for the applied method of satellite determinations.
6.5.4.6. Turn off the data logging mode and perform hardware shutdown.
6.5.5. At the end of the work on the object, it is necessary to perform computational processing of satellite observation data.
6.5.5.1. Computational processing is carried out in the following steps:
1) pre-processing - resolution of ambiguities of phase pseudo-ranges to the observed satellites, obtaining the coordinates of the determined points
coordinate system of the global navigation satellite system and accuracy assessment;
transformation of coordinates into the accepted coordinate system (see item 2.20);
adjustment of geodetic constructions and estimation of accuracy.
6.5.5.2. As software for the production of computational processing, software packages attached to satellite equipment used for field work should be used. Examples of such most common software packages are: BL-L1 (Surveyor L1), SKI (WILD GPS System200, Leica SR-9400, Leica SR-9500), GPSurvey (Trimble 4000SSE, Trimble 4000SSi), PRISM (Ashtech Z-12, Ashtech Z-Surveyor).
6.5.5.3. For the production of calculations, it is necessary to use IBM-compatible computers, specifications which meet the requirements set out in the operational documentation attached to the software package.
6.5.5.4. When performing computational work, the operational documentation attached to each software package should be used as a guide.
6.5.5.5. As a result of the computational processing, a catalog of coordinates and heights of survey justification points should be compiled.
6.6. Preparation of reporting materials based on the results of creating a survey justification using satellite technology
6.6.1. Preparation of reporting materials for the creation of a survey justification using satellite technology is carried out in order to draw up a technical report on the work carried out at the facility.
6.6.2. Reporting materials must be prepared in full accordance with the requirements of the current "Instructions for compiling technical reports on geodetic, astronomical, gravimetric and topographic work" () and "Instructions on the procedure for exercising state geodetic supervision in Russian Federation" ().
6.6.3. Reporting materials must fully characterize the methods, the quality of the work performed and all the features of the technology for their execution.
6.6.4. Reporting materials are brochured as constituent part a comprehensive technical report on the object and draw up in accordance with the instructions.
6.6.5. Reporting materials on the creation of a survey justification using satellite technology should contain:
general information (name of organization and year of work; list of instructions and other regulations that guided the performance of work; physical and geographical conditions and administrative affiliation of the area of work; content and purpose of work; scale and cross-section of the relief of the planned survey);
information about topographic and geodetic works of previous years (list and year of work, name of the organization that carried out the work, accuracy and degree of use of work, safety of geodetic points based on the results of the survey);
characteristics of the geodetic base (accepted system of coordinates and heights; density of points; construction of signs and types of centers; accuracy and methods of measurements; instruments; adjustment methods);
information about the work performed (the density of the survey justification, the procedure for fixing points, the measurement technique and the accuracy of the results).
nctroE AND NEG m rsh e ish s h and y y y
And 11.2. Geodetic survey substantiation
A geodetic survey substantiation is created with the aim of thickening (i.e., to further increase the number of geodetic points per unit area) of the geodetic plan and height base to a density that ensures the performance of a large-scale topographic survey (1:5000-1:500). The survey substantiation develops from points of the main geodetic network and concentration networks in the form of theodolite, tacheometric traverses and microtriangulation. The heights of survey network points are determined by geometric or trigonometric leveling.
A theodolite traverse is a closed or open polygon in which all sides dv d2, d n and angles Pj, P2g ---r RL are measured. The sides of the theodolite traverse are measured with a light range finder, a measuring tape (tape measure) or a dual image range finder. Horizontal angles - with scale theodolites of types 4T30Pidr. (Fig. 11.1)
According to the measured sides and angles, after their respective processing, the coordinates of the stroke points are obtained. i.e., the traverse creates additional points with known X. Y coordinates.
A tacheometric traverse is also a closed or open polygon in which all sides, horizontal and vertical angles are measured. The sides of the total station are measured by any range finder (including a filament one), vertical and horizontal angles - by any technical theodolite or total station. As a result of the laying of the tacheometric traverse, additional points with known coordinates are obtained
and heights Xg , Y / " , H I .
