一种改进的复合型弱信号载波跟踪方法研究

Research on an Improved Composite Carrier Tracking Method for Weak Signal

论述了使用FFT跟踪载波的方法。在标准锁相环(PLL)的基础上引入平方检测器,形成了一种更先进的跟踪结构——非相干模块处理跟踪环路(NCBP)。并对此环路进行改进,提出了使用FFT和非相干模块处理跟踪环相结合的复合软环跟踪GPS微弱信号的方法。通过模拟微弱GPS接收信号,从跟踪精度、环路锁定速度和环路的动态应力性能等方面比较了几种载波跟踪环的性能。仿真结果表明:该复合软环可以提高环路跟踪精度和锁定速度,它的等效噪声带宽可以设得更小,减小引入到环路的噪声,提高环路稳定性。

This paper discusses the use of FFT tracking carrier method. A squaring detector is introduced on the basis of the standard PLL, coming into being a more advanced tracking structure which is non-coherent block processing （NCBP） architecture. This loop is proposed using FFT and NCBP combination of complex soft-loop tracking weak GPS signal. The performance of several carrier tracking loops in the aspects of tracking errors, loop lock speed and loop dynamic stress performance by simulating the received GPS weak signal. The application shows that this complex soft-loop can improve loop tracking errors and lock speed, its equivalent noise bandwidth can be set smaller to reduce the noise introduced into the loop, and to improve the loop stability.