中国空间科学技术

中国空间科学技术 ›› 2022, Vol. 42 ›› Issue (5): 44-56.doi: 10.16708/j.cnki.1000-758X.2022.0066

• 论文 • 上一篇    下一篇

Ka频段低轨遥感卫星可变编码调制应用效能研究

王中果，汪大宝，赵鹏飞，张莎莎，武小栋，张晓，王振兴   

  1. 1 中国空间技术研究院 遥感卫星总体部，北京100094
    2 西安空间无线电技术研究所，西安710071
  • 出版日期:2022-09-09 发布日期:2022-09-09

Research on variable coding and modulation application efficiency of LEO remote sensing satellite at Ka-band

WANG Zhongguo，WANG Dabao，ZHAO Pengfei，ZHANG Shasha，WU Xiaodong，ZHANG Xiao， WANG Zhenxing   

  1. 1 Institute of Remote Sensing Satellite,China Academy of Space Technology,Beijing 100094,China
    2 Xi′an Institute of Space Radio Technology,Xi′an 710071,China
  • Published:2022-09-09 Online:2022-09-09

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摘要： 分辨率的不断提高对低轨遥感卫星的星地数据传输能力提升提出了迫切需求，导致X频段星地数传通道压力急剧增加，而Ka频段可用带宽是X频段的4倍，理论上可大幅提升传输能力。当前低轨遥感卫星的星地数据传输通常采用固定编码调制（CCM）和可变编码调制（VCM），均未利用地面站仰角增大时大气衰减减小所带来的信道条件改善，对链路资源造成浪费。针对此问题，对指定地面站和链路可用度，综合考虑自由空间损耗和大气衰减随接收仰角增加而同时减小的特性，提出基于DVBS2标准的Ka频段星上VCM系统实现方案，给出传输效能评估标准,并对降雨特性不同的喀什站、北京站、三亚站CCM，VCM的Ka频段传输效能进行了对比仿真分析，以寻找出适合不同站点的星地数传方案。仿真结果表明：干旱少雨的喀什站更适合采用CCM，且链路可用度高达99.82%；雨量中等的北京站可根据用户使用需求灵活选择CCM或VCM；而降雨丰富的三亚站更适合采用VCM，不仅可将传输效能提升8.37%，还可将链路可用度提升11.23%。

关键词: 低轨遥感卫星, 可变编码调制, 应用效能, 数据传输, Ka频段, DVB-S2

Abstract: The increasing resolution of LEO（low earth orbit） remote sensing satellite puts forward an urgent demand for improving the ability of satellite-to-ground data transmission,which results in much pressure on X-band.The usable bandwidth of Ka-band is four times of X-band,which can promote the transmission capacity theoretically.At present,constant coding and modulation (CCM) and variable coding and modulation (VCM) are usually used in data transmission systems from LEO remote sensing satellites to ground stations.The improvement of channel conditions caused by the reduction of atmospheric attenuation when the elevation angle increases was not used,resulting in a waste of link resources.To solve the problem,for specific ground station and link availability,considering the characteristic that the free space loss and atmospheric attenuation decreased with the increasing of elevation angle,the VCM scheme of Ka-band based on DVB-S2（digital video broadcasting-satellite-2nd generation）was promoted,and the evaluation standard of transmission efficiency was given.The transmission efficiency of CCM and VCM at Kashgar,Beijing and Sanya stations with different rainfall characteristics at Ka-band was compared and analyzed,so as to find out the satellite-to-ground data transmission scheme for different ground stations.The simulation results show that the dry Kashgar station is more suitable for adopting CCM,and the link availability is as high as 99.82%.Beijing station with moderate rainfall is suitable for both CCM and VCM,and can be set according to users′ needs.However,Sanya station with abundant rainfall is more suitable for VCM,which not only makes the transmission efficiency factor increased by 8.37%,but also makes the link availability increased by 11.23%.

Key words: LEO remote sensing satellite, variable coding and modulation, application efficiency, data transmission, Ka-band, DVB-S2