因此，对于刚性目标，雷达散射截面的去相关是由距离和视线角的变化引起的。

Thus, for rigidtargets, decorrelation of the RCS is induced by changes in range and aspectangle.

另一方面，如果海洋表面或树林等被雷达波照射，即使雷达和目标之间没有相对运动，信号也将不相关。

On the other hand, ifnatural clutter such as the ocean surface or a stand of trees is illuminated,the signature will decorrelate even if the radar and target do not moverelative to each other.

在这种情况下，去相关是由杂波的“内部运动”引起的，例如海面上的波浪运动或树叶和枝条的晃动。

In this case thedecorrelation is caused by the "internal motion" of the clutter, suchas the wave motion on the sea surface or the blowing leaves and limbs of thetrees.

去相关速率受雷达外部因素的影响，如风速等。

The rate ofdecorrelation is influenced by factors external to the radar such as windspeed.

距离或视线的变化也会引起杂波信号的去相关。

Range or aspectchanges also induce decorrelation of clutter signatures.

虽然实际目标的特性可能非常复杂，但通过以下简单的论证，可以获得目标或杂波块去相关所需的频率或角度变化量的有用估计。

Although the behaviorof real targets can be quite complex, a useful estimate of the change infrequency or angle required to decorrelate a target or clutter patch can beobtained by the following simple argument.

考虑一个目标，该目标由均匀线阵的点散射体组成，点散射体相对于天线视距以θ角度倾斜，相邻点散射体之间的距离为Δx，如图2.12所示。

Consider a targetconsisting of a uniform line array of point scatterers tilted at an angle θwith respect to the antenna boresight and separated by Δx from one another, asshown in Fig. 2.12.

Figure 2.12. 用于计算RCS去相关频率和视线角间隔的几何结构示意图Geometry for calculation of RCS decorrelation interval in frequencyand aspect angle.

假设该目标包含2M+1奇数个散射体，索引范围为–M到+M，如上图所示。

Assume an odd number 2M + 1 of scatterers indexed from –M to+M as shown.

则总的目标长度为L = (2M +1)Δx。

The total targetextent is then L = (2M + 1)Δx.

——本文译自Mark A. Richards所著的《Fundamentals of Radar Signal Processing（Second edition）》

更多精彩文章请关注微信号：