扩频接收机的载波捕获跟踪算法的优化与实现  

Optimization and Implementation of Carrier Acquisition and Tracking Algorithm in Spread Spectrum Receiver

作　　者：徐一红[1] 郭胜召[1] XU Yihong GUO Shengzhao(School of Mechanic and Electronic Engineering, Shandong Management University, Jinan 250357, Chin)

机构地区：[1]山东管理学院机电学院,山东济南250357

出　　处：《济南大学学报（自然科学版）》2017年第4期358-363,共6页Journal of University of Jinan(Science and Technology)

基　　金：国家社会科学基金项目(16BGL181);山东省社会科学规划项目(16CGLJ21);山东省高校科技发展计划项目(J13LC51);山东省科技厅星火计划项目(2011XH17006);济南市高校院所自主创新计划项目(201401213)

摘　　要：提出一种基于现场可编程门阵列的数字化扩频接收机的设计方案,并针对接收机中的捕获跟踪算法进行优化和实现;捕获过程分析采用基于快速傅里叶变换并行相关的方案;跟踪环路中采用二阶锁频环(FLL)辅助三阶锁相环(PLL)的载波跟踪环路,以实现在高动态环境下的载波同步;引入判决因子,调整FLL的断开时机,提出带宽调整的策略优化跟踪环路以提高跟踪环路的准确性。结果表明,在信号的信噪比为5 d B,码速率为1 kbps,多普勒频偏为±2 MHz,加速度为±800 Hz/s时,频率估计误差小于1 Hz,实现了高动态的微弱信号精确捕获跟踪。A design scheme of digital spread spectrum receiver based on FPGA was presented, and a acquisition and tracking algorithm in receiver was optimized and implemented. In the acquisition process, the carrier capture scheme based on FFT was analysed and implemented. The second order frequency-locked loop （FLL） auxiliary third order phaselocked loop （PLL） carrier tracking loop was used to realize the carrier frequency synchronization in high dynamic environment. The decision factor was introduced to adjust the timing of disconnecting FLL. The loop filter bandwidth was adjusted to improve the accuracy of the tracking loop. The results show that when the slgnal-to-noise ratio is 5 dB, doppler frequency offset is ± 2 MHz, and accelerated speed is ± 800 Hz/s, the signal frequency estimation error is less than 1 Hz, which can achieve the accurate acquisition and tracking of high dynamic weak signals.

关 键 词：捕获算法 跟踪算法 锁相环 锁频环 

分 类 号：V443.1[航空宇航科学与技术—飞行器设计]