引入微分控制思想的辅助GPS载波跟踪环路设计

摘要

载波信号跟踪环路制约着GPS接收机的工作性能,针对其易受高动态和弱信号等环境干扰的缺陷,提出一种引入微分控制思想、应用SINS辅助接收机载波跟踪环路的设计方法.剖析应用于载波跟踪的相位锁定环(Phase Locked Loop,PLL),并将其近似为PI控制模型；在验证辅助信息引入时环路系统稳定的基础上,增加类微分控制项,利用SINS的输出和时钟误差信息估算的多普勒频率作为跟踪环路的中心频率,辅助PLL实现载波信号跟踪；仿真结果表明提出方法能够有效地缩短跟踪环路带宽,缓解热噪声和动态应力之间的矛盾,进而改善载波环路的频率响应和跟踪误差.%The performance of GPS receiver is affected by carrier tracking loop. Because of the vulnerability of carrier tracking in high dynamic and weak signal environments,a method of strapdown inertial navigation system (SINS) aiding GPS tracking loop utilized differential control cogitation is proposed.Phase locked loop (PLL) utilized in traditional carrier tracking is analyzed, and the control mode could be considered as PI (proportion and integration) control. Then the stable of tracking loop with information aiding is verified, and differential control item is introduced to achieve carrier tracking, where the Doppler prediction is calculated by SINS output and clock error. Simulation results indicate that the proposed method could shorten the bandwidth of tracking loop, relieve the contradiction between thermal noise and dynamic stress, and thus further improve the frequency response and tracking errors in carrier tracking loop.