Thus, the theodolite traverse determines the position of points only in the plan, and the tacheometric traverse - in the plan, and in height.
d3 Fig. 11.1. Opened
and closed
It is desirable to make the sides of the moves approximately equal. The average length of the sides of the tacheometric and theodolite traverse is 200 - 250 m, the minimum is not less than 40 m. When measuring lengths with a light range finder, the sides can be increased up to 500 m.
Theodolite and tacheometric traverses serve as the geodetic basis for theodolite and topographic surveys and are also used when measuring real estate objects and solving engineering problems.
The coordinates of the points of theodolite and tacheometric traverses and the heights of the points of tacheometric traverses are calculated in the national system of coordinates and heights. For this purpose, theodolite and tacheometric passages are tied to the points of the state network.
■ 11.3. Choice of topographic survey scale and relief section height _ _ _ _ _ _
The scale of the survey and the height of the relief section determine the content and accuracy of drawing the situation and relief on a topographic plan or map.
With an increase in the scale of topographic survey and a decrease in the height of the relief section, the accuracy of plans and maps and the detail of the situation and terrain depicted on them increase. The accuracy of field measurements during the survey should correspond to the accuracy of the scale at which the plan will be drawn up. Therefore, the more accurate and detailed it is required to obtain data from the plan in the design and other calculations, the more accurately the survey work should be carried out and the larger the scale of the plan should be.
However, increasing the accuracy and detail of the survey leads to the complication of the methods of its production and increases the cost of labor and money per unit of area to be surveyed. Therefore, when topographic surveying, it is necessary to choose such a scale and relief section that would provide the necessary accuracy, detail and completeness of the image of terrain elements at the minimum cost of work. Therefore, the main condition right choice the scale of the survey and the height of the relief section is the correspondence between the accuracy of the plan or map and the required accuracy of designing and transferring the project to nature.
Under Precision topographic plan(maps) understand the permissible average or marginal errors in the position of contours, terrain objects and heights of points in relation to
312 to the planned and high-rise justification.
Average errors in the position on the plan of the points of the situation
relative to the nearest points of the survey justification should not exceed ":
Objects and contours with clear outlines - 0.5 mm; in mountainous and forested areas - 0.7 mm;
In areas with capital and multi-storey buildings, the marginal errors in the mutual position on the plan of points of the nearest contours (capital structures, buildings, etc.) should not exceed 0.4 mm.
Average errors of relief survey relative to the nearest points of geodetic justification should not exceed in height:
1/4 of the accepted height of the relief section h at angles of inclination up to 2°;
1/3h at tilt angles from 2 to 6° for scale plans 1:5000, 1:2000 and up to 10° for scale plans 1:1000 and 1:500;
1/2h with a relief section through 0.5 m on plans of scales 1:5000 and 1:2000.
In forested areas, these tolerances increase by 1.5 times. Number of contour lines on maps and plans in areas with slope angles over 6° for plans of scales 1:5000 and over 10° for plans of scales 1:1000 and 1:500 should correspond to the height difference determined at the bends of the slopes, and average height errors characteristic points of the relief should not exceed 1/3 when
taken height of the relief section.
The factors influencing the choice of the survey scale are divided into industrial, natural, technical and economic ones.
AT currently to meet the needs of the industrial
and civil engineering, the choice of survey scale and plans is regulated by numerous normative documents taking into account the specifics certain types construction. For individual design stages, as a rule, two or three survey and plan scales are established.
To precalculate the scale of the survey, taking into account the design requirements for the placement of buildings and structures in kind, with a graphical method of preparing design data, you can use the formula:
where Dstr - building permit for the placement of objects in kind; £pp - graphic accuracy of the scale of the plan; M is the denominator of the survey scale.
To justify the choice of the scale of the topographic survey in the preparation of the cadastral plan, etc., and to reflect reliable data on the quantitative accounting of land, the criterion
riy admissible error in determining the area of the site; in this case, the calculated denominator of the survey scale is defined as
where S is the average area of the assessed site, ha; ms is the allowable error in determining the area (in percent), depending on such factors as the scoring of agricultural land, the cost of urban land, etc.
Relief section height determines the accuracy of the image of the relief and affects the quality of work, especially projects of vertical planning. The height of the relief section is set depending on the scale of the plan and the nature of the terrain in such a way that the horizontal lines on the plan do not merge with each other, the relief is depicted with sufficient accuracy and is easy to read.
