Real-time kinematic real-time dynamic difference method. This is a new and commonly used GPS measurement method. Previous static, fast static, and dynamic measurements all need to be calculated afterwards to achieve centimeter-level accuracy, the GPS-based GPS is a measurement method that can obtain centimeter-level positioning accuracy in real time in the field. It uses the real-time dynamic real-time differential method of the carrier phase, which is a major milestone in GPS application, its appearance brings a new dawn for engineering lofting, topographic map, and various control measurements, greatly improving the efficiency of field operations.
The high-precision GPS measurement must adopt the carrier phase observation. The GPS Positioning Technology is a real-time dynamic positioning technology based on the carrier phase observation. It can provide the 3D positioning results of the measurement site in the specified coordinate system in real time, and the accuracy reaches the centimeter level. In the GPS operation mode, the reference station transmits the observed values and the coordinate information of the Test Station to the mobile station through the data link. The mobile station not only receives data from the reference station through the data link, but also collects GPS observation data, and forms a differential Observation Value in the system for real-time processing. At the same time, the positioning result in centimeter-level is provided, which takes less than one second. The mobile station can be in the static or moving status. You can initialize it on a fixed point before entering a dynamic job, or you can directly start the system under dynamic conditions, then, search and solve the full-week ambiguity in a dynamic environment. After the unknown number is fixed for the whole week, the real-time processing of each calendar element can be carried out. As long as the tracking of more than four satellite phase observations and necessary geometric figures can be maintained, then the mobile station can provide the centimeter-level positioning result at any time.
The key technology of the key technology is the data processing technology and data transmission technology. The GPS Positioning requires the benchmark station receiver to view the observed data in real time (pseudo-distance observations, phase observations) and known data is transmitted to the receiver of the Mobile Station. The data volume is large and generally requires a baud rate of 9600, which is not difficult to implement on the radio. With the continuous development of science and technology, the GPS technology has been developed from the traditional 1 + 1 or 1 + 2 to the wide area differential system WADGPS, and some cities have established CORS systems, this has greatly improved the measurement range of GPS data. Of course, there has also been great progress in data transmission, from the original radio transmission to the current GPRS and GSM network transmission, this greatly improves the data transmission efficiency and scope. In terms of instruments, the current instruments are not only highly accurate, but also more concise and easier to operate than the traditional GPS! How to apply the technology and precautions 1. various Control Measurements traditional geomeasurement and engineering control measurements adopt the methods of triangular network and guide network, which not only consumes time, but also requires cross-site visibility and unevenly distributed precision, in addition, I do not know how accurate it is in the field. I use conventional static GPS measurement, fast static, and pseudo-dynamic methods. In the field test, I cannot know the positioning accuracy in real time, after returning to the internal industry for processing, it is found that the accuracy is not required and must be tested again. Instead, the GPS control and measurement can be used to know the positioning accuracy in real time. If the point accuracy requirements are met, the user can stop the observation and know the observation quality, which can greatly improve the operation efficiency. If you use GPS data for highway control measurement, electronic line control measurement, water conservancy project control measurement, and land measurement, this not only can greatly reduce labor intensity and save costs, but also greatly improve work efficiency, testing a control point can be completed in minutes or even seconds. 2. in the past, when topographic maps were used to measure topographic maps, the root control point of the map should be set up in the test area, and then the total station or theodolite should be placed on the map root control point with the small flat map, now, it has developed to the field industry with the total station and the electronic Hand Book in combination with the ground object code, the use of large-scale ing software for ing, and even to the latest field electronic flat ing, etc, all of these are required to test the surrounding landform and other broken parts on the test site. These broken parts are visible to the test site, and generally require at least 2-3 persons to operate, in the case of a puzzle, once the accuracy is not required, you still need to get the field to go back to the test. Now, when using the GPS Chart, you only need one person carrying the instrument to stay at the ground point to be tested for a second, at the same time, you can input the feature encoding, And you can know the point accuracy in real time through the workbook. After the measurement of an area is completed, you can return to the room, and the required topographic map can be output through professional software interfaces, in this way, only one person is required to use the MNS, and the cross-site communication is not required, which greatly improves the work efficiency. Various topographic maps can be tested using the combination of MnS and workbooks, for example, the general ing, the belt topographic map of railway lines, the highway pipeline topographic map, and the depth detector can be used to test the topographic map of reservoir
