Patent ID: 8560180

Claim:
A velocity determination apparatus for determining a relative velocity between a first object, to which the velocity determination apparatus is attachable, and a second object, wherein the velocity determination apparatus comprises: a laser having a laser cavity for emitting first radiation for being reflected by the second object for generating reflected radiation being second radiation, wherein the first radiation and at least a part of the second radiation interfere within the laser cavity, an interference signal detector for detecting an interference signal, which depends on the interference within the laser cavity, a velocity determination unit for determining the relative velocity based on the interference signal, a reliability value determination unit for determining a reliability value for indicating the reliability of the determined relative velocity, wherein the reliability value determination unit is adapted to determine the reliability value based at least in part on the detected interference signal, wherein the first object is a vehicle and wherein the velocity determination apparatus further comprises a vehicle safety system for controlling a safety unit of the vehicle depending on the determined relative velocity and the determined reliability value.