For topographic plans and maps at a scale of 1:5000-1:25 000, the height of the relief section can be calculated using the formula:
where M is the denominator of the numerical scale of the plan.
So, for a scale of 1:10 OOO, the value hcalculated according to this formula will be 2 m, for a scale of 1:5000 - 1 m.
The height of the relief section can also be determined from the relations:
h \u003d 5mh or h \u003d 5t, h n "
where mh is the root mean square error in determining the excesses during the survey; tn - root-mean-square error in determining the marks of points along the horizontals on the plan.
Depending on the nature of the terrain (flat, hilly, rugged, mountainous and foothill), 2-4 values of the height of the relief section are taken for each survey scale: for a scale of 1:5000 -0.5 - 5.0 m; 1:2000 - 0.5 -2.0 m; 1:1000 and 1:500 - 0.5 - 1.0 m
In exceptional cases, when surveying prepared and planned areas with maximum prevailing angles of less than 2°, it is allowed to take a relief section height of 0.25 m. apply two elevation section heights. In areas where the distance between the main contour lines exceeds 2.5 cm on the plan, it is imperative to use semi-horizontals * to depict the characteristic details of the relief.
* Instructions for topographic survey at scales 1:5000, 1:2000, 1:1000 and 314 1:500. Moscow: Nedra, 1985.
And 11.4. Theodolite survey_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Theodolite survey is performed to draw up a horizontal (contour) plan of real estate objects with a complex situation, etc. on a large scale (1:500-1:200).
Horizontal angles during shooting are measured with a theodolite, and line lengths are measured with a measuring tape, laser tape measure or range finder with a relative error of not more than 1/2000.
Theodolite survey is carried out from points and sides of the theodolite traverse in various ways (the method of polar coordinates, the method of alignment of perpendiculars, linear and angular serifs), depending on the nature of the terrain, etc. (Fig. 11.2).
Rice. 11.2. Shooting Situations:
a, b - s o b p e r p e n d i k u l y r o v; c - s o b about polar x coordinates; g - sp about s o b o s o u x for sesec ek; d - with a s s o b l e n y x serifs;
e - the way
When shooting, simultaneously with the measurements, an outline is kept (Fig. 11.3), in which the measurement results and the situation are indicated. This information is necessary when drawing up a topographic plan.
g l a v a i
Rice. 11.3. Outline of the shooting area
The method of polar coordinates. It consists in measuring the theodolite horizontal angle from the side of the theodolite traverse to the direction to the point and the distance from the top of the measured angle to the point being taken with a steel tape or laser tape measure, optical or filament range finder.
Perpendicular way. The position of a contour point is determined by measuring with a steel tape measure the length of the perpendicular dropped from the point to the side of the traverse and the distance from the beginning of the side to the base of the perpendicular.
Short perpendiculars are built by eye or using a tape measure, longer ones are built with a laser tape measure.
Angle serif method. This method is used in cases where it is difficult to measure the distance to the determined point. From two points of the theodolite traverse measure the angles between the side
316 moves and directions to the point to be determined by one semi-
with an accuracy of 30". The serif angle should not be less than 30 ° and more than 150 °.
At the end of field work with the help of a coordinator or ruler F.V. Drobysheva et al. build a coordinate grid in the form of a grid of squares with sides of 10 cm. According to the calculated coordinates, points of the theodolite traverse are plotted. The points of the contours on the plan are built from the points of the sides of the theodolite traverse in accordance with the outline (Fig. 11.3).
This method of topographic survey is used in small open areas of terrain with a calm relief.
Linear serif method used when capturing subjects with clear outlines. From two points of the theodolite traverse, the distances to the determined point are measured with a tape or laser tape measure, and the length of the notches should not exceed the length of the measuring device (20-50 m). The corners of the supporting buildings are determined with the control of three serifs.
The alignment method consists in determining the position of objects relative to the alignment line, which is one of the sides of the theodolite traverse. The alignment method is combined with the methods of perpendicular ditches and linear serifs. It is widely used in intra-quarter surveys.
The lengths of the sides of the theodolite traverse are measured with measuring tapes (roulettes) or rangefinders. When measuring line lengths with a tape, the relative error should not exceed 1/2000. can be extended up to 500 m.