Sea and Ocean ing and so on. 3. lofting process lofting is an application branch of measurement. It requires certain methods to use certain instruments to calibrate artificially designed points in the field. In the past, many conventional lofting methods were used, for example, the intersection and Lofting of the theodolite and the corner Lofting of the total station usually need to move the target back and forth when a design point is to be laid out, and it requires 2-3 operations, at the same time, during the lofting process, it is also required that the cross-point visibility should be good, and the efficiency should not be very high in the production application. Sometimes, in the case of difficulties in lofting, many methods can be used for lofting, if you only need to input the coordinates of the designed point to the workbook when you use the technology of GPS, it will remind you to go to the location of the point to be stake out, which is fast and convenient, because GPS is directly flushed out by coordinates, and the accuracy is very high and even, the efficiency in field lofting will be greatly improved, and only one person is needed to operate. Note: This method requires the receiver to maintain continuous tracking of the tested satellite during observation. Once a lock is lost, you need to re-initialize it. With the rapid development of satellite positioning technology, people are increasingly demanding for fast and precise location information. Currently, the most widely used high-precision positioning technology is GPS (real-time dynamic positioning: real-time kinematic). The key to the technology is to use GPS Carrier Phase observation, in addition, the spatial correlation of the observed error between the reference station and the mobile station is used to remove most of the errors in the observed data of the mobile station by means of difference, so as to achieve high precision (in minutes or even centimeters) positioning. The biggest problem encountered in the application of GPS technology is the effective distance of reference station correction data. The spatial correlation of GPS errors gradually loses linearity as the distance between the reference station and the mobile station increases. Therefore, over long distances (single frequency> 10 km, Dual Frequency> 30 km ), after differential processing, the user data still contains a large observation error, which leads to a reduction in positioning accuracy and the inability to calculate the full-week blur of the carrier phase. Therefore, in order to ensure a satisfactory positioning accuracy, the traditional single-host mns' operation distance is very limited. In order to overcome the defects of traditional GPS technology, in the middle of 1990s, people proposed the network GPS technology. In network GPS technology, the linear attenuation Single Point GPS error model is replaced by the linear GPS network error model, the GPS network composed of multiple reference stations is used to estimate the GPS error model of a region and provide correction data for users in the network coverage area. What users receive is not the observation data of a specific reference station, but the data of a Virtual Reference Station, and the correction data of a reference grid that is closer to their own location, therefore, it is also known as the Virtual Reference Site Technology (virtual
Reference), the main direction of the promotion and application of GPS technology 1. Double Star System (GPS + GLONASS Dual System navigation and positioning) is GPS
It can receive about 14-20 satellites, which is incomparable to conventional GPS, this technology enables the gps device to have the ability to reach centimeter-level precision in the shortest time and the strongest anti-interference shielding capability. 2. vrsvrs (Virtual Reference Station) is improving the quality and distance of the positioning, enhancing the reliability of the positioning, and reducing the OTF initialization time. With the VRS technology, the accuracy of the positioning plane position of the GPS data records can be 1-50Km at around 2 cm, without the need to set up your own reference stations. Its application fields will gradually cover land survey, cadastral survey, aerial photography survey, GIS, equipment control, electronic and gas pipeline, deformation monitoring, precision agriculture, water survey, environmental applications and many other fields. VRS is a network-based GPS assignment model proposed by Tianbao. Currently, 90% of Network-related GPS jobs in the world use VRS. 3. The satellite navigation application industry, represented by gpsgps, has become one of the eight most widely recognized wireless industries, it is also one of the three fastest growing information industries in the world (cellular mobile cellular/PCS, Internet/Intranet/Extranet, and Global Positioning System GPS. The integration and integration of GPS and computer, communication, GIS, RS and other technologies will surely extend the application field of GPS technology to a wider extent.
