跳频对DS／FH接收机载波跟踪精度影响分析

面对日益复杂的电磁环境,将DS/FH混合扩频技术引入航天测控领域是一种尝试.针对DS/FH信号的特点,推导了航天测控背景下的DS/FH混合扩频系统接收机关键节点的数学模型,分析了航天测控应用中由于DS/FH混合扩频信号的相邻跳频频率不同导致附加在载波上的多普勒频率跳变和载波初始相位跳变对混合扩频接收机捕获跟踪的影响,重点分析了载波多普勒频率跳变和载波初始相位跳变对接收机载波跟踪精度的影响;提出了一种减小由于跳频载波初始相位不确定造成相关累积能量损失的方法,并利用跳频图案辅助降低了跳频对混合扩频接收机载波跟踪精度影响,仿真验证了该方法的有效性.

Impact analysis on frequency hopping to carrier tracking precision in DS/FH hybrid spread spectrum receiver

Facing the increasingly complex electromagnetic environment,it is an attempt to introduce DS/FH hybrid spread spectrum technology to the field of TT&C.According to the characteristics of DS/FH signal,mathematical model of several key nodes in DS/FH hybrid spread spectrum receiver was derived in the context of TT&C.Effect to acquisition and tracking in the hybrid spread spectrum receiver caused by hopped Doppler frequency and initial carrier phase transition attached to the carrier brought by adjacent hopped frequency’s difference was analyzed,especially effect to carrier tracking precision.A method to lower the accumulated energy loss caused by initial carrier phase uncertainty of hopped carrier was proposed.The receiver employed hopping pattern to reduce the impact of hopped frequency to tracking precision in the DS/FH hybrid spread spectrum receiver,and the effectiveness of the method was verified through simulation.