两种相位鉴别器下的导航接收机跟踪环路性能分析及比较

Costas环路是导航接收机中常用的载波跟踪环路,目前关于环路性能的分析很多,传统的分析方法以及结论均是基于信号功率归一化的乘法鉴别器,且一般认为环路带宽在输入信号信噪比变化过程中是不变的。本文通过对目前数字跟踪环路实现中常用的两种鉴别器(基于总功率归一化的乘法鉴别器和反正切鉴别器)进行精确建模和分析,据此得到了两种鉴别器精确的热噪声跟踪误差表达式,并进行了仿真验证。通过比较可知,在输入信噪比小于4dB时,反正切鉴别器和归一化的乘法鉴别器的性能基本相同,两种鉴别器所能达到的跟踪门限信噪比基本相同。本文的结论可用于精确指导导航接收机的设计。

Performance Comparison of Phase Detector in Navigation Receiver's Tracking Loop

Costas loop is usually used in navigation receiver as carrier tracking loop, so many analyses have been made about coastas loop. Traditional analysis is based on unitary signal power multiplicative detector, and the loop bandwidth is considered constant no matter what the signal to noise ratio is. In this paper, two kinds of phase detectors are precisely modeled and analyzed. The pll thermal noise formula is given and proved by simulation. If the signal to noise ratio is lower than 4dB, the performances of the two detectors are almost the same, the signal to noise ratio threshold of tracking is almost the same. The results of this paper can be used to design the satellite navigation receiver.