卫星通信中定时误差检测改进算法

符号定时同步技术是卫星通信系统的关键技术之一，其准确性会直接影响整个系统的性能。鉴于Gardner算法在定时同步环路中的广泛应用及其对限带信号的局限性，在异步采样同步思想的基础上，通过对Gardner算法及其修正算法在式样抖动及定时误差方面的比较，提出了一种增强的Gardner定时误差检测算法(E-Gardner)。该算法结构简单，且能有效地减小定时误差偏差和系统自噪声。仿真结果表明，在Suzuki移动卫星信道环境下，E-Gardner算法在小滚降系数情况下对正交相移键控（quadrature phase shift keying, QPSK）调制信号的时钟捕获及误差检测的性能有明显的改善。

Improved timing error detection algorithm in satellite communication

The symbol timing synchronization technology is one of the key technologies of the satellite communication system, whose accuracy directly affects the performance of the entire system. In view of the wide application of the Gardner algorithm in timing synchronization loop and its limitation of the band limited signals, an enhanced Gardner timing error detection algorithm(E-Gardner),which has a simple structure and can effectively reduce the deviation of the timing error and system self-noise, is proposed by the comparison of the Gardner algorithm and its correction algorithm in terms of the pattern jitter and timing errors on the basis of the asynchronous sampling. The simulation results show that E-Gardner algorithm has a significant improvement in the performance of QPSK modulation signal’s clock capture and error detection in the case of a small roll off factor under the Suzuki mobile satellite channel.