Estimation of Target Elevation Angles in Meter RadarsAbstract
The problem of estimating the angles of the target location in the radar meter wave range, associated with the interference of direct and reflected from the earth's surface waves. In the area of small site angles, the directional patterns for the forward and reflected waves merge together and significantly distort the estimates of the target site angles. The possibility of solving the problem of estimating the angles of the target site by three methods is analyzed: the method of angular spectral analysis, the method based on the likelihood equations, the method of maximum likelihood with high resolution, developed at the IKBFU. On the basis of the likelihood functional, expressions are derived that define the radiation patterns of the antenna system and the surface of the likelihood functional. Results of model researches of potential possibilities of estimates of angles of a place by three methods are presented. It is shown that the maximum likelihood method with a high resolution interference has no systematic errors in estimates of elevation angles, as the low correlation and the large correlation of direct and reflected waves. This method solves the problem of estimating the angles of the place in the range of 0,5 ÷ 85° with a signal-to-noise ratio of ≈ 30 dB.