Research On Real-Time Dynamic Detecting Technologies Of Vehicle GNSS Position

The detection of GNSS navigation and positioning terminal is the important measure of verifying product quality and promoting enterprise development. Currently, the mainly detecting method of navigation and positioning terminals is static way, which can not meet the testing requirements of instantaneity, dynamic performance and continuity. At the same time, the existing detection methods in the stage of laboratory data simulation can not meet the requirement of road inspection. This paper researches a method of dymamic detection based on vehicle motion platform and mainly carries out the work of the following aspects:A high precise GNSS dynamic detection vehicle hardware platform is designed. Through vehicle selection and space planning, the platform integrates GNSS signal synchronization and forwarding module, dynamic detection reference module, cell phone signal enhancement module and electromagnetic shielding module. According to most dynamic positioning terminals'characteristics of independent integrated antenna, the paper focus on researching the GNSS signal synchronization and forwarding scheme, and use the method of a single antemma receiving and wired/wirless forwording to make the GNSS signals of reference equipment and testing equipment to be unified space-time. The experimental data analysis shows that the system positioning deviation of both equipments is less than 5mm, which meets the design requirement of detection accuracy.A high precision terminal positioning algorithm of dynamic detection reference is researched. Users are mostly based on solving L1 or L2 basic ambiguity in the traditional RTK positioning, which has low success rate of ambiguity resolution in a short period by the influence of distance between the base station, precision of atmosphere interpolation error, subscriber station observing environmental and other factors, resulting in too long initialization time or even being unable to fix, and it need to re-initialize after the losing lock of the satellite signal differential or interrupting of network differential signal. In order to improve the instantaneity and continuity of detection reference device, the paper takes priority to fix wide-lane ambiguity by using its long-wavelength characteristics to improve the success rate of ambiguity resolution and reliability, shorten the positioning initialization time and achieve a single epoch centimeter-level positioning. The ultrashort baseline data validation of the algorithm in embedded platform shows that the precision of single epoch resolution is 0.002m in horizontal and 0.006m in vertical, which verify the feasibility of the algorithm.The vehicle motion detection business software is developed. It includes data communication module, original data analysis module, single point positioning module, GGA information analysis module and a motion detection result output module. Implement features are:1) landing CORS service center for achieving on-vehicle devices'dynamic positioning information and analyzing their satellite number, location coordinates, positioning state, DOP values and other data; 2) completing the reference equipment original observations Real-time analysis and storage, and then displaying satellites list, sky map, noise ratio and vehicle speed for users to intuitively understand the current status of satellite observation.3) making real-time statistics of each device initialization time, positioning accuracy, fixed rate, data integrity and other indicators, compared with the reference device to generate the final testing report.Finally, the paper has carried out the actual field testing and analysis for the vehicle real-time dynamic testing system of GNSS positioning. Testing process is divided into static testing, dynamic testing and compatibility testing. Results show that vehicle detection system can meet the needs of field operations; the positioning accuracy of the reference equipment can reach 1cm in horizontal and 2cm in vertical; the system is compatible with the mainstream market brand products, and can provide testing sevices for a variety of rover.