“北斗”B2频段导航信号伪码跟踪性能分析

Pseudo Noise Code Tracking Performance Analysis of Beidou B2 Frequency Band Navigation Signal

与传统卫星导航信号体制不同,新一代"北斗"B2频段导航信号采用了交替二进制偏移载波调制(Alt BOC)体制,因此伪码跟踪性能也与传统信号体制有较大差异。首先介绍了Alt BOC调制信号原理及特点,然后根据码跟踪精度理论比较了新型调制信号与传统信号体制的性能差异,分析了不同鉴相器时B2频段信号的码跟踪误差,并对不同相关器间隔、环路带宽、前端带宽、载噪比环境条件下的伪码跟踪误差进行了仿真分析。仿真结果表明,提高信号载噪比、射频前端带宽或减小相关器间隔、环路带宽均能减小码跟踪误差。研究结果对新一代"北斗"导航信号新体制性能的评估以及"北斗"导航接收机的系统设计具有一定指导意义。

Different from the traditional satellite navigation system signal, the new generation of Beidou B2 frequency band navigation signal adopts the alternative binary offset carrier（ AltBOC） modulation, so the per-formance of pseudo noise（PN） code tracking is different from the traditional signal system. Firstly, the prin-ciple and charateristics of AltBOC modulation signal are introduced. Then, according to the theory of code tracking precision,the performance difference is compared between the new modulation signal and the tradi-tional signal,and the code tracking error of B2 frequency band signal is analyzed in different phase detectors. Finally,simulation analysis of PN code tracking error is also carried out under different correlator interval,loop bandwidth, front-end bandwidth, carrier to noise ratio conditions. Simulation results show that code tracking er-ror can be reduced by improving the carrier to noise ratio and the RF front-end bandwidth,or decreasing the correlator interval and the loop bandwidth. The research results are significant for evaluating the performance of the new generation of Beidou navigation signal and the design of Beidou navigation receivers.