长基线宽带测向算法及FPGA实现

传统测向算法受到相位解模糊条件的限制，基线长度设置较短，测向精度得不到提高。为了提高测向精度，可以采用长基线，通过估计信号到达两个阵元的时间差实现方位角估计。在多相滤波信道化体制下，数据经过抽取后时间分辨率降低，运用传统的到达时间估计得到的时差精度较低。由于现代雷达发射的信号通常是宽带信号，经过时域和频域的对应关系将时差估计问题转换为频率估计问题，其精度不受采样时间间隔的限制。MATLAB和QuartusII联合仿真结果表明，该算法运算简单，适于硬件实现，可以实时进行处理。在一定的基线长度和带宽条件下，该算法能达到较高的测向精度。

Long baseline direction finding algorithm of wideband signal and its FPGA implementation

Traditional direction finding algorithms are limited by the requirement of unwrapping phase ambiguity, so the baseline length is short and the precision can＇t be improved. In order to improve the precision, the long base- line can be set. The azimuth angle can be gained by estimating the time-delay of signals between two antennas. In the channelized system of polyphase filter, the time resolution of the data is lower after the extraction and the time- delay precisions of traditional time-of-arrival estimation algorithms are worse. Because the signals launched by mod- em radars are always wideband signal, this paper converts time-delay estimation into frequency estimation according to the relationship between time domain and frequency domain. The precision of this algorithm isn＇ t limited by sampling interval. The simulation results by MATLAB and Quartus II software show that this algorithm is simple and suitable for hardware implementation. And it can be carried out in real time processing. Under the condition of cer- tain baseline length and band width, the algorithm can achieve very high orecision of direction finding.