Abstract: A three-dimensional object detection system includes a transmission device configured so as to transmit signals using a colored transmission method in a first plane, a reception device comprising at least two sensors arranged in a second plane perpendicular to the first plane, and processing means for processing the transmitted and received signals, wherein the reception device is raised with respect to the transmission device, and wherein the processing means are configured so as to detect the presence of objects: in the first plane based on the signals received from at least one of the sensors using the color of the transmitted signal, in the second plane based on the signals received from at least two of the sensors. The method for determining the presence of objects and for estimating their associated direction and distance is also provided.

Abstract: The present invention relates to the field of protecting geographic areas against undesirable, even hostile, intrusions from threatening moving objects. The subject of the invention is a bistatic radiofrequency detection barrier having means for transmitting one or more waves through a directional antenna and means for receiving signals through a directional antenna pointing in the transmission direction. This antenna includes auxiliary means for transmitting a wave through a non-directional antenna and means for comparing the relative levels of the echos received from the wave transmitted by the main, directional transmission channel, and the echos originating from the wave transmitted by the auxiliary transmission channel. The result of the comparison makes it possible to identify the echos deriving from a wave transmitted in the direction of the side lobes of the directional transmission antenna, and so reduce the number of false intrusion alarms.