Geology and Mineral Surveying and Mapping, Volume 22, No.3, 2006
GPS survey technology and its application in engineering survey
three
Lai Jiwen
(Hunan Institute of Geological Surveying and Mapping, Hengyang 42 1008, Hunan)
This paper introduces the system composition, working principle and technical characteristics of GPS. The application of GPS measurement technology in engineering survey is given. And GPS measurement technology of highway engineering.
Compared with the traditional highway engineering survey technology, this paper points out the advantages and development prospects of GPS survey technology in highway engineering survey.
Keywords: global positioning system; GPS measurement technology; Engineering survey; App application
China library classification number: p22814; P 258 document identification code: document number b:1007-9394 (2006) 03-0011-03.
GPS survey technology and its application in engineering survey
La Yi ·J·I2
(Hunan Institute of Geological Surveying and Mapping, Hengyang 42 1008, Hunan)
Abstract: This paper introduces the composition, working principle and technical characteristics of GPS system 2.
The application of GPS measurement technology in highway engineering survey is also given. Then the paper makes a comparison.
Difference between GPS survey technology of highway engineering and traditional highway engineering survey technology
Advantages and development prospect of highway engineering survey.
Key words: GPS global positioning system measurement technology; Engineering survey; app; application
Introduction to 0
Global Positioning System (GPS) is the national defense of the United States.
In order to meet the needs of military departments for high-precision navigation and navigation of land, sea and air facilities
The satellite navigation system developed to meet the requirements of positioning is global, all-weather and continuous.
Sex, real-time navigation, positioning and timing functions can provide accurate three-dimensional for all kinds of users.
Coordinate. The system has been designed and developed since the early 1970s. According to the original text
The design idea is to use the pseudo-random noise code (P code) transmitted by the receiving satellite for the US military and
The allies of the North Atlantic Organization provide meter-level navigation and positioning, and the positioning accuracy will be several.
10 meter C/A code pseudorange provides civil navigation and positioning. GPS as a new generation satellite
Navigation and positioning system not only has global, all-weather and continuous accurate three-dimensional guidance.
Navigation and positioning ability, and has good anti-interference and confidentiality. Global positioning
The rapid development of this system has attracted the general attention of military departments and civil departments in various countries.
Care.
1 GPS survey technology
The high automation of GPS positioning technology, its high precision and its
Potential, but also aroused great interest of the vast number of surveyors. . At that time, GPS positioning
There is basically only one operation mode-static relative positioning, two or more.
The GPS receiver is placed at a fixed point to continuously observe the same group of satellites1~ 2 h.
Or a longer time, through the post-processing of observation data, the basis between the points to be fixed is given.
Line vector, in the case of using broadcast ephemeris, static positioning can obtain 5 mm+ 1 ×.
10-6D (dual frequency) or 10mm +2 × 10-6D (single frequency) baseline calculation accuracy.
With the development of technology, fast static positioning has developed to short baseline measurement.
A new way greatly improves the labor productivity of GPS measurement. A pair of GPS measurements
The system (dual-frequency) normally receives 4 ~ 5 satellites in the short side within the range of 10 km.
Min, the baseline accuracy of 5 ~10 mm+1×10-6d can be obtained, which is equal to 1 ~
The results of static positioning for 2 h or even longer are comparable. Every GPS survey factory
Businessmen are optimistic about this trend and have launched their own new GPS measurement products. Yes, there is.
This new product is called GPS total station, and some are called RTK (real-time dynamic)
Measurement), some are called RTK GPS.
In a word, the continuous development of GPS measurement theory and equipment makes GPS measurement technology
Technology is becoming more and more mature, GPS measurement function is more perfect, GPS measurement is more widely used, and
The price of GPS measuring equipment becomes lower, the operation is simpler, and GPS measurement is more convenient.
Increase practicality and automation. Since 1980s, with the development of GPS positioning technology
The emergence and continuous development of surveying and mapping positioning technology have brought revolutionary changes.
It provides a brand-new technical means and method for engineering survey. For long-term angle measurement,
Conventional ground positioning technology with ranging and leveling as the main body is gradually being used once.
High-speed, efficient and high-precision GPS technology determines three-dimensional coordinates;
The positioning method extends from static to dynamic; Location services have moved from navigation and maps.
The field has been extended to the broad field of national economic construction.
The following mainly introduces the composition and working principle of GPS system and its application in surveying collar.
Application characteristics of the field.
1 1
Date of receipt: March 8, 2006
. 1994-2008 China Academic Journals Electronic Publishing House. Copyright ki.net.
Composition of 1 1 1 GPS system
GPS global positioning system consists of two parts: space satellite group and ground monitoring system.
