中文摘要：

随着卫星导航系统的发展,可见星数大大增多,为了减少接收机运算量,需选择可见卫星的一个子类。本文分析了卫星导航系统中N个4星最优分布与某4星最优分布中的k（k≤3）个卫星（共4N＋k颗卫星）的联合分布GDOP值,并以此为基础提出了一类低复杂度近似最优的基四选星算法。该算法以经典的4星选择算法（最大体积法和四步选择法）为基础,通过多次迭代与部分执行,实现任意多于4星的卫星选择。仿真结果表明该算法与准优算法相比运算复杂度和GDOP值都更低。

英文摘要：

With the development of the Global Navigation Satellite System（ GNSS） ,the number of visible satellites increases greatly. In order to lower the computational complexity of the receiver,a satellite selection algorithm is essential for choosing a subset of the visible satellites. This paper analyses the Global Dilution of Position（ GDOP） of a joint distribution,which contains the N optimal distributions of four satellites and the k（ k≤3） satellites in an optimal distribution of four satellites. According to the comparison of the GDOP between the joint distribution and the optimal distribution of 4N ＋ k satellites,a four-based satellite selection algorithm is proposed,which has low computational cost and is close to the optimal. The proposed algorithm can select any number of satellites more than four through the iteration and portion of the classic satellite selection algorithm of four satellites,such as maximum-volume algorithm and four-step satellite selection method. Simulations indicate that the proposed method requires less computational cost and achieves lower GDOP than the quasi-optimal algorithm.