Locata信号的捕获机制研究与仿真

Locata定位系统由于具有定位精度高、布局灵活的特点成为当前卫星导航领域的研究热点,该系统采用的CDMA+TDMA信号结构能够有效克服信号功率差异引起的"远近效应"。本文分析了Locata信号的信号结构特性,将信号的捕获划分为独立的码片搜索阶段和载波搜索阶段并通过matlab仿真验证了该捕获机制的有效性。该捕获机制具有较低的时间复杂度,能够应用于DSP+FPGA框架下的Locata信号的实时捕获中。

Loeata system whieh has the characteristic of high positning presie.ion and flexible distribution becomes the hot issue of current satellite navigation fiehhCDMA＋TI）MA signal structure which is adopted by this system ean ow：reome the ＂near-far effect＂ eaused hy signal power differenee.This paper analyses the characteristic of Locata signal structure ,designs a signal acquisition scheme which contains chip seare.h stage and e.arrier search stage not associated and verifies the availability of the scheme by matlab simulation at last.This scheme which has low time complexity can be used in the real time signal acquisition scheme under the DSP＋FPGA framework. [Key words]