Weak Signal Processing Technology Based on Long-Term Correlation and Autonomous Navigation Application of BDS

Abstract

The service area of BDS navigation system is designed generally in the near-Earth space, which is below the orbit of 1500 km. However, with the development of deep space exploration and other tasks, the positioning requirements of GEO and above orbit satellites or space crafts are increasingly strong. Therefore, it is necessary to analyze and evaluate the position service ability of BDS in high orbit. In this paper, the broadcast signal strength of BDS-3 navigation system satellites is evaluated by using satellite resources already in orbit. In view of the continuous positioning demand of GEO satellite, the simulation verification is carried out, and the sensitivity demand of high-orbit receiver is decomposed. In order to solve the problem of high-sensitivity navigation and positioning reception, long-term correlation (integration time greater than 1 s) technology is used, and orbit-based information assistance technology is used. The sensitivity can reach over −152 dBm under limited embedded computing resources. Compared with traditional processing methods, the sensitivity is improved by more than 9 dB. The GEO orbit operation environment simulation is built through the signal simulator. The high-sensitivity acquisition and tracking technology can improve the coverage rate of BDS positioning in GEO orbit by 30%. Through the orbit dynamics orbit determination method, the positioning accuracy is better than 50 m, which meets the needs of satellite measurement and control.