GPS信号串行捕获算法研究

传统串行搜索算法在时域内对所有可能的频点和相位进行串行搜索,搜索的过程只需要加法和乘法运算,无论是在硬件还是软件中都容易实现,在GPS接收机设计中得到大量应用.但由于串行搜索算法在实际接收机中实现时,捕获过程需要大量的相乘、累加运算,需要较长的捕获时间.文中从降低相乘和累加运算个数入手,提出一种改进算法,使得捕获速度得到明显提高.利用MATLAB分别对传统的和改进的算法进行了算法仿真;根据信号捕获理论结合仿真实验结果,对两种算法进行了比较和分析,认为改进算法可以有效的应用于GPS信号捕获,而且提高了捕获的速度.该算法时于其它系统的伪随机码捕获也是适用的.

Study on the Serial Search Algorithm for GPS Signal

The serial search algorithm searches for a satellite sequentially at each possible code delay and Doppler shift in time domain. Because only addition and multiplication operations are needed, it is easy to implement in time domain. This approach has been exten-sive applications in GPS receivers. Because the serial search algorithm has to do much glide correlation in a teal GPS receiver, this exhausting correlation also tends to be the main weakness of the serial search acquisition. To overcome the shortage of the serial search algorithm, the objective of the study is to shorten the correlation time, and a new algorithm is given. It can decrease the a-mount acquisition time efficient. If this algorithm is implemented in civil GPS receivers, the serial search algorithm will become more feasible and popular. The revisited algorithm aims at not only the GPS signal, but also is suitable for other CDMA systems.