辅助型GPS接收机中伪码相位延时及其不确定度估计算法研究

Estimate Algorithm for Pseudo-code Phase Delay and its Uncertainty in the Assisted GPS Receiver

快速捕获卫星信号是研制辅助型GPS(A-GPS)接收机所必须解决的一项关键技术.针对A-GPS接收机能从辅助数据中获取有效星历的特点,本文提出了一种伪码相位延时及其不确定度估计算法.该算法在对建立的信号发射时刻方程泰勒展开的基础上,利用辅助信息建立了伪码相位延时及其不确定度估计方程.分析和仿真表明,提出的算法能有效压缩剩余卫星伪码相位延时不确定度,加快A-GPS接收机的捕获速度.

Quick acquisition of satellites signals is a key technology in the assisted GPS （A-GPS） receiver. Considering that the A-GPS receiver can obtain the valid ephemeris data from the assistance data, a new estimate algorithm for pseudo-code phase delay and its uncertainty are proposed. On the basis of the Taylor approximation for the time of GPS signal transmission function, the estimate equation of pseudo-code phase delay and its uncertainty are proposed by using the assistance data. Simulation and experimental results show that the proposed algorithm can effectively compress the uncertainty of pseudo-code phase delay to the rest satellites, and can accelerate the signal acquiring speed of A-GPS receiver. As for the conventional un-assisted GPS receiver, the pseudo-code phase delay and its uncertainty can also be well estimated by the algorithm proposed in the paper when effective ephemeris data, satellite clock bias and pseudo-range amendment information are pre-stored in the receiver.