A method of determining the de-aliased range rate of a target in a horizontal plane by a host vehicle equipped with a radar system, said radar system including a radar sensor unit adapted to receive signals emitted from said host vehicle and reflected by said target, comprising: a) emitting a radar signal at a single time-point instance and determining from a plurality (m) of point radar detections measurements therefrom captured from said radar sensor unit, the values for each point detection of, azimuth and range rate; ( θ i, ṙ i), i = 1,....,m; b) for each point detection determining a range rate compensated value ( ṙ i, cmp) from the output of step a) and the vehicle or sensor unit speed from the following equation r ̇ i, cmp = r ̇ i + u s cos θ i + v s sin θ i where u s is the host vehicle or sensor longitudinal velocity and v s is the host vehicle or sensor lateral velocity; c) determining a plurality (j) of velocity profile hypotheses; d) for each (j-th) hypothesis determining modified compensated hypothesis range rates ( ṙ i, j, cmp) in respect of each point detection on the target, based on the values of range rate compensated ( ṙ i, cmp) determined from step b) from the following equation: r ̇ i, j, cmp = r ̇ i, cmp + j r ̇ ua where ṙ ua is the unambiguous interval of measured range rate; e) for each j-th hypothesis, determining values of the longitudinal and lateral components of the range rate equation of the target c t,j and s t,j from the results of step d) and a) where the range rate equation is: r ̇ i, j, cmp = cos θ i sin θ i c t, j s t, j f) for each j-th hypothesis and for each point detection determining a velocity profile estimator range rate r ̇ ^ i, j, cmp, calculated from the following equation: r ̇ ^ i, j, cmp = c ̃ t, j cosθ i + s ̃ t, j sinθ i where the values of θ i are determined from step a) and c̃ t,j and s̃ t,j the values of velocity profile components from step e) g) for each hypothesis, for one or more point detections, determining a measure of the dispersion of, or variation between the velocity profile estimator range rates r ̇ ^ i, j, cmp, for each velocity profile hypothesis from step f) and their respective modified range rates ( ṙ i, j, cmp) from step d), or the dispersion of, or variation between, one or both of the velocity profile components c̃ t,j and s̃ t,j for each velocity profile hypothesis, and selecting the velocity profile where said measure of dispersion or variation is the lowest; h) setting the de-aliased range rate as the velocity of the velocity hypothesis selected from step g). a) emitting a radar signal at a single time-point instance and determining from a plurality (m) of point radar detections measurements therefrom captured from said radar sensor unit, the values for each point detection of, azimuth and range rate; ( θ i, ṙ i), i = 1,....,m; b) for each point detection determining a range rate compensated value ( ṙ i, cmp) from the output of step a) and the vehicle or sensor unit speed from the following equation r ̇ i, cmp = r ̇ i + u s cos θ i + v s sin θ i where u s is the host vehicle or sensor longitudinal velocity and v s is the host vehicle or sensor lateral velocity; c) determining a plurality (j) of velocity profile hypotheses; d) for each (j-th) hypothesis determining modified compensated hypothesis range rates ( ṙ i, j, cmp) in respect of each point detection on the target, based on the values of range rate compensated ( ṙ i, cmp) determined from step b) from the following equation: r ̇ i, j, cmp = r ̇ i, cmp + j r ̇ ua where ṙ ua is the unambiguous interval of measured range rate; e) for each j-th hypothesis, determining values of the longitudinal and lateral components of the range rate equation of the target c t,j and s t,j from the results of step d) and a) where the range rate equation is: r ̇ i, j, cmp = cos θ i sin θ i c t, j s t, j f) for each j-th hypothesis and for each point detection determining a velocity profile estimator range rate r ̇ ^ i, j, cmp, calculated from the following equation: r ̇ ^ i, j, cmp = c ̃ t, j cosθ i + s ̃ t, j sinθ i where the values of θ i are determined from step a) and c̃ t,j and s̃ t,j the values of velocity profile components from step e) g) for each hypothesis, for one or more point detections, determining a measure of the dispersion of, or variation between the velocity profile estimator range rates r ̇ ^ i, j, cmp, for each velocity profile hypothesis from step f) and their respective modified range rates ( ṙ i, j, cmp) from step d), or the dispersion of, or variation between, one or both of the velocity profile components c̃ t,j and s̃ t,j for each velocity profile hypothesis, and selecting the velocity profile where said measure of dispersion or variation is the lowest; h) setting the de-aliased range rate as the velocity of the velocity hypothesis selected from step g).