卫星可变编码调制系统设计与验证

Design and Verification of Satellite Variable Coding Modulation System

可变编码调制系统(VCM)具备改变编码方式、调制方式、速率的能力,十分适合低轨卫星使用。文章根据我国遥感卫星主要依靠地面站完成数据接收,其接收仰角大范围变化的特点,设计了卫星可变编码调制的系统方案,分析了工作流程、切换门限、物理层帧格式等参数,说明了可变编码调制器的设计方案和实现结果。目前,该方案已在高分七号卫星上完成了可变编码调制系统的在轨试验验证。在轨试验结果表明:传输速率相对于固定编码调制系统(CCM)提升了30%,显著提升了高分七号卫星的星地数传链路的传输能力。

Variable Coding Modulation(VCM)has the ability to change coding,modulation,and rate,making it suitable for LEO satellites.Considering that Chinese remote sensing satellites mainly use ground stations to receive data which brings a large-range change of the elevation angle during the data transmission period,a VCM system is designed.The workflow,switching thresholds as well as the physical layer framing are analyzed,and then the scheme and results of VCM modulator is illustrated.The system has been implemented and verified onboard GF-7 satellite.The results indicate that compared with Constant Coding Modulation(CCM)system,VCM increases the transmitted bit rate by 30%,which significantly improves the satellite-Earth data transmission link capacity of GF-7 satellite.