在高动态的接收环境下,GPS接收机接收信号载频上会产生很大的多普勒频移及其变化率,传统的GPS载波跟踪环无法保证可靠的跟踪。在综合分析了常规跟踪方案的利弊后,提出一种新的基于四相鉴频(FQFD)牵引的二阶叉积自动频率控制环(CPAFC)辅助三阶锁相环(PLL)高动态跟踪环路算法。通过美国喷气推进实验室(JPL)高动态载体模型测试表明,该算法在高动态环境下不仅能快速牵入和锁定载波信号,而且在高达100g/s的加加速度作用过程中能持续、精确跟踪,实现导航电文的正常解调。
For high dynamic environment,the received signal carrier frequency can produce a large Doppler shift and rate of change,so traditional GPS carrier tracking loop can not guarantee reliable tracking.A new tracking loop algorithm is introduced,which is second-order cross-product automatic frequency control loop(CPAFC) auxiliary third-order phase-locked loop(PLL) with the traction of four-quadrant frequency discriminator(FQFD).The jet propulsion laboratory(JPL) high dynamic vector model tests show that the algorithm not only can quickly locked but also accurate tracking the carrier signal to achieve the navigation data demodulation in high dynamic environment whose jerk is up to 100 g/s.