The lengths of theodolite traverses depend on the survey scale (Table 11.1). For example, when surveying at a scale of 1:500, the travel distance should not exceed 0.8 km in built-up areas and 1.2 km in undeveloped areas. Horizontal angles in theodolite passages are measured with theodolites of technical accuracy with full reception. The discrepancy between the values of the angle from the half-points should not be more than 1. The tops of theodolite passages are fixed with wooden stakes, metal pins.
The composition of field and cameral work during the laying of a closed theodolite passage 1-2-3-4-5-1 is shown in fig. 11.1. Point 1 of the move is a polygonometry point. Using a theodolite, measure the horizontal angles P), P2, P3, P4. The lengths of the sides of the stroke dx2, d23, d3 4, d4_j are measured with a measuring tape. Each side is measured twice: forward and backward. Measurement accuracy of angles Г, side lengths - Ad / d = 1/2000.
The measurement data of the theodolite traverse is recorded in the journal (Table 11.2).
Permissible length of theodolite traverse, km |
Table 11.1 |
||||
open area, built up |
closed area |
||||
territory |
|||||
For precision traverses |
|||||
Table 11.2
Horizontal angle and tilt angle log
№ No. Position Counts by Difference Average Counts by Place Value
vertical |
horizon |
samples value vertical |
||||
leg circle |
tal |
corner of the circle |
||||
1 ,0 " |
||||||
The measurement data of horizontal angles at two positions of the theodolite vertical circle (KA and KP) are entered in the corresponding column of the journal. The initial data for calculating the coordinates of the points of the theodolite traverse are:
Coordinates of the point 1 x(, yx (for example, polygonometry point); -horizontal distances of the sides of the course; -horizontal angles;
Directional angle of the original side a12; a2 3 \u003d ax2 + 180 ° - P2.
And 11.5. Tacheometric survey _ _ _ _ _ _ _ _ _ _ _ _ _
"Taheo" means quickly. In tacheometric surveying, a tacheometric traverse or theodolite traverse is laid as a survey justification, followed by leveling of its points. To speed up the work, tacheometric survey can be performed simultaneously with the laying of the tacheometric traverse.
A tacheometric traverse is a broken line on the ground, all the vertices of which are respectively fixed. Travel points on the ground are chosen so that mutual visibility is ensured,
overview around the point for the convenience of subsequent shooting within a radius of 150-200 m.
The length of the tacheometric traverse is determined (based on the survey scale and measurement accuracy) by the formula for the limiting relative discrepancy of the tacheometric traverse.
A tacheometric survey is performed with a tacheometer or theodolite when creating plans for land plots on a large scale in rugged as well as built-up areas. With the use of electronic tacheometers, it became possible to create a digital model of the terrain and real estate objects when solving architectural problems. Planned justification is usually created by laying theodolite passages. The marks of the points of theodolite passages are determined by geometric leveling (altitude justification). Shooting of objects, contours and terrain is carried out using the polar method, point marks are determined by trigonometric leveling.
When surveying at a scale of 1:2000 with a section of the relief, horizontals are allowed through 1 m S< 100 м при съемке границ конту ров и 5 < 250 м - при съемке рельефа. Расстояние между пикета ми на равнинной местности не должно превышать 40 м (2 см на плане).
When shooting a situation, terrain, vertical and horizontal angles are measured at one position of the vertical circle of the tacheometer, and the distances to the lath points (pickets) are measured with a range finder.
Lath points are chosen in places characteristic of the vertical structure of the relief - on the tops of hills, watershed lines, banks of water bodies and at characteristic points of the situation.
The order of operation at the station is as follows:
1) set the tacheometer to the working position above the point of the overpowering stroke. In the process of surveying at each station, an outline is drawn up - a schematic drawing of the situation and the terrain, on which the position and numbers of points are shown. This facilitates the subsequent processing of the tacheometric survey results. The work is completed by checking the immobility of the limbus and the constancy of the MO. Measure the height of the device, note
her on a rail and recorded in a journal;
2) perform orientation of the limb to the nearest point of the theo-dolite course;
3) sequentially install the rail on the characteristic points of the terrain and sight it so that the vertical thread of the grid is aligned with the axis of the rail, and the horizontal one is aligned with the height mark of the device i on the rail. Measure horizontal and vertical angles and determine the distance to the rail using a rangefinder.
