| The global navigation satellite system (GNSS) is the use of BeiDou navigation satellite system (BDS) , GPS, GLONASS, GALILEO, and combined with the local area differential and the augmentation system, provide real-time and all-weather navigation service for the world. At present, BDS has been providing PNT services in China and the Asia Pacific Region.GNSS pseudo-range differential positioning as satellite navigation and positioning method of real-time and high positioning precision, it is widely used in the early 80s. At present, China's provinces continuous operation reference station system (CORS) gradually perfect, and accumulated a wealth of reference station data resources, which greatly promoted the advancement and popularization of pseudo-range differential positioning technology.At present, the main way of vehicle navigation and positioning system using a GPS pseudo-range single point positioning mode, due to the impact of single point positioning results by many kinds of errors is significant. In addition, the single system has the disadvantage that the number of observation satellites is small and the constellation structure is poor. In fact, the dynamic positioning can only get the positioning results of the meter level accuracy. Therefore, making full use of observation resources of BDS/GPS/GLONASS multi-mode integrated navigation system, improving the accuracy and reliability of pseudo-range differential positioning, and developing the application software of high precision terminal positioning become the urgent requirements and important development direction for high precision real-time pseudo-range positioning.In this paper, the research of the real-time dynamic positioning technology and the development of the project software system is carried out on the basis of two provincial compatible Beidou CORS in Sichuan and Hebei. Established GNSS sub-meter level positioning service system, applied to the monitoring management about the operation of the vehicle according to the highway lane.Based on the reliable and perfect CORS data, the multi-mode combined pseudo-range differential positioning algorithm is deeply studied, and the software of the BDS/GPS/GLONASS grid pseudo-range differential system is realized. Moreover, the vehicle real-time positioning experiment is carried out,the measured data of CORS are analyzed, the algorithm and software are verified,and some useful conclusions are obtained. The main research contents and achievements are as follows:1. In this paper, BDS/GPS/GLONASS network pseudo-range differential positioning model is derived. On the basis of this, BDS/GPS/GLONASS grid pseudo-range differential positioning model is given.2. Based on the real time static data of Sichuan CORS, the performance of GPS, BDS/GPS and BDS/GPS/GLONASS for grid pseudo-range differential positioning is compared and analyzed. Multi system provides more visible satellites, which can effectively improve the space satellite layout and reduce the dilution of precision, showing higher positioning accuracy, reliability and stability.3. The GNSS grid pseudo range difference system is developed and realized,including service software of GNSS grid pseudo-range differential information generation and terminal application software of GNSS grid pseudo-range differential positioning. Among them, the former is used to generate and broadcast the grid pseudo-range differential corrections, which provides real-time differential correction information for the user (handset). The latter is responsible for the differential positioning of mobile terminal solution to provide real-time location.4. Using Sichuan CORS real-time data, the terminal application software vehicle positioning test is carried out, and the availability of software is verified.whether dynamic or static mode, the real-time positioning accuracy of this system can achieve sub meter level, and has higher reliability and stability.5. Three interpolation methods of inverse distance weighted interpolation,linear interpolation and low surface model method are compared and analyzed.The results show that the inverse distance weighted interpolation method or linear interpolation method is used to generate pseudo-range corrections,accuracy of pseudo-range differential positioning is better. |
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