A Quick Location Method for High Dynamic GNSS Receiver Based on Time Assistance

Abstract

Traditional A-GPS positioning method when quickly calculate a position, need a condition that the approximate position must not exceed 150km, otherwise the calculation will be very complex. This paper proposes a time-assisted fast positioning method for high dynamic GNSS receiver, effectively solving the problem of large search calculation in traditional method, even if exact position is unknown after the signal is recaptured. According to the known auxiliary time information and implied  elevation information, this paper put forwards a custom coordinate system for building twodimensional search space, which could reduce the number of search-dimensions. It proposes a search method based on receiver clock calculated by analyzing the influence of time auxiliary accuracy. By using GPS ephemeris data provided by the IGS, it builds a simulation environment and analyzes the influence of different preferred satellites based on the custom coordinate system on the calculation, and thus puts forward a principle for choosing the preferred satellites. Simulation examples show that through the rational combination of satellites to create a custom coordinate system, and when time auxiliary accuracy is less than 60us, the calculation can 100% guarantee to restore a complete satellite signal emission time and obtain an accurate position.