Office work during tacheometric surveys consists of calculating the angles of inclination, horizontal distances measured distances, elevations, marking points, compiling and designing a plan of the area.
Drawing up and drawing a tacheometric plan includes: building a grid of coordinates, overlaying points by coordinates, drawing lath points, drawing a relief taking into account the direction of lowering the terrain, drawing contours, drawing and designing a plan according to conventional signs of scales 1:5000, 1:2000, 1 :1000 and 1:500.
Drawing up an outline is given Special attention. It is drawn by hand on an arbitrary scale, approximately equal to the scale of the plan. The station from which the survey is being carried out is applied in the middle of the area not being filmed. The ruler draws the previous and subsequent lines of the course. Be sure to indicate the countdown in a horizontal circle, zero along the line of motion along which the limb is oriented.
Apply characteristic points and skeletal lines of the relief, the direction of the fall of the slopes.
When mapping territories, digital topographic survey is used using GLONASS / GPS satellite systems.
11.6. Modern topography_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Digital topography is a modern stage in the development of topography - a geographical and geometric study of the terrain by bringing surveys (on the ground, from the air, from space) and creating topographic maps based on the obtained materials. The main form of survey results in digital topography is digital information.
Automation of the process of ground topographic surveys is ensured by the introduction into geodetic practice of new methods, systems for collecting and primary processing of topographic and geodetic information, from which electronic tachometry can be distinguished.
The effectiveness of the use of electronic tacheometric survey (ETS) in comparison with traditional methods is achieved primarily by increasing the survey area from one station.
Modern electronic total stations combine an electronic theodolite, a rangefinder, a microcomputer with a package
application programs and information recorder (memory module - 320).
To control the operation of the device, control panels with a keyboard for entering data and control signals are used. The measurement results are displayed on the display screen (digital display) and are automatically entered into the memory card. The transfer of accumulated information to a computer can be performed directly from a memory card or by connecting the tacheometer to a computer
With using an interface cable.
AT In principle, the procedure for the production of an electronic tacheometric survey is similar to the survey performed by optical total stations. The electronic tacheometer is installed in the working position at the filming station; at the picket points, special poles with reflectors are sequentially installed, when pointing at them, the distance, horizontal and vertical angles are automatically determined. The microcomputer of the tacheometer calculates the increments of the coordinates Ax, Ay based on the results of measurements, taking into account the corrections. The measurement results are entered into an information storage device, from which the information is transferred to a computer. According to a special program, the final processing is performed to obtain the data necessary to build a digital terrain model or a topographic plan.
And 11.7. Leveling the surface by squares_ _ _ _ _ _ _
The dimensions of the sides of the squares are taken, depending on the complexity of the relief, to be 10 or 20 m. The grid of squares is divided using a theodolite and a steel tape. The tops of the squares are fixed with pegs. The planned position of the reference points is determined by laying theodolite passages, and the vertical position is determined by technical leveling. The sides and vertices of the squares are used to capture the situation in a perpendicular way. From the mark of the vertices of the squares, as well as the characteristic points of the relief inside the squares, they are determined by leveling from one leveling station, selected in such a way that readings can be taken from it along the rails installed at each of these points. Readings are taken only on the black side of the rail. Marks of points are calculated through the horizon of the Yagn device, rounded up to hundredths of a meter and written out on a pre-prepared scheme that replaces the log.
To build a topographic plan based on the results of leveling by squares, a grid of squares is applied to the plan on a given scale and their heights are signed against the tops. According to the outline data, the contours of the terrain are built, after which horizontal lines are drawn by the interpolation method, taking into account the direction of lowering the terrain (Fig. 11.4). The plan is drawn up in conventional signs.
nl -
pm
Solid |
horizontal |
Leveling |
||
surface according to |
||||
held |
||||
squares |
||||
Student Bovylev |
||||
Course 3 Group 10 |
||||
Rice. 11.4. Sample plan for leveling the surface by squares
■ 11.8. Information about satellite positioning systems GLONASS / GPS
There are currently two satellite coordinate systems in operation: the Russian GLONASS (Global Navigation Satellite System) and the US NAVSTAR GPS (Navigation Distance and Time System, Global Positioning System).
