基于码元同步环路的激光测距通信一体化算法优化研究

Research on the optimization of the integrated algorithm of laser ranging and communication based on the symbol synchronization loop

摘要:

精密测距与高速通信一体化技术已发展成为星间激光链路的主要研究方向之一。为了探究基于空间激光通信系统的通信解调算法对测距性能的影响机理，根据现有的激光通信系统架构，分析了测距通信一体化系统的工作原理，搭建了基于码元同步的激光测距通信一体化系统模型，分析了基于Gardner同步环路信号跟踪系统的测距精度，并对鉴相算法进行了优化。理论和仿真证明，优化后的码元同步环能够同时实现码元同步判决和距离解算，并得到了4 dB的噪声容忍度提升，其测距方差主要与基带成型滤波参数、环路带宽、载噪比以及鉴相增益等因素有关。该算法简洁，不受载波相位影响，对高阶调制具有良好的兼容性，适用于空间激光链路系统，丰富了测距通信一体化理论，为后续一体化系统设计提供了仿真依据。

Abstract:

The integrated technology of precision ranging and high-speed communication has developed into one of the main research direction of inter-satellite laser links. In order to explore the influence mechanism of the communication demodulation algorithm based on the space laser communication system on the ranging performance, according to the existing laser communication system architecture, this paper analyzes the working principle of the integrated system of ranging and communication, and builds a laser based on symbol synchronization. Based on the integrated system model of ranging and communication, the ranging accuracy of the signal tracking system based on Gardner synchronous loop is analyzed, and the phase detection algorithm is optimized. Theory and simulation prove that the optimized symbol synchronization loop can realize symbol synchronization judgment and distance calculation at the same time, and obtain a 4 dB noise tolerance improvement. The ranging variance is mainly related to baseband shaping filter parameters, loop bandwidth, carrier noise. It is related to factors such as ratio and phase detection gain. The algorithm is simple, not affected by the carrier phase, has good compatibility with high-order modulation, and is suitable for space laser link systems. The system model and algorithm proposed in this paper enrich the theory of ranging and communication integration, and provide simulation basis for the subsequent integrated system design.