A vehicle radar system where, for each one of a plurality of radar cycles, the radar system is arranged to provide a measured azimuth angle (θ m) and a measured radial velocity (v dm) for a first plurality of detections (9, 20), and where, for each one of said plurality of radar cycles, the radar system is arranged to: - select one detection from said first plurality of detections (9, 20) for each one of two velocity components (v x, v y) comprised in a set of components (v x, v y, a x, a y; a) to be determined, where the two velocity components (v x, v y) define a full velocity vector for a relative velocity (v r); characterized in that the radar system is further arranged to: - select one detection from a second plurality of detections (9, 20) for each one of at least one corresponding acceleration component (a x, a y; a); - calculate said components (v x, v y, a x, a y; a) for the selected detections; - determine a calculated radial velocity (v dc) for each one of at least a part of the other detections in said first plurality of detections (9, 20) by means of said calculated components (v x, v y, a x, a y; a); - determine an error between each calculated radial velocity (v dc) and the measured radial velocity (v dm); - determine the number of inliers, where an inlier corresponds to an error that falls below an inlier threshold; where the radar system furthermore is arranged to choose the set of components (v x, v y, a x, a y; a) that results in the largest number of inliers and where the radar system is arranged to calculate said components (v x, v y, a x, a y; a) by solving for these from the expression V dm = V x + a x Δ t cos θ m + V y + a y Δ t sin θ m for each selected detection, where θ m constitutes a measured angle between a radar system reference line and a direction towards the detection in question. - select one detection from said first plurality of detections (9, 20) for each one of two velocity components (v x, v y) comprised in a set of components (v x, v y, a x, a y; a) to be determined, where the two velocity components (v x, v y) define a full velocity vector for a relative velocity (v r); characterized in that the radar system is further arranged to: - select one detection from a second plurality of detections (9, 20) for each one of at least one corresponding acceleration component (a x, a y; a); - calculate said components (v x, v y, a x, a y; a) for the selected detections; - determine a calculated radial velocity (v dc) for each one of at least a part of the other detections in said first plurality of detections (9, 20) by means of said calculated components (v x, v y, a x, a y; a); - determine an error between each calculated radial velocity (v dc) and the measured radial velocity (v dm); - determine the number of inliers, where an inlier corresponds to an error that falls below an inlier threshold; where the radar system furthermore is arranged to choose the set of components (v x, v y, a x, a y; a) that results in the largest number of inliers and where the radar system is arranged to calculate said components (v x, v y, a x, a y; a) by solving for these from the expression V dm = V x + a x Δ t cos θ m + V y + a y Δ t sin θ m for each selected detection, where θ m constitutes a measured angle between a radar system reference line and a direction towards the detection in question. - select one detection from a second plurality of detections (9, 20) for each one of at least one corresponding acceleration component (a x, a y; a); - calculate said components (v x, v y, a x, a y; a) for the selected detections; - determine a calculated radial velocity (v dc) for each one of at least a part of the other detections in said first plurality of detections (9, 20) by means of said calculated components (v x, v y, a x, a y; a); - determine an error between each calculated radial velocity (v dc) and the measured radial velocity (v dm); - determine the number of inliers, where an inlier corresponds to an error that falls below an inlier threshold;