量子科学实验卫星射频信道物理层设计

量子科学卫星有效载荷激光链路需要有一条上下行射频高速通信链路作为激光链路的量子秘钥分发途径.构建了量子科学卫星上下行射频链路的物理层硬件和算法，该链路采用符合CCSDS频谱规范的SRRC-OQPSK作为上行调制类型，上行速率达到1.024Mbit·s-1，下行采用SRRC-OQPSK和GMSK调制，速率达到4Mbit·s-1.经过与多个地面站的对接试验测试，结果表明数传通信机的载波捕获灵敏度优于-100dBm，数据解调灵敏度优于-98dBm，AGC（自动增益控制）能力大于43dB，在-96dBm接收信号电平条件下的实际传输误码率优于1×10-9.在轨试验验证证明，射频信道物理层设计方案满足量子科学实验任务要求. 

Physical Layer Design of Microwave Communication Link for Quantum Science Experiment Satellite

In order to ensure quantum science experiments can be developed smoothly, a high data rate two-way link for Space-Ground microwave communication must be established. By following the study on Consultative Committee for Space Data Systems (CCSDS) and taking into account the scientific requirements of microwave communication link for quantum science experiment satellite, the physical layer hardware architecture and modulation/demodulation algorithm of microwave communication link for the satellite are presented. The uplink modulation type of the microwave communication link is SRRC-OQPSK, which is accordance with CCSDS spectrum standard. The specification of uplink data rate is 1.024Mbit·s-1. The downlink modulation type of the microwave communication link is SRRC-OQPSK/GMSK, and the data rate is 4Mbit·s-1. By compatible tests with several ground stations, it is found that the sensitivity of carrier acquisition is superior to -100dBm, and AGC (Automatic Gain Control) ability is greater than 43dB. Moreover, the bit error rate of actual transmission is superior to 1×10-9 as the received signal level is equal to -96dBm. The in-orbit verification indicates that the physical layer design scheme of microwave communication link meets the requirements of space quantum science experiments.