去除地面反射波的波达角估计方法研究

DOA estimation algorithms eliminating ground reflected waves

以基于极化平面的波达角(Direction of Arrival,DOA)估计算法为基础,针对近地面天线受地面反射波影响从而极大地影响DOA估计的准确性问题,对如何去除地面反射波的影响进行深入研究.分别采用理想地面近似法、反射系数法和阵列抑制算法进行仿真试验,对比和分析这三种算法的优缺点,以及各自的适用性.理论分析和仿真试验表明:理想地面近似算法在实际地面参数与理想导电平面相近时,具有准确的计算结果,但在其他情况下计算结果与真实值误差很大;反射系数法通过地面的电导率σ、相对介电常数εr以及入射波的极角θ分别求出地面的水平反射系数和垂直反射系数,从而准确估算出来波方向,但由于该方法需要预先知道地面参数,故其应用场景受到了一定的限制;阵列抑制算法巧妙地利用地面反射波和直达波在相位延迟和入射角方面的关系,通过移相操作,生成抑制反射波的新数据,再对其进行处理,准确计算出DOA.通过比较分析可以得出,阵列抑制算法可用于任何类型的实际地面,且无需知道实际地面参数,同时该算法具有很好的准确性,因此其应用场景不受限制,具有很好的理论研究和实际应用价值.

and thus the accur solve the problem that the near ground acy of the direction of arrival（DOA） is based DOA estimation algorithm to eliminate the effec the ideal ground approximation, reflection coefficient and compared merits and faults, and the applicability mation has a good computation result when the actual plane parameters. the horizontal and lectric constant er ters in advance so antenna is affected by the ground reflected wave, greatly reduced, we studied a polarization plane t of ground reflect method of them. and array We find ground parameters ed wave. We used three methods, inhibition algorithm to simulate, out that the ideal ground approxi- are similar to the ideal conducting While in other cases, errors are very large, In reflection coefficient method, we obtained vertical reflection coeff and incident polar angle icients of the ground from elect 0. But this algorithm needs to rical conductivity a, relative die- know the actual ground parame- that the application scenarios are limited. The array inhibition algorithm skillfully usesthe relationships between the direct arrival wave and the ground reflected wave in phase delay and incident polar angle. We can get the new data without the ground reflected wave by shifting phase. Through this new data, the direction of arrival of the incident electromagnetic wave can be calculated accurately. By comparison and analysis, we draw a conclusion that the array inhibition algorithm can be used for any kind of actual ground and we do not need to know the actual ground parameters in advance, and the accuracy of this algorithm is also high. Thus, its application scenarios are not limited and it has large application value.