针对系统要求实时在线测向的需求,提出了一种基于FPGA实现的机载阵列数字测向系统设计方案.该方案基于软件无线电的设计思想,利用了单片机实现RS接口与上位机通讯,配置系统工作参数,并设计了一种简单有效的在线自校准系统进行通道一致性校正,在FPGA中实现数据正交解调以及超分辨测向MUSIC算法.该测向系统硬件结构简单,软件参数配置灵活,测试结果表明:在快拍数不小于64点时,阵列测向误差小于0.5°,在快拍数为256点时,测向时间小于6ms,该方案能够实现MUSIC算法的准确、快速计算.
Considering the online real-time direction finding requirement for an airborne system, a scheme of airborne array digital direction finding system based on field programmable gate array (FPGA) is proposed, which implements a RS interface based on Single-Chip Microcomputer to communicate with the computer and configure system operating parameters, and designed a simple and effective online self-calibration system for channel calibration and then finishes the data quadrature demodulation and multiple signal classification (MUSIC) algorithm. The hardware struc- ture of the direction finding system is easy and software implementation is flexible. The experimental results show that the deviation is less than 0.5 degree with over 64 snapshots and the time is less 6 ms with 256 snapshots, and then the program can complete the MUSIC algorithm accurately with high speed.