In addition, measurement users should also have satellite receiving equipment.
Space satellite constellation, the space satellite constellation of GPS consists of 24 satellites with a height of about 200,000 kilometers.
The GPS satellite group is evenly distributed on six orbital planes, and the included angle between the planes.
Is 60, the inclination angle between the orbit and the equator of the earth is 55, and the orbital period of the satellite is
1 1 hour 58 minutes can guarantee the horizon at any time and any place.
It can receive signals from 4 ~ 1 1 GPS satellites at the same time.
The user part of GPS consists of GPS receiver, data processing software and corresponding application programs.
Household equipment, such as computers and meteorological instruments, is used to receive GPS satellite transmission.
Signals, using signals for navigation and positioning, etc. In the field of measurement, with the modern
With the development of science and technology, GPS positioning equipment with small volume and light weight is easy to carry.
High-precision technical indicators bring great convenience to engineering survey.
The working principle of 1 12 GPS
GPS system is a satellite navigation and positioning system using distance intersection method. as soon as...
That is, a GPS receiver is set at the position P that needs to be located and connected at the same time at a certain moment.
Navigation information is received from more than three (A, B, C) GPS satellites, and transmitted through one
At this time, the positioning of GPS satellite by GPS receiver can be obtained through a series of data processing and calculation.
Distance to sap, sbp and scp, these satellites can also be obtained by receiving satellite ephemeris at this time.
Spatial position (three-dimensional coordinates). So as to obtain the P point by the method of distance intersection.
Three-dimensional coordinates (xp, yp, zp), and its mathematical formula is:
energy
2 = [ ( xp - xa ) 2 + ( yp - ya ) 2 + ( zp + za ) 2 ]
sbp
2 = [ ( xp - xb ) 2 + ( yp - yb ) 2 + ( zp + zb ) 2 ]
single cell protein
2 = [ ( xp - xc ) 2 + ( yp - yc ) 2 + ( zp + zc ) 2 ]
( 1)
In the formula (1), (xa, ya, za), (xb, yb, zb) and (xc, yc, zc) are satellites respectively.
Spatial rectangular coordinates of ti moments a, b and c There are generally two kinds of GPS measurement.
Coordinate system, one is fixed in space and the other is in phase with the earth.
The three-dimensional coordinate system is commonly used in highway engineering control survey, which is called three-dimensional coordinate system.
Ground solid coordinate system. (For example: WGS-84 World Geodetic Coordinate System and 1980 Xi 'an.
Geodetic coordinate system. ) In practical use, the conversion parameters between coordinate systems are needed.
Transform the coordinate system and find the coordinates of the used coordinate system. such
It is more conducive to expressing the position of ground control points and processing GPS observation results, so in
It has been widely used in measurement.
Technical characteristics of 1 13 GPS survey
Compared with conventional measurement methods, GPS measurement has the following characteristics:
1) Interstation intervisibility is not required. This feature of GPS makes the selection of points more flexible.
Convenient. However, the sky above the station must be open, so that the received GPS satellite signals will not be dry.
Excuse me.
2) High positioning accuracy. The baseline calculation accuracy of a general dual-frequency GPS receiver is 5 mm.
+1 × 10-6D, while the nominal accuracy of infrared instrument is 5mm+5× 10-6d, measured by GPS.
The accuracy is equivalent to that of infrared instrument, but with the increase of distance, the advantages of GPS measurement become more and more prominent.
Get out.
3) The observation time is short. Observation of each station when using GPS to set up control network
The time is generally about 30 ~ 40 min, and the fast static positioning method is adopted.
The room is shorter.
4) Provide three-dimensional coordinates. GPS measurement is used to accurately determine the plane position of the observation station.
At the same time, the geodetic elevation of the observation station can be accurately determined.
5) simple operation. GPS measurement has a high degree of automation. Current GPS connection
The receiver has been miniaturized and operated foolishly, and the observer only needs to center and straighten the antenna.
Flatten, measure the antenna height, turn on the power supply, conduct automatic observation, and use data processing software.
The three-dimensional coordinates of the measuring point are obtained by processing the data. And other observation work such as satellites.
Capture, tracking and observation are completed automatically by the instrument.
6) All-weather operation. GPS observation can be carried out continuously at any place and at any time.
Generally unaffected by weather conditions.
In China, the application of GPS positioning technology has penetrated into all fields and territories.
GPS has been widely used in the establishment and transformation of network, urban control network and engineering control network.
Technology. In oil exploration, highways, communication lines, underground railways, tunnels,
Building deformation, dam monitoring, landslide, earthquake deformation monitoring, island or ocean survey
GPS technology is also widely used. And DGPS differential positioning technology and
The development of RTK real-time differential positioning system and the release of American AS technology, single point positioning
With the continuous improvement of positioning accuracy, GPS technology is widely used in navigation, real-time vehicle monitoring, petroleum products and other fields.
