典型导航信号性能分析

Performance Analysis of Typical Navigation Signals

全球卫星导航系统[1]是世界各国争相研究的首要空间基础设施,为人类提供了巨大的便利。近几年由于各种新体制的导航系统不断涌现,这些导航系统在工作时都需要一定频段的带宽。如何使有限的频谱资源合理分配给各导航系统,使其能够独立工作而又互不影响成为问题的焦点。传统的导航系统大部分采用BPSK调制[2]。但是BPSK调制使大部分功率集中在中心频点处,资源利用率不高。近几年新兴的BOC调制[3-5]的出现有效地解决了上述问题,可以使功率谱主瓣搬移到中心频率两侧。本文在分析研究BPSK调制的基础上,对BOC调制的产生原理和频谱性能进行探讨,用MATLAB分别仿真出两者的频谱图性能曲线,并对两者进行对比分析。结果表明BOC调制在一定的干扰条件下性能优于BPSK调制。

Satellite navigation system[1] is an important space infrastructure that countries all over the world compete to study, which provides great convenience for human beings. In recent years, due to the emergence of various new navigation systems, these navigation systems need a certain bandwidth in their work. How to allocate the limited spectrum resources reasonably to the navigation systems so that they can work independently without affecting each other has become the focus of the problem. Most of the traditional navigation systems use BPSK modulation[2]. However, BPSK modulation makes most of the power concentrated at the central frequency point, and the resource utilization is not high. In recent years, the emergence of BOC modulation[3-5] has effectively solved the above problems, which can move the main lobe of power spectrum to both sides of the central frequency. Based on the analysis of BPSK modulation, the generation principle and spectrum performance of BOC modulation are discussed in this paper. The spectrum performance curves of the two modulations are simulated by MATLAB and compared. The results show that the performance of BOC modulation is better than that of BPSK modulation under certain interference conditions.