星间链路通信收发一体化系统设计

Design of Inter-satellite Link Communication Transceiver Integrated System

摘要:

随着卫星制造发射成本的降低以及全球通信需求的增加，低轨星间链路技术成为研究热点。星间链路可将多颗卫星互联，建立具有导航和通信功能的自主运行系统，可靠的通信技术是当前的研究重点。为了适应外太空具有较大多普勒频移的高动态环境，设计了星间链路通信收发一体化系统。发射端采用UQPSK直接序列扩频技术，双通道架构可同时完成不同速率的导航与通信数据的发射，再运用LDPC编码技术提升数据发射速率与稳定性；接收端采用改进的PMF-FFT分段捕获算法与归一化最小和LDPC译码算法，以快速准确捕获星间信息。在FPGA硬件平台经过多次测试，该系统均可在高动态环境下，正确快速捕获到多普勒频移高达 341KHz的信号，捕获算法时间均可保持在200ms以内，符合实际应用中的性能需求。

Abstract:

With the reduction of satellite manufacturing and launch costs and the increase in global communication needs, low-orbit Inter-satellite link technology has become a research hotspot. The Inter-satellite link can interconnect multiple satellites to establish an autonomous operating system with navigation and communication functions, reliable communication technology is the current focus of research. In order to adapt to the highly dynamic environment with large Doppler frequency shift in outer space, an integrated inter-satellite link communication transceiver system was designed. The transmitter uses UQPSK direct sequence spread spectrum technology, the dual-channel architecture can simultaneously complete the transmission of navigation and communication data at different rates, and then uses LDPC encoding technology to improve the data transmission rate and stability; The receiving end uses an improved PMF-FFT segmented acquisition algorithm and a normalized minimum sum LDPC decoding algorithm to quickly and accurately capture inter-satellite information. After many tests on the FPGA hardware platform, the system can accurately and quickly capture signals with Doppler frequency shift up to 341KHz in highly dynamic environments. The capture algorithm time can be kept within 200ms, which meets the performance requirements in practical applications.