A corner sensor for a motor vehicle capable of communicating over a wireless communication link with an authentication device and including: an array of antennae; and an electronic control unit configured to: determine the phase difference between the segments received by the antennae; determine the probability of each angle of incidence over a range of angles that is predetermined on the basis of the determined phase differences and of a predefined table, so as to determine a probability profile; measure the power of the segments received by the antennae of the array of antennae so as to determine a power profile; determine the actual angle of incidence of the signal by multiplying the probability profile with the power profile; and send the value of the determined actual angle of incidence to a central electronic control unit of the vehicle.