伪码测距中处理速率对再生时钟抖动性能的影响

Effect of Processing Rate on Regenerative Clock Jitter Performance in Pseudo-Random Code Ranging

在微小卫星再生伪码测距中,码同步环的跟踪性能是决定测距精度的关键,而数字处理速率对再生时钟性能存在着影响。本文分析了再生时钟抖动性能的影响因素,并用实验验证理论分析结果。分析及实验验证表明,低测距信噪比时的再生时钟抖动主要取决于环路带宽和伪码码片速率,而在高信噪比下却受限于数字处理速率。因此,为了提升再生时钟的抖动性能从而提高再生伪码测距精度,在低信噪比下可通过降低环路带宽和提高码片速率来实现,而在高信噪比下必须提高处理速率。

The tracking performance of chip tracking loop is an important determinant of ranging accuracy in micro-satellite pseudo-random code regenerative ranging,and digital processing rate has an effect on regenerative clock jitter performance. The different factors effecting on clock jitter are analyzed and tested. The results show that at low ranging signal to noise ratio,the clock jitter depends mainly on the loop bandwidth and the chip rate. While at high ranging signal to noise ratio,the clock jitter is restricted by the digital processing rate. Therefore,in order to reduce clock jitter to improve ranging accuracy,it can be realized by reducing loop bandwidth or using high chip rate at low signal to noise ratio,while at high signal to noise ratio,the processing rate must be increased.