Research on doppler locating method of LEO satellite backup navigation system

Abstract

Fast response and low orbit satellites have advantages just like wide coverage, all-weather work, low cost of system construction, and so on, very suitable for positioning service as navigation sources for ground users independent of GNSS, so as to realize the GNSS effective backup navigation means in electromagnetic interference environment. Firstly, low orbit satellite navigation system ground coverage were briefly analyzed, pointed out that in the conditions of global coverage at different time in different locations users may have 1–3 different number of visible satellites. In order to solve the problem of continuous positioning solution under the condition of user different low orbit visible satellite number, and to avoid the system complexity increases due to high precision synchronization required by traditional pseudo-range positioning system, according to the characteristics of the fast speed of the low orbit satellite, a variety of positioning methods were proposed under the condition of different visible satellite number and only using the Doppler satellite observation information, positioning solution iteration formulas were given, and simulation analysis results show that this method can meet the three-dimensional positioning error is less than 20 m in most area. The proposed localization solution method can achieve single point positioning, and can realize continuous observation positioning, using Newton iterative least squares method, with low computational complexity, which is very suitable for fast positioning application for fixed or low dynamic users near the ground.