Exploration point positioning, geological exploration profile measurement, point mapping and lofting will include
The application prospect is broad.
Application of 2 GPS global positioning system in engineering survey
GPS global positioning system is used in engineering survey.
In recent two years, the application of GPS has been rapidly promoted, which mainly depends on GPS.
The system can provide high-precision three-dimensional seating for any user in the world around the clock.
Standard, three-dimensional speed and time information and other technical parameters. Engineering survey is mainly used.
Two functions of GPS: static function and dynamic function. The static function is realized by receiving.
For satellite information, determine the three-dimensional coordinates of a point on the ground; The dynamic function is via satellite.
System, known three-dimensional coordinate points, on-the-spot lofting on the ground. Use GPS static
The combination of state positioning technology and dynamic positioning technology can be used efficiently and accurately.
Complete the highway plane control survey. For example, static function is used in highway control survey.
The accuracy of linear survey using this technology can fully meet the requirements of highway survey and design and the public.
Accuracy requirements of road construction. The following is the application of GPS measurement technology in highway survey.
This paper introduces the application of GPS system in practical engineering survey with examples.
With the rapid growth of the national economy, the construction of domestic high-grade highways is at the forefront.
At the end of the development opportunities, which put forward higher requirements for survey and design, with the highway.
With the development of software technology and hardware equipment in design industry, highway design has realized CAD.
Some software itself also needs the support of ground digital surveying and mapping products; build
Integrated data link of survey, design, construction and post-management to reduce data replication and transmission.
Entering the intermediate link is the requirement of "integration of indoor and outdoor work" in highway survey and design, and it is also
Bottleneck affecting the development of high-grade highway design technology. Current highway survey
Although advanced instruments and equipment, such as electronic total station, are used, the traditional measurement methods still have limitations.
Due to the limitation of visibility and working conditions, the work intensity is high and the efficiency is low, which greatly prolongs the construction period.
Design cycle. The progress of measurement technology lies in the introduction of equipment and technical transformation. At present,
The introduction of GPS technology should be the first choice under the technical conditions of. At present, using GPS static or
The fast static method is used to establish the overall control survey along the line and draw the strip land in the survey stage.
Form a map to provide a basis for the measurement of the route plane, vertical and horizontal sections; In the construction stage, it is a bridge and a tunnel.
The establishment of construction control network is only the first step in the application of GPS in highway survey.
The technical potential of section and highway survey lies in the application of RTK (real-time dynamic positioning) technology.
Among them, RTK technology has a very broad application prospect in highway engineering survey.
Scene. The following briefly introduces the application of RTK technology in highway survey.
2 1 1 RTK positioning technology
Real-time dynamic (RTK) positioning technology is a new development of GPS measurement technology.
Breakthrough has a broad application prospect in highway engineering. As we all know, whether static or static.
Bit, or quasi-dynamic positioning and other positioning methods, because of the lag of data processing, is impossible.
It is difficult to calculate the positioning results in real time, and it is impossible to check the observation data.
In order to ensure the quality of observation data, it is often necessary to rework and retest in practical work.
Unqualified observation results caused by gross error. The main method to solve this problem is
Prolonging the observation time to ensure the reliability of measurement data, thus reducing the
The working efficiency of GPS measurement. The real-time dynamic positioning system consists of reference stations and streams.
The establishment of wireless data communication is the guarantee of real-time dynamic measurement, and its principle is as follows
Install 1 receiver based on the control point with high accuracy of the first point.
As a reference station, the satellite is continuously observed and the receiver on the mobile station is receiving the satellite.
Signal at the same time, through the radio transmission equipment to receive the observation data on the reference station, with
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According to the principle of relative positioning, the computer calculates and displays the three-dimensional position of the mobile station in real time.
Standards and measurement accuracy. In this way, users can monitor the data observation quality of the points to be measured in real time.
The quantity is connected with the baseline calculation result, and the observed value is determined according to the precision index of the point to be measured.
Measure time, thus reducing redundant observation and improving work efficiency.
There are two kinds of real-time dynamic (RTK) positioning measurements: fast static positioning and dynamic positioning.
Mode, the combination of two positioning modes can cover the application of expressway in highway engineering.
Survey, construction lofting, supervision and GIS (Geographic Information System) front-end data collection.
2111/fast static positioning mode
The GPS receiver needs static observation at each mobile station. visible
In the process of measurement, the synchronous observation data of reference station and satellite are received at the same time, and the integer is solved in real time.
