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 between the detection device and the object varies over time: - producing 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; 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 is variable and determined 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 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 between the detection device and the object varies over time: - producing 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; and - estimating (S44, S45) the height (h 2) of the object from the produced energy spectrum of the estimated elevation angle (θ); - producing 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; 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 is variable and determined 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 and a current estimate (h 2) of the height of the object.