调制比对低频时码信号传输性能的影响分析

Analysis of the influence of modulation ratio on the transmission performance of low⁃frequency time code signals

低频时码授时系统是我国综合PNT体系中重要的组成部分,信号简单,接收成本低廉,在民用领域被广泛应用。该文针对我国低频时码授时系统信号覆盖范围不足的情况,提出了提高低频时码信号的调制比来提高其覆盖范围的思路。在分析我国低频时码授时系统现有信号体制的基础上,对调制比对低频时码传输性能的影响进行重点研究,通过理论分析和仿真模拟并通过米林顿方法计算了调制比改进前后的低频时码覆盖半径,验证了提升调制比可以提升低场强下接收机的接收和解调能力,且其覆盖范围有所提升,为进一步改进我国低频时码信号体制打下基础。

The low⁃frequency time code timing system is an important part of my country’s comprehensive PNT system.The signal is simple,the receiving cost is low,and it is widely used in the civilian field.Aiming at the lack of signal coverage of low⁃frequency time⁃code timing systems in my country,this paper proposes an idea to improve the modulation ratio of low⁃frequency time⁃code signals to improve its coverage.On the basis of analyzing the existing signal system of low⁃frequency time⁃code timing system in our country,the influence of modulation ratio on the transmission performance of low⁃frequency time⁃code is mainly studied.The low⁃frequency time code coverage radius before and after the modulation ratio improvement is calculated by theoretical analysis and simulation and through the Millington method,and it is verified that the enhancement of the modulation ratio can improve the reception and demodulation ability of the receiver under low field strength,and its coverage is improved.It lays the foundation for further improvement of my country’s low⁃frequency time code signal system.