高灵敏度GPS软件接收机开发平台

介绍了GPS软件接收机开发平台的软、硬件结构，重点阐述了基于频域的捕获算法和基于时域的跟踪算法，对导航数据的解调、同步、卫星的星历获取、用户位置解算以及信号仿真模块等做了简单描述，并利用实测数据进行了验证。实验结果表明，开发平台的几何定位精度因子PDOP=2.3534，与传统的硬件接收机相当。开发平台还可以产生多颗卫星、不同中频频率、各种多普勒频移和不同C/A码相位的GPS仿真信号，用于对GPS软件接收机的捕获算法和跟踪算法进行研究和验证。目前采用的捕获算法可以捕获信噪比为-37dB的微弱信号，相对于常规的-19dB的信号门限，灵敏度提高了18dB。

Research of high sensitive GPS software receiver developing platform

First, hardware and software architectures of the software GPS receiver developing platform were introduced, especially the frequency domain acquisition algorithm and time domain tracking algorithm were described in details. Furthermore, the demodulation and synchronization of navigation data, capture of the satellite ephemeris, position solution of the user and simulation of the GPS signal were presented. All of these modules had been validated through field test data. Test results show that the PDOP is 2.3534, which is as good as traditional hardware GPS receiver. The platform can also generate simulating signals of the GPS system including different satellite C/A code, different intermediate frequency, and different Doppler frequency shift, which can be used for validating acquisition algorithm and tracking algorithm of a software GPS receiver. All the satellite signals can be acquired when SNR is -37dB in this platform, which means that the sensitivity has been improved remarkably over traditional hardware GPS receiver.