深空干涉测量天线G/T指标设计

Design and Analysis of the G/T Value of Deep Space Interferometry Antennas

G/T是天线的一项重要技术指标,在综合考虑测地VLBI(Very Long Baseline Interferometry,甚长基线干涉测量)和航天器VLBI观测两者需求的基础上,提出了深空干涉测量天线的G/T指标设计方法。首先根据射电源的空间分布以及流量密度特性,确定了测地VLBI和航天器VLBI观测模式下射电源流量密度的要求。在此基础上建立了2种观测模式下时延误差与深空干涉测量天线G/T之间的关系模型。最后参考目前国际国内测地VLBI观测中的通用参数设置以及月球探测任务中航天器VLBI观测的参数设置,对不同观测任务、不同观测模式下的G/T要求进行仿真分析。综合测地VLBI和航天器VLBI观测仿真分析的结果,S频段G/T建议不小于32dB/K,X频段G/T建议不小于43dB/K。仿真分析结果可以作为后续深空干涉测量天线G/T设计的参考。

The demands of flux density in geodetic VLBI（Very Long Baseline Interferometry）observation and spacecraft VLBI observation are determined according to the characteristics of geodetic VLBI observation and spacecraft VLBI observation in combination with the distribution and flux density characteristics of radio sources.Model between delay error and G/T value of deep space interferometry antenna is established based on the basic principle of radio sources and spacecraft VLBI observation.Simulation of the G/Tvalue in different observation missions and different observation types are done,where the parameters are a stimulus to the parameters in international geodetic VLBI observation and spacecraft VLBI observation of Chang＇E mission.The results show that the G/Tvalue of S band should be larger than 32dB/K,and that of X band should be larger than 43dB/K.The principle and simulation results are of some significance to G/Tvalue designing and analysis of deep space interferometry antennas.