Galileo is a European satellite navigation project. Unlike American and Russian systems, the Galileo system is not controlled by any state or military institutions. The development is carried out by the European Space Agency.
The People's Republic of China is developing an independent satellite positioning system, Beidou (literally, the Northern Dipper, the Chinese name for the constellation Ursa Major), which should be transformed into the COMPASS system in the future. Beidou provides today the determination of geographic coordinates in China and neighboring territories.
It was also decided to create its own similar 322 system in India. IRNSS (Indian Regional Navigation Satellite System)
will use 7 satellites to provide regional coverage of India itself and parts of neighboring states.
Currently, there are about 30 NAVSTAR satellites, about 20 GLONASS and 3 COMPASS satellites in near-Earth space.
Table 11.3
Main characteristics of satellite navigation systems
Main characteristics |
|||
Number of I SZ (reserve) |
24 (6 ) |
24 (6 ) |
|
Number of orbital planes |
|||
The number of I SZ in the orbital |
|||
plane |
|||
close to circular |
|||
Orbit altitude, km |
|||
H inclination of orbits, deg. |
|||
Coordinate system |
|||
The satellite positioning system includes three segments: constellations of space vehicles (satellites), ground control and management, receivers (user equipment).
Spacecraft segment. Each of modern systems GPS and GLONASS consists of 24 satellites (21 active and 3 standby) that revolve around the Earth in almost circular orbits. The orbits of GPS satellites are located in six planes with 4 satellites in each (Fig. 11.5, a); the average height of the orbit is about 20,180 km, the period of revolution of satellites around the Earth is 11 hours 58 minutes. Such a number of satellites and their location provide simultaneous reception of signals from at least four satellites anywhere in the world at any time.
GLONASS satellites revolve around the Earth in three orbital planes of 8 satellites in each (Fig. 11.5.6) at an altitude of about 19,150 km, the period of revolution is 11 hours and 16 minutes.
Each GPS and GLONASS satellite has solar panels power supply, receiving and transmitting equipment, frequency and time standards, on-board computers and reflectors for laser ranging.
Ground control and management segment consists of a network of satellite tracking stations evenly distributed throughout the country, a precise time service, a main station with a computer center and a station for downloading data to the satellites. From the tracking points twice a day, the distances to each of the satellites are measured by a laser range finder. The collected information about the position of satellites in orbits (ephemeris) is
given to the on-board computer of each satellite. Satellites continuously emit measurement radio signals, system time data, their coordinates, etc. for users.
Rice. 11.5. Constellations and artificial satellites: a - N AV STA R CPS; b - G L O N A S S
Receiver segment includes satellite receiver, antenna, control unit, power supply
Determining the coordinates of points on the earth's surface using satellites is based on radio ranging measurements of distances from satellites to a receiver installed at the point being determined. If we measure the ranges of up to three satellites (Fig. 11.6), the coordinates of which are known at a given point in time, then the coordinates of the standing point of the receiver P can be determined using the linear spatial notch method. Due to the non-synchronism of the clocks on the satellite and in the receiver, the distances determined to the satellites will differ from true ones. Such erroneous distances are called "pseudoranges". To eliminate these errors, determining the coordinates of points with sufficient accuracy is possible with simultaneous observation of at least 4 satellites.
Satellite positioning systems operate in the Greenwich spatial rectangular coordinate system with the origin coinciding with the Earth's center of mass. In this case, the GPS system uses the coordinates of the world geodetic system WGS-84 (World Geodetic System, 1984), while GLONASS uses the PZ-90 coordinate system (Parameters of the Earth, 1990). Both coordinate systems were established independently of each other based on the results of highly accurate geodetic and astronomical observations.
