导航卫星测距码的优选方法

Method of Selecting Ranging-Codes for Navigation Satellites

传统的选择民用测距码可选择组合码的范围较小,难于获得足够多的卫星地址码数和良好互相关性能。文中提出的n级线性移位寄存器的m序列及其优选对的全域搜索算法和导航卫星测距码的生成方案,能够获得所有可能的码序列组合,优选的Gold码族能够产生足够数量的、具有良好互相关性能的测距码序列。通过对比分析优选测距码与GPS C/A码的可分配码数量、自相关及互相关函数特性,初步说明优选测距码的优越性及其优选算法的可行性。

The classical method of selecting ranging-codes is based on the finite field theory so that the range of selecting combination codes is much small, and it is also very difficult to obtain the enough code number and better cross-correlation performance. Therefore, an algorithm of searching the rn sequences and their preferred pairs in the global field is presented in this paper. Meanwhile, three schemes to generate the ranging codes of navigation satellites are also discussed in detail. All ranging-code sequence combinations can be gotten by using the algorithm. And then the ranging-code sequences with enough number and better cross-correlation performance can be generated from the selected Gold code family. Finally, by comparing the selected ranging-codes with GPS C/A codes on the assignable code number and auto-and cross-correlation features, the advantage of the selected ranging-codes and the feasibility of the algorithm can be illustrated preliminarily.