基于正交编码的高频地波雷达信号的设计

为了避免电离层杂波折叠现象,高频地波雷达信号需要具有较大的不模糊距离,若采用简单的增大脉冲周期的方法就会使得占空比下降,而高频雷达恰恰需要高占空比信号以保证探测距离。针对这一问题,利用遗传算法来设计双脉冲正交编码,使得两个脉冲的互相关峰值低于各自的自相关峰值旁瓣,将不模糊距离推远到两个脉冲周期。为了进一步降低自相关函数旁瓣,采用反相滤波算法进行旁瓣抑制,仿真实验证明:该算法优于窗函数加权法、最小二乘法和递归最小二乘算法等失配滤波算法,且多普勒容限性高。

Signal design of high-frequency ground wave radar based on orthogonal codes

In order to avoid the ionospheric folded clutter phenomenon,high-frequency ground radar signal requires a larger unambiguous range.Increasing pulse period is simple,but it will result in the decrease of the duty-cycle.However,HFSW radar needs high duty-cycle to ensure the detection range.To solve this problem,we use genetic algorithm to design double pulse orthogonal code,making the cross-correlation peak below respective autocorrelation side-lobe peak.The un-ambiguity distance of the signal is two pulse-cycles.Furthermore,we use inverse filtering to reduce the side-lobes of the new signal.Simulation experiments show it is better than the windowing weighted method,least squares method,recursive least squares method and owns better Doppler tolerance.