面向深组合导航技术的GPS软件接收机捕获算法

Acquisition Algorithms for GPS Software Receiver with Tightly Coupled Integration

通过研究GPS软件接收机的捕获算法,在传统捕获模式基础上面向深组合导航技术,将外部其他导航系统给出的信息反馈入接收机,辅助信号捕获过程,可以使接收机的捕获速度提高数倍。在基于频域相关技术的捕获算法基础上,通过对频域数据进行分析研究,提出了利用伪距信息缩短相关伪码长度,利用多普勒频移信息缩小频率搜索范围以及截短频域信息减少相关运算量等三种提高算法效率,加快捕获速度的改进方案。通过建立捕获算法的仿真模型进行仿真,验证了改进算法的可行性,确定了改进算法的必要参数。仿真结果表明改进算法较普通算法在捕获速度、运算效率上具有显著的优势。

In research of the basic acquisition algorithms for GPS software receiver, an advanced algorithm which uses tightly coupled integration is presented. The new algorithm use information of other navigation systems to help acquiring GPS signals, in which way the speed of acquisition is improved. The new algorithm is based on the theory of frequency correlation. In the new algorithm, the length of the C/A code samples for acquisition is shorten with the help of information of pseudorange; the range of the carrier wave frequency is reduced with the help of information of Doppler shift; the amount of correlation operations is decreased after cutting of useless frequency information. The feasibility of the new algorithm is proved by the emulation with Matlab. The emulation also shows that the new algorithm has obvi- ously advantage on the speed of acquisition as well as the algorithm efficiency compared with the basic algorithm.