TARGET ALTITUDE ESTIMATION BASED ON MEASUREMENTS OBTAINED BY MEANS OF A PASSIVE RADAR

The present invention relates to a method for estimating the altitude of a target. Said method comprises: acquiring first quantities indicative of bistatic range measurements associated with a target and carried out on the basis of radio frequency signals received by a passive radar sensor and transmitted by at least three transmitters of opportunity, each of which transmits using a respective carrier frequency different from the carrier frequencies used by the other transmitters of opportunity; acquiring second quantities indicative of bistatic range rate measurements associated with the target and carried out on the basis of said radio frequency signals received by the passive radar sensor and transmitted by the at least three transmitters of opportunity; and estimating a two-dimensional kinematic state of the target on the basis of the first and the second quantities, said two- dimensional kinematic state comprising a two-dimensional position of the target defined by two coordinates expressed in a polar reference system in terms of range and azimuth, or in a corresponding Cartesian reference system, and a two- dimensional velocity of the target defined by two components expressed in the polar reference system in terms of range and azimuth, or in the corresponding Cartesian reference system. The method is characterized by further comprising estimating the altitude of the target and the elevation component of the velocity of the target on the basis of the two-dimensional kinematic state of the target and the first and the second quantities so as to minimize a functional related to at least the second quantities.