空分天线风场测量中三角尺寸效应的抑制

利用空分天线方法进行风场测量时存在着三角尺寸效应,以往公认的产生原因包括电子噪声干扰、地杂波等因素.本文首先提出另外一种产生三角尺寸效应的可能原因,即大气非平稳性和不均匀性(可统称为大气非平稳性),并讨论了由于此原因对大气风场测量的影响和作用以及产生三角尺寸效应的具体机制.在此基础上提出了一种用来消除大气的非平稳性影响的方法,即增量累积量法.用增量累积量方法的特例(2阶零延迟增量累积量)得出一维平均速度的表达式.理论分析表明利用该方法还可以有效地去除地杂波效应;高阶(k≥3)情况,增量累积量还可以抑制高斯噪声.分别在非平稳大气情况和有地杂波情况下,对空分天线方法中的全相关分析算法和增量累积量法进行数值模拟对比,得出结论:随着天线间距的变化,增量累积量法实测平均风场水平速度与模型输入速度的偏差比全相关分析算法要小得多.

The Suppression of Triangle Size Effect in Spaced Antenna Wind Measurements

There is the Triangle Size Effect （TSE） in wind measurements with Spaced Antenna （SA） method due to electronic noise and ground clutters etc. Another possible cause （non-stationary of atmosphere） of TSE and the mechanism of its effect to wind measurements was discussed in this paper. The work also presents Increment＇s Cumulant Approach （ICA） to eliminate the nontationary of atmosphere and ground clutter based on the analysis of the causes of TSE; the analytical expression of one dimension mean velocity can also be obtained by the special case of Increment＇s Cumulant Approach （the 2nd order zero-lags ICA）. In addition the high order （k ≥ 3） cumulant of increment are proposed to suppress Gaussian noise. The comparisons between FCA and ICA with non-stationary and ground clutter by numerical simulations show that the measurement errors of ICA are much less than those of FCA by comparing mean horizontal velocities （output of simulations） and input velocities of mode.