Most modern receivers work with GPS satellites, so the coordinates of the measured points are most often obtained in the WGS-84 system. To switch to the state or local coordinate system, use the provided program -
324 mi processing transform function.
m CTPBEHM E K Y RT1GRD > I H EU Shi 1n y r m a s
Rice. 11.6. circuit diagram satellite positioning system
■ 11.9. Digital tonographic survey using GLONASS / GPS systems
Methods for determining the coordinates of points. As noted earlier, determining the distances from a satellite receiver to a satellite is nothing more than radio ranging measurements: the receiver receives electromagnetic oscillations from the satellite, compares them with its own generated by its own generator, and as a result determines the range to the spacecraft. Ranges are measured in two ways - code and phase. In the first case, the codes of the signal received from the satellite and those generated in the receiver itself are compared, and in the second, the phases. The most accurate are phase measurements. In GPS, all satellites operate on the same frequencies, but each has its own code. In GLONASS, on the contrary, each satellite has its own frequency, but all have the same codes.
The transfer from the satellite to the receiver of all information is carried out with the help of the so-called carrier electromagnetic oscillations emitted at two frequencies L1 and L2.
The radio signal travels from the satellite to the receiver at a distance of about 20,000 km and is perturbed in the ionosphere, lower atmosphere and near the Earth's surface. The ionosphere, located at an altitude of 50-100 km above the earth, contains free
nye electrons and ions that change the path and speed of radio waves from the satellite. Errors caused mainly by electrons depend on their concentration and, hence, on the satellite elevation angle, geographic location of measured points, time of day and year, solar activity, and can reach tens of meters. These distortions can be eliminated from the observational results by measurements at two frequencies.
In addition to the radio signal from the satellite, the receiving antenna also receives signals reflected from the ground and various objects - buildings, trees, etc. The resulting multipath leads to distortion of the measurement results when using the phase method up to several centimeters, in code measurements - up to meters. In modern receivers, special built-in multipath suppression programs are used to combat this source of error.
One of the factors worsening the results of satellite measurements can also be interference from closely spaced powerful sources of radio emissions: radars, television and radio transmitting stations, etc.
Positioning methods can be divided into two groups - absolute determination of coordinates by the code method and relative phase measurements (see Fig. 11.7).
Rice. 11.7. Satellite positioning methods
When performing absolute measurements, the full coordinates of points on the earth's surface are determined. Observations made at one station, irrespective of measurements at other stations, are called autonomous. Autonomous observations are very sensitive to all sources of error and provide
the accuracy of determining the coordinates is 15 -30 m and are used to find approximate coordinates in precise measurements.
To improve accuracy, absolute measurements can be performed simultaneously at two points: a base station Pv located at a point with known coordinates (usually a point of the state geodetic network), and a mobile station P2 installed above the point to be determined (Fig. 11.8). At the base station, the measured distances to the satellites are compared with those calculated from the coordinates and their differences are determined. These differences are called differential corrections, and the method of measurement is
differential. Differential corrections are taken into account in the course of calculating the coordinates of the mobile station after measurements, or when using radio modems already in the process of measurements. The differential method is based on the assumption that at relatively small distances between stations PJf and P2 (usually no more than 10 km), the measurement errors at them are practically the same. As the distance between stations increases, the accuracy decreases. To improve the measurement accuracy, the observation time is increased, which can vary from several minutes to several hours. The differential positioning accuracy is 1-5 m.
Rice. 11.8. The essence of the differential positioning method
To solve geodetic problems, when it is necessary to obtain the coordinates of points with high accuracy, relative measurements are used, in which the distances to satellites are determined by the phase method, and increments of coordinates or
vector between stations where satellite receivers are installed.
There are two main methods of relative measurements: static and kinematic.
With static positioning, As with differential measurements, the receivers operate simultaneously at two stations - the base one with known coordinates and the one being determined.
After the measurements are completed, the information collected by the two receivers is jointly processed. The accuracy of the method depends on the duration of the measurements, which is chosen in accordance with the distance between the points. Modern receivers make it possible to achieve an accuracy of determining the planned coordinates (5-10 mm) + 1-2 mm / km, altitude - 2-3 times lower.
Kinematic measurements allow you to get the coordinates of points on the earth's surface for short periods of time. In this case, first, the coordinates of the first point are determined in a static way, i.e., they bind the mobile station to the base station, called initialization, and then, without interrupting the measurements, the mobile receiver is set alternately to the second, third, etc. points. For control, measurements are completed at the first point or at a point with known coordinates, where static observations are performed. The accuracy of the kinematic method is 2-3 cm in plan and 6-8 cm in height.
