应用于校射弹的扩频接收机设计方法

Design of spread spectrum receiver based on correction firing projectile

为实时检测弹丸运动参数,弥补传统校射手段的不足之处,给出一种应用于校射弹的扩频接收机的设计方法。捕获过程采用基于快速傅里叶变换（FFT）并行捕获的方案,并根据项目要求,优先进行载波捕获,且采用FFT补零法对捕获算法进行优化;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,采用门限判决,提出调整FLL与PLL切换时机的策略,优化跟踪环路以提高跟踪环路的准确性。最后对主要的系统性能进行分析,并利用仿真验证。仿真结果表明,在中频放大后信号的信噪比为-36 dB,码速率是1 kbps,多普勒频偏±10 kHz,以及多普勒频移加速度±500 Hz/s时,频率估计误差小于10 Hz,实现了接收高速度运动载体发射信号的功能。

The simulation design of spread spectrum receiver based on correction firing projectile was given for the real-time detection of the projectile motion parameters, which expected to improve the deficiencies of traditional methods. In the acquisition process, the carrier capture scheme based on FFT was analyzed and implemented. In the tracking loop, the second order frequency-locked loop（FLL） was used to assist the carrier tracking loop of third order phase-locked loop（PLL）.The decision conditions are introduced to adjust the timing of FLL and PLL switching, and a strategy optimization tracking loop is proposed to improve the accuracy of the tracking loop. The results show that when the signal-to-noise ratio is-36 dB, code rate is 1 kbps, Doppler frequency offset is ±10 kHz,and accelerated speed is ±500 Hz/s, the signal frequency estimation error is less than 10 Hz,which can achieve the function of receiving high speed moving carrier transmitting signal.