星载天海中继通信载荷信号处理单元实现  

Implementation of a Signal Processing Unit for the Satellite-based Space-Sea Relay Communication Payload

作　　者：刘冕 胡一皓 王晋阳 刘才瑞 梁显锋 LIU Mian;HU Yihao;WANG Jinyang;LIU Cairui;LIANG Xianfeng(National Space Science Center,Chinese Academy of Science,Beijing 100190,China;School of Electronic Electrical and Communication Engineering,University of Chinese Academy of Science,Beijing 100190,China)

机构地区：[1]中国科学院国家空间科学中心,北京100190 [2]中国科学院大学电子电气与通信工程学院,北京100190

出　　处：《无线电工程》2022年第10期1887-1894,共8页Radio Engineering

基　　金：中国科学院战略性先导科技专项A类(XDA22030304)。

摘　　要：为了满足对远海浮标监测数据进行中继转发的需求,完成了搭载于低轨卫星的天海中继通信载荷数字基带电路单元的设计与实现。基带电路包括零中频接收模块、射频调制模块和信号处理模块。在信号处理模块内完成前向链路(载荷对海面浮标)以里德所罗门卷积级联(Reed-Solomon Convolution Concatenated,RS-CC)编码差分正交相移键控(Differential Quadrature Reference Phase Shift Keying,DQPSK)调制体制发送512 kb/s的星历数据,反向链路以7/8LDPC编码DQPSK调制体制转发接收到浮标端发送的8 Mb/s信息。载荷基带单元不仅实现上述2种数据模式的自动切换,也完成了反向链路8 Mb/s的数据接收解调。测试结果表明,基带单元发送512 kb/s和8 Mb/s速率数据时,DQPSK调制信号幅度误差和相位不平衡分别小于4%和5°;零中频解调单元实现了±50 kHz频偏时正确解调,灵敏度优于-80 dBm,动态增益可达79 dB。A design and implementation of a digital baseband circuit unit for a space-sea relay communication payload on a LEO satellite has been completed in order to meet the demand for transmitting data from distant sea buoys.The baseband circuit includes a homodyne IF receiver module,an RF modulation module and a signal processing module.In the signal processing module,the forward link(payload to buoy)transmits 512 kb/s ephemeris data in RS-CC coded DQPSK modulation regime,and the reverse link forwards the 8 Mb/s information received from the buoy in 7/8LDPC coded DQPSK modulation regime.Not only the automatic switching of two data modes in the forward link is realized,but also the data reception and demodulation in the reverse link are completed.The results show that the amplitude error and phase imbalance of DQPSK modulation signal are less than 4%and 5°when the data is transmitted at 512 kb/s and 8 Mb/s in the forward link.The correct demodulation in 50 kHz frequency offset range has been realized in the homodyne IF demodulation unit of the reverse link,the sensitivity is better than-80 dBm,and the dynamic gain is up to 79 dB.

关 键 词：低轨卫星中继通信 低密度奇偶校验码 零中频解调 差分正交相移键控 

分 类 号：TN927[电子电信—通信与信息系统]