基于脉冲调制的共频带定位系统抗远近效应研究  

Suppression of Near-far in CO-BAND Positioning System on Pulse Modulation

作　　者：张昌良 吴华兵[1,2] 武建锋 ZHANG Chang-liang;WU Hua-bing;WU Jian-feng(National Time Service Center,Chinese Academy of Sciences,Xi'an 710600,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院国家授时中心,西安710600 [2]中国科学院大学,北京100049

出　　处：《宇航计测技术》2023年第3期91-96,共6页Journal of Astronautic Metrology and Measurement

基　　金：中国第二代卫星导航系统重大专项(ZFS20001D(03));中国科学院青年创新促进会项目(2019399)资助。

摘　　要：在共频带定位系统中由于远近效应的影响,近场强定位信号可能对远场弱定位信号形成压制干扰,导致远场信号无法被捕获,进而影响系统的定位精度。针对该系统存在的远近效应问题,本研究利用脉冲调制法对其进行抑制。首先,分析了远近效应产生的原因;其次,对脉冲调制的关键参数占空比和脉冲图案设计进行了深入研究,设计得到了一种适用于本系统的脉冲调制方案;最后,从理论和仿真两方面对所设计的脉冲调制方案进行性能分析。仿真结果表明:在经过脉冲调制后,受到远近效应影响的弱信号被捕获的概率大幅提升;同时,在强弱信号功率比为40dB以内时,使用脉冲调制技术可以有效的改善弱信号捕获性能。In the CO-BAND Positioning System,due to the far-near effect,the strong near-field positioning signal may suppress the far-field weak positioning signal,resulting in the far-field signal not being captured and thus affecting the positioning accuracy of the system.To address the problem of far-near effect in this system,the article adopts pulse modulation method to suppress it.Firstly,the causes of the far-near effects are analyzed;secondly,the key parameters of pulse modulation,duty cycle and pulse pattern design,are studied in depth,and a pulse modulation scheme applicable to the system is designed;finally,the performance of the designed pulse modulation scheme is analyzed from both theoretical and simulation aspects.The simulation results show that after pulse modulation,the probability of capturing weak signals affected by the near-far effects is greatly improved;meanwhile,the use of pulse modulation technique can effectively improve the weak signal capture performance when the power ratio of strong and weak signals is 40dB or less.

关 键 词：共频带定位系统 脉冲信号 远近效应 通导融合 

分 类 号：TN96[电子电信—信号与信息处理]