GPS软件接收机原理样机设计与实现

Design and realization of a prototype of software GPS receiver

为了满足GPS/INS(Global Positioning System/Inertial Navigation System)超紧组合导航系统研究的需要,克服硬件接收机参数固定,适应性差的弱点,设计了一种参数可调、灵活控制的GPS软件接收机.采用GPS L1频率的中频采样信号,运用FFT(Fast Fourier Trans-form)频域捕获算法和锁相环与锁频环相互辅助的载波环路,实现了信号捕获、码环和载波环路跟踪、导航电文提取与解码、伪距及导航定位解算,并与NovAtel公司的FlexPax型硬件接收机进行了比较.跑车测试结果表明,该GPS软件接收机捕获迅速、跟踪准确,导航定位精度小于10 m,动态抗干扰能力明显优于一般GPS硬件接收机,适合于GPS/INS超紧组合导航系统的应用.

A prototype of software global positioning system （GPS） receiver based on software defined radio techniques to design a flexible and reconfigurable receiver with a wide range of applications was discussed. Compared with hardware GPS receiver, there is a need for a unified platform that allows software receiver de- velopment and research for Ultra-Tightly coupled GPS/INS navigation system, speeds the design process and reduces the costs. A complete software GPS receiver was implemented using fast fourier transform（FFT） ac- quisition approach, delay locked loop, phase locked loop, and the receiver is able to perform acquisition, code and carrier tracking, navigation data decoding, pseudorange calculations, and position calculations. Compared with Novtel＇s FlexPad hardware receiver, the results shows that software GPS receiver is effective in acquisition , steady in tacking and it＇s positioning error is less than 10 m, so it can be applied to an ultra-tightly coupled GPS/INS system.