If the change of the solution results tends to be stable,
And its accuracy has reached the design requirements, real-time observation can be ended. Usually used for
In control measurement, such as control network encryption; If traditional measurement methods (such as total station measurement) are used
Quantity), which is greatly influenced by objective factors, is implemented in areas with harsh natural conditions.
It is more difficult, and RTK rapid static measurement can get twice the result with half the effort.
Single point positioning only takes 5 ~ 10 min, which is less than 5/5 of the time required for static measurement.
First, in highway survey, it can replace the total station to complete the control point encryption such as traverse survey.
Work.
2 1 1 12 dynamic positioning
Before measurement, it is necessary to observe at the control point for a few minutes (some instruments only need
2 ~ 10 s), and then the rover station can press the predetermined sampling room.
Automatic observation is conducted at regular intervals, and the sampling is determined in real time together with the synchronous observation data of the reference station.
The spatial position of the point. Its positioning accuracy can reach centimeter level. Dynamic positioning mode in
The highway survey stage has a broad application prospect, which can complete topographic mapping and piling.
Survey, cross-sectional survey, longitudinal survey, etc. And the whole measurement process does not need to be connected.
Vision has incomparable advantages over conventional measuring instruments, such as total station.
2 1 1 13 RTK technical advantages
RTK technology mainly has the following advantages:
1) Real-time dynamic display of centimeter-level accuracy measurement results verified by reliability.
(including elevation);
2) Completely get rid of the rework caused by gross errors and improve the efficiency of GPS operation.
Rate;
3) The operation efficiency is high, and each lofting point only needs to stay for 2-4 seconds, with high precision and high efficiency.
This speed is unmatched by conventional measurement;
4) Wide application range, covering highway survey (including horizontal, vertical and horizontal) and construction.
Setting out, supervision, completion survey, maintenance survey, GIS front-end data acquisition and many other aspects;
5) RTK can be combined with total station to make full use of it if there is corresponding software assistance.
Advantages of RTK and total station.
3 Conclusion
To sum up, although the application of GPS measurement technology in highway engineering survey makes
The traditional highway engineering survey technology has developed by leaps and bounds, but compared with the two, it is often
Gauge measurement method also has the following defects:
1) specifications such as the length of attachment line, the length of closed line and the length between node lines.
Strict rules. Because the working face of highway survey is long and narrow, the wire is long.
It is difficult to meet the specification requirements, and there are often operations that exceed the standard.
2) The starting point of route survey control acquisition is generally difficult to guarantee.
For the same measurement system, national measurement, military measurement and urban control points are often mixed together, so this situation will exist.
The compatibility problem between systems, if incompatible starting points are used, will inevitably affect the measurement.
Quality.
3) The destruction of national sites has seriously affected the investigation. Due to the basic control of the state
Most of the system points were completed in the fifties and sixties, and some of them were due to economic construction.
Demand has been destroyed, and some points have been artificially destroyed by human ignorance. therefore
It is often difficult to find the joint measuring point of the conductor. In this way, the quality of line control measurement can not be guaranteed.
Promise.
4) The difficulty of ground visibility often affects the implementation of routine investigation. Due to visibility
Limited by conditions, it is impossible to implement it in a large range of dense forests, dense irrigation and green tent areas.
Conventional control measurement.
Comparatively speaking, GPS survey technology has great advantages in highway engineering survey.
And development prospect:
1) GPS operation accuracy is extremely high. Its operation is not limited by environment and distance.
System, very suitable for areas with difficult terrain conditions and local key engineering areas.
2) GPS survey can greatly improve the work quality and achievements. It is not affected by human factors.
Elements, the whole operation process is controlled by microelectronics and computer technology, since
Dynamic recording, automatic data preprocessing, automatic adjustment calculation.
3) GPS RTK technology will completely change the highway survey mode. RTK can be real-time
And obtaining the spatial three-dimensional coordinates of the position. This technology is very suitable for routes, bridges,
Tunnel survey, it can directly carry out real-time lofting, point survey and so on.
4) GPS survey can greatly reduce labor intensity and reduce logging in the field.
Workload, improve work efficiency.
5) GPS high-precision elevation measurement and high-precision plane measurement are both GPS.
Important field of measurement application. Especially at present, the importance of high-grade highways to mountainous areas is increasing gradually.
Under the development of hilly areas, due to the limitation of topographic conditions in these areas, it is often implemented.
When leveling is difficult, GPS elevation measurement is undoubtedly an effective means.
Application of GPS in highway engineering survey.
And the measuring accuracy and the measuring range are greatly improved.
Efficiency measurement, especially real-time dynamic (RTK) positioning technology will be used in highway survey, construction and
It has a broad application prospect in later maintenance and management.
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