Elevation angle estimating method of multi-frequency fusion maximum likelihood low-altitude target

The invention discloses an elevation angle estimating method of a multi-frequency fusion maximum likelihood low-altitude target mainly to solve the problem that in the prior art, estimation to the elevation angle of a low-altitude target under multi-path environment is large in error. The elevation angle estimating method comprises the steps of (1) conducting sampling to multiple sets of pulse intermediate multi-frequency back waves received by a radar to obtain sampling data; (2) computing sampling covariance matrixes of all frequency points by the utilization of the sampling data; (3) arranging the sampling covariance matrixes along diagonal lines to obtain a multi-frequency composite sampling covariance matrix; (4) constructing projection matrixes of all the frequency points; (5) obtaining a multi-frequency composite projection matrix by the utilization of the projection matrixes; (6) conducting spatial spectrum two-dimensional angle optimization by the utilization of the multi-frequency composite sampling