多普勒与伪码相位值结合的A-GPS快速定位算法研究

辅助全球定位系统通过蜂窝网基站提供给A-GPS接收机捕获辅助信息、辅助星历、时间与概略坐标,解决了微弱信号下的定位问题。从信号捕获到完成跟踪,解码导航电文需要经历相关锁定、相位锁定、比特同步、帧同步等过程,在信号很弱以至于无法实现帧同步、不能解调卫星TOW的情况下,常规定位算法无法实现定位。文中提出多普勒与伪码相位结合的A-GPS快速定位算法,利用伪码相位值进行伪距重构法消去整数毫秒伪距中隐含的公共误差,利用多普勒定位提供的初值保证初始位置和时间误差在0.5光毫秒以内,实现了粗时间、粗位置辅助下利用多普勒与伪码相位值的A-GPS快速定位。

Research on A-GPS rapid positioning algorithm using combined Doppler and code-phase measurements

Assisted Global Positioning System provides an acquisition assistance ,ephemeris ,approx time and approx position for a A-GPS receiver through the cellular network base station to solve the weak signal positioning problem . The initial acquisition of tracking and decoding navigation message needs to go through its correlation lock ,phase lock , and the bit synchronization and frame synchronization process ,When the signal is very weak that cannot achieve frame synchronization and demodulation satellite TOW ,the conventional algorithm cannot achieve positioning solution .The A-GPS fast positioning algorithm combined with Doppler positioning and reconstructing full pseudoranges method is presented ,to reconstruct full pseudorange method to eliminate the common bias implied in integer millisecond pseudoranges .Doppler positioning solution guarantees to provide an initial position and time error less than 0.5 light-ms ,so the A-GPS rapid positioning is completed in the coarse time and rough location condition .