A method for estimating a height of an object , carried out by a detection device that transmits a wave signal (S t ) to be reflected by the object and receives, by a plurality of receiver antenna elements (11A, 11B,...), wave signals (S r1 , S r2 , ...) reflected by the object , the wave signals propagating via a direct path between the object and the detection device and an indirect path between the object and the detection device via reflection over a reflecting surface , said method including the steps of: - measuring (S1, S2) the received reflected wave signals (S r1 , S r2 ) to determine measurement information from the plurality of receiver antenna elements (11A, 11B,...) and generating a measurement vector (V(t n )) of complex values, said measurement vector including the determined measurement information from the plurality of receiver antenna elements (11A, 11B, ...) as respective vector components, at successive measurement points (t n ) in time; and, while a range (R) between the detection device and the object varies (S3) over time: - producing (S43) an energy spectrum of an estimated elevation angle (θ) of the object for the range ( R ( t n )) at each of the successive measurement points in time (t n ), by combining a plurality of measurement vectors over a sliding range window (W); and - estimating (S44, S45) the height (h 2 ) of the object from the produced energy spectrum of the estimated elevation angle (θ); wherein, the length (ω) of the sliding range window (W) is variable and determined (S42) by estimating the range interval covered by a full phase cycle of a phase difference between the direct path and the indirect path, from a current value of the range (R) and a current estimate (h 2 ) of the height of the object . said method including the steps of: - measuring (S1, S2) the received reflected wave signals (S r1 , S r2 ) to determine measurement information from the plurality of receiver antenna elements (11A, 11B,...) and generating a measurement vector (V(t n )) of complex values, said measurement vector including the determined measurement information from the plurality of receiver antenna elements (11A, 11B, ...) as respective vector components, at successive measurement points (t n ) in time; - measuring (S1, S2) the received reflected wave signals (S r1 , S r2 ) to determine measurement information from the plurality of receiver antenna elements (11A, 11B,...) and generating a measurement vector (V(t n )) of complex values, said measurement vector including the determined measurement information from the plurality of receiver antenna elements (11A, 11B, ...) as respective vector components, at successive measurement points (t n ) in time; and, while a range (R) between the detection device and the object varies (S3) over time: - producing (S43) an energy spectrum of an estimated elevation angle (θ) of the object for the range ( R ( t n )) at each of the successive measurement points in time (t n ), by combining a plurality of measurement vectors over a sliding range window (W); and - estimating (S44, S45) the height (h 2 ) of the object from the produced energy spectrum of the estimated elevation angle (θ); - producing (S43) an energy spectrum of an estimated elevation angle (θ) of the object for the range ( R ( t n )) at each of the successive measurement points in time (t n ), by combining a plurality of measurement vectors over a sliding range window (W); and - estimating (S44, S45) the height (h 2 ) of the object from the produced energy spectrum of the estimated elevation angle (θ); wherein, the length (ω) of the sliding range window (W) is variable and determined (S42) by estimating the range interval covered by a full phase cycle of a phase difference between the direct path and the indirect path, from a current value of the range (R) and a current estimate (h 2 ) of the height of the object . <EOS>