Research on Low Earth Orbit Satellite Positioning Technology Based on Time Difference Measurement

With its low delay, global rapid coverage and multi-functional application capabilities, low-orbit satellites provide important technical support for communication, navigation, remote sensing and other fields, and become an important force to promote scientific and technological progress. Positioning low-orbit satellites is the key to ensuring accurate communication beam pointing and optimizing resource allocation to improve communication efficiency and continuity. At the same time, it also helps to monitor satellite signals in real time, evaluate system performance, and provide data support for subsequent satellite planning and deployment, thereby improving communication quality and service level. Among the existing satellite positioning methods, the ephemeris-based method affects the real-time positioning due to the lag of ephemeris update. Although the GNSS method is suitable for active positioning, it has strong dependence. Radar positioning is expensive and easy to interfere with other communication equipment. In view of the limitations of the existing positioning methods, this paper discusses the passive positioning technology of low-orbit satellites based on time difference measurement. The advantage is that it reduces the dependence on satellite data, does not interfere with other communication facilities, and has the characteristics of low cost and high precision. The research method in this paper is realized by a low-cost and efficient single-station positioning system with four antennas. The simulation equivalent test results prove that the method is practical.