多径干扰是影响北斗GEO卫星的主要误差源之一,为了研究北斗GEO卫星多径误差产生机理,提出了针对北斗GEO卫星星体表面的信号反射模型,并通过基于交叉验证的小波算法对KARR和XMIS站点接收的北斗GEO卫星观测数据进行分析。同时针对反射模型设计出基于“Morlet”连续小波变换的数值优化算法,得到反射参数。KARR和XMIS站的仿真数据表明,文中提出的卫星多径反射模型可以很好地对实测环境中测得的卫星多径进行预测。
It is well known that the geostationary orbits (GEO) satellites work at a high circular orbit 35 786 kilometers above the Earth's equator, and are nearly stationary relative to receivers on the Earth. Therefore they are appointed a dualassignment in satellite navigation system broadcasting the navigation messages to users, and being served as a ranging source. Because of the stationarity, it is hard to separate orbit error from clock error when GEO satellites is used for a range source. Moreover, the multipath interference is another trouble for GEO code ranging. The recent studies showed that the GEO satellites exist range biases which are often assigned to multipath effects, and the multipath errors might come from the satellite. Therefore, we propose a multipath reflection model based on spacecraft and derive the simulation multipath series with supports of the real Beidou observable data, such as pseudorange, and elevation angle. Also, the " Morlet" wavelet is employed to compare the measured and modelled multipath results from the time domain and frequency domain, respectively. In addition, a numerical optimization method is designed to find the optimal reflection parameters that indicate the most possible reflection occurrence places. From the results, the proposed reflection model proposed GEO satellites can well describe the observed code multipath series.