一种GPS接收机频率检测算法

A frequency detection algorithm for GPS receivers

为了进一步保证全球定位系统(GPS)硬件接收机跟踪环路成功地跟踪GPS卫星信号,设计一种用于时钟频率检测的算法:针对GPS硬件接收机中L1波段(中心频率为1.57542×10^(9)Hz)信号基带处理片上系统(SoC)所需要的时钟管理单元,通过将一个时钟信号到另一个时钟信号的边沿关联起来,准确计算出2个时钟的相对速率及其相位关系,使得每一个进入SoC的时钟信号之间都有明确的相位关系和频率比,为整个系统提供精确的同步时钟源;该模块还能通过全球定位系统核心时钟检测出接收到的带有多普勒频移的粗捕获(C/A)码的频率,以及根据这些时钟源提供的中断给中断控制模块发送信号,以便对其时序协调管理。

In order to further guarantee the tracking loop of the global positioning system(GPS)hardware receiver to track GPS satellite signals successfully,the paper designed an algorithm for clock frequency detection:for the clock management unit required by the signal baseband processing on-chip system(SoC)in the L1 band(center frequency of 1.57542×109 Hz)of GPS hardware receiver,the edges of one clock signal to another clock signal were correlated to accurately calculate the relative rate of the two clocks and their phase relationship,so that each clock signal into SoC had a clear phase relationship and frequency ratio to provide an accurate synchronization clock source for the whole system;moreover,by the module,the received frequency of coarse/acquisition(C/A)code with Doppler shift was detected by the GPS core clock,and the signals were sent to the interrupt control module based on the interrupts provided by these clock sources for the coordinated management of their timing.