A Study On GPS/BDS/GLONASS Integrated Positioning

At present, with the rapid development of global satellite navigation systems, GPS becomes mature, GLONASS resume operation, especially with the continuous improvement of China’s Beidou system, the development of the navigation industry has been accelerating. Multi-system navigation positioning has become a hot research field。Therefore, this paper analysis the following contents: multipath error calculating and analysis in observation data quality checking, analysis of SNR,the cycle slip detection of carrier phase observation, analysis of GPS / BDS / GLONASS combination of positioning experiment. The main research of this paper are as follows:1. It introduced the GPS / BDS / GLONASS combination positioning function model and stochastic model, as well as various sources of error correction scheme in precise point positioning data processing.2.For different GNSS systems Multipath Error, it analyzes the variation of different systems multipath error with satellite elevation angle and time, Also calculates the multipath errors on different station each satellite BDS system and analyzes. SNR of different systems for GNSS, it analyzes the variation of different stations in different systems SNR over time3. For the cycle slip detection problem, it uses the ionosphere residual error method and M-W combination method, analyzes the ability of two algorithms of cycle slips.4. It analyzes the combined system location and a single positioning system location,which based on the theory of the GPS / BDS / GLONASS combination of precise point positioning. it selected observations of three IGS stations for testing, the result is that, with better conditions of the satellite, the positioning accuracy of the combined system is better than a single system.But compared to the sophisticated GPS system, positioning accuracy is not obvious. When BDS and GLONASS satellite was poor, the precision of the combined system may become lower than the GPS system. When BDS and GPS certain hours are unable to locate due to poor observation data quality period of time, After the GPS and a BDS combinations, the system can be positioned in this period to ensure that the combination of system targeting reliability.5.In practice measurements, it will cause that the receiver can only receive the satellites which has larger elevation angle, when you may experience the high building or mountain. This paper analyzes the positioning accuracy and PDOP of a single system and its combination systems, when the satellite elevation angle of 15 °, 20 °, 25 °.The results showed that,the higher the satellite elevation angle, the lower the positioning accuracy of a single system. what’s more, the positioning accuracy of combination system is higher than a single system.