If there is a digital radio channel and data from the base receiver can be transmitted to the mobile station during the measurement process, the coordinates are obtained in real time, i.e. directly at the point being determined.
The main methods of surveying with the use of satellite geodetic instruments are given in Table 1. 11.4.
Table 11.4 |
||||
Parameters characterizing the position determination accuracy |
||||
Measurement mode |
Equipment |
|||
dual frequency |
single frequency |
|||
fast static |
||||
reoccupation |
||||
kinematics and kinematics |
||||
in real time |
||||
Stop - go |
||||
Receiving satellite equipment
Satellite equipment for geodesy is currently 328 produced by more than 50 manufacturers various countries peace, fundamentals
resistant to shock. The high accuracy of coordinate determination makes it possible to successfully use satellite methods for solving a wide range of geodetic problems.
Production of topographic surveys using satellite positioning systems
Topographic survey using geodetic satellite receivers is carried out in three stages: preparatory work, creation of a geodetic survey substantiation, and survey itself.
During preparatory work choose places for fixing the points of survey justification in such a way that there is no interference from nearby structures, crowns of tall trees, sources of powerful radio emission. In addition, special attention is paid to the planning of observations, for which a special module is used in software satellite receiver. This module makes it possible to obtain a characteristic of the positioning process at any point in time and, thus, to select the most favorable period for performing measurements.
Determining the coordinates of points geodetic survey substantiation produced by the method of static satellite observations. The static method is the most reliable and accurate method, which makes it possible to obtain the difference in the coordinates of adjacent points with millimeter accuracy. One of the receivers, called the base receiver (Fig. 11.10, a), is installed on a tripod above the starting point with known coordinates (point of the state geodetic network, geodetic network of condensation), and the second, called mobile, is alternately placed on the points of the survey network. In this case, the condition of synchronous measurements by the base and mobile receivers must be ensured. The observation time is chosen depending on the baseline lengths, the number of simultaneously observed satellites, the class of satellite equipment used, and the observation conditions. Taking into account all the above factors, the measurement time for each baseline can be from 15-20 minutes to 2.5-3 hours. Work with each receiver at the station includes: centering the receiver over the point using a plumb line or optical plummet, measuring the antenna height using a sectional rail, turning on the receiver. When measuring in static mode, no action is required during operation. The receiver automatically tests, finds and locks on all available satellites, makes GPS measurements, and stores all information. After the required observation time has elapsed, the mobile receiver
zzo is transferred to the next determined point. After graduation
measurements, the obtained results are processed, which includes the calculation of the lengths of the base lines and the coordinates of the justification points in the WGS-84 coordinate system, etc. The accuracy of determining the planned location of the points by the static method reaches (5-10 mm) - I - 1-2 mm / kmg high-altitude - 2-3 times lower.
a - static satellite observations at the point; b - kinematic satelite mea surements at a p icket point
topographic survey terrain is carried out by means of kinematic satellite measurements, which make it possible to obtain the coordinates and heights of points in short periods of time. To do this, the base receiver on a tripod is installed at the survey substantiation point, and the mobile receiver is installed one by one at the surveyed points, and the receiver, together with the power source, is located in a special backpack, and the receiving antenna and the controller, which controls the survey process, are mounted on the milestone. (Fig. 11.10, b). First, initialization is performed - binding the mobile station to the base station, for which measurements at the first point are carried out a little longer (20 -30 s) than at subsequent points. After placing the milestone with the antenna on the point and setting all the necessary parameters in the controller (the height of the antenna installation on the milestone, the number of the picket, its attribute, for example: fence angle, manhole, etc.), they start shooting, controlling the verticality of the milestone using the bubble round level. The observation time at a point usually does not exceed 5–10 s, after which the measurements are stopped and, without turning off the receiver, they move to the next point. If the point to be surveyed is located in a
close proximity to buildings, tall trees, and other objects blocking visibility to satellites, the measurement time should be increased. In addition, measurements to such points can be repeated by returning to them again. The survey of the site is completed with observations at the first point or at a point with known coordinates. After the shooting is completed, the results are processed in the same way as in the case of static measurements. The accuracy of the kinematic measurement method is 2–3 cm in plan and 6–8 cm in height. The measurement results can be presented both in digital form and in graphical form.
