A computer includes a processor and a memory storing instructions executable by the processor to collect at least one set of data with a first Doppler sensor, each set of data including a radial distance, an azimuth angle and a range rate between the first Doppler sensor and a target, collect at least one set of data with a second Doppler sensor, determine that the collected sets of data include a first, second, and third set, determine respective radial components of a ground velocity of the target based on the first, second and third sets of data a position on a host vehicle of the respective Doppler sensor that collected the sets of data, and determine a linear velocity of the target and a yaw rate of the target based on the radial components of the ground velocity of the target.