一种基于相对位置约束的双星定位方法

A positioning method with two satellites by relative position constraint

全球卫星定位系统(GNSS)需要至少4颗卫星才能提供持续、准确的定位结果。在有障碍物遮挡的城市街道、山谷或者存在压制式干扰的战场环境中,往往会出现可见星数量降低至4颗以下的情况。针对只有2颗可见星的定位问题,提出了通过相对位置变化对绝对位置进行解算的定位模型,证明了该模型的可行性,并研究了该模型的数值计算方法和几何搜索方法。仿真实验和实际跑车试验表明,在只有2颗可见星条件下,该方法的定位精度明显优于传统的INS/GNSS紧组合算法,并且对初始位置的精度不具有依赖性。

The global navigation satellites system （GNSS） needs at least four visible satellites to provide accurate and con- tinuous positing result. However, under harsh conditions such as urban canyon, tunnels and other special environments, the number of visible satellites usually becomes less than four, which leads to degradation of positioning precision or infeasibility of the positioning algorithm. This paper presents a novel method to provide reliable position solution with only two visible satellites. The relative position change during a short period is utilized as a constrain condition to estimate the absolute posi- tion of GNSS receiver in this paper. The feasibility of the proposed method is proved. The numerical algorithm and geomet- rical searching algorithm are proposed respectively. The simulation experiment has been carried out and the result demon- strates that the proposed method is effective in improving the positioning performance. The proposed method has better per- formance than the conventional INS/GNSS coupled method and the positioning results do not rely on the initial position＇s pre- cision.