Method for assisting in the landing or decking of a manned aircraft, the aircraft being of the engine-powered light aircraft type suitable for visual flight, the method being implemented by a system comprising a device on the ground for locating the aircraft, the aircraft having an onboard sender sending signals asynchronously to the device on the ground, the method comprising at least the following steps: - the locating device on the ground determines, based on signals sent by said sender, the position and/or the movement of the aircraft, the locating device on the ground comprising a reference beacon and at least two passive sensors (211, 212) which are spaced apart, each of the at least two passive sensors (211, 212) comprising an antenna panel comprising a plurality of antenna blocks on its surface, the at least two passive sensors (211, 212) being fixed at one end of a landing or decking surface in a plane that is substantially orthogonal with respect to said landing or decking surface so as to radiate toward it, each sensor (211, 212) being inclined about an axis that is orthogonal with respect to the plane of said sensor, such that the pairs of antenna blocks of said sensor are arranged along an axis forming an angle α with an axis that is orthogonal with respect to said landing or decking surface, said sensors being capable of receiving said signals sent by said sender in order to locate said aircraft via triangulation, said reference beacon being placed at the other end of said landing or decking surface and sending a calibration signal to said sensors at a frequency that differs from the frequency of the signals sent by said sender; - said locating device on the ground transmits the previously determined aircraft position and/or movement data to the aircraft; - display means in the aircraft or radio communication means in the aircraft (160, 160', 170) show the pilot of the aircraft at least some of said data to assist in the landing or decking. - the locating device on the ground determines, based on signals sent by said sender, the position and/or the movement of the aircraft, the locating device on the ground comprising a reference beacon and at least two passive sensors (211, 212) which are spaced apart, each of the at least two passive sensors (211, 212) comprising an antenna panel comprising a plurality of antenna blocks on its surface, the at least two passive sensors (211, 212) being fixed at one end of a landing or decking surface in a plane that is substantially orthogonal with respect to said landing or decking surface so as to radiate toward it, each sensor (211, 212) being inclined about an axis that is orthogonal with respect to the plane of said sensor, such that the pairs of antenna blocks of said sensor are arranged along an axis forming an angle α with an axis that is orthogonal with respect to said landing or decking surface, said sensors being capable of receiving said signals sent by said sender in order to locate said aircraft via triangulation, said reference beacon being placed at the other end of said landing or decking surface and sending a calibration signal to said sensors at a frequency that differs from the frequency of the signals sent by said sender; - said locating device on the ground transmits the previously determined aircraft position and/or movement data to the aircraft; - display means in the aircraft or radio communication means in the aircraft (160, 160', 170) show the pilot of the aircraft at least some of said data to assist in the landing or decking.