双基MISO地波雷达中的距离-方位耦合及解耦研究

双基多输入单输出(multiple input single output,MISO)地波雷达采用岸基均匀线阵发射多载频线性调频中断连续波FMICW信号,单根全向天线接收回波信号。由于各发射阵元所用载频不同,目标回波中存在距离-方位耦合。耦合严重时,空时超分辨算法将失效。借鉴比幅单脉冲测角思想,推导了该耦合关系,得到耦合系数以及影响该系数的因素,即阵元发射信号载频与阵元位置。利用遗传算法优化载频选择方案,从而对距离方位解耦以提高测距测角精度。仿真表明通过合理选择阵元发射信号载频可以有效去耦。

Study of range-azimuth coupling and decoupling in bistatic MISO surface-wave radar

Bistatic MISO surface-wave radar uses an array located along a coast to transmit the FMICW signals of multiple carrier frequencies and uses a single antenna to receive the returns.The range-azimuth coupling occours due to the fact that the carrier frequency at each of the transmit elements is different one another.For serious coupling,the space-time supresolution method doesn’t work.The coupling is deduced based on the amplitude comparison monopulse and the coupling coefficient is obtained,which is dependent on both the carrier frequency an antenna emits and the position it locates.The problem of selecting the optimum frequency code for range-azimuth decoupling is solved by the genetic algorithm and the resultant measurment accuracy is improved greatly.The computer simulation proves that the decoupling can be solved by proper permutation of the carrier frequency.