The present invention relates to system for detecting obstacles (13, 55, 56, 57) on the ground (15) onboard a carrier (1). The detection system comprises at least two continuous-wave radars (2, 3, 4). The radars (2, 3, 4) are linked to a system (15) for utilizing the detection data arising from the radars (2, 3, 4). The detection system performs localization of an obstacle (13, 55, 56, 57): along a radial axis (12) between a radar (2, 3, 4) and the obstacle (13, 55, 56, 57), by calculating the distance between the radar (2, 3, 4) and the obstacle (13, 55, 56, 57); along a vertical axis (14) with respect to a radar (2, 3, 4), by calculating the elevation of the obstacle (13, 55, 56, 57) using monopulse deviation-measurement processing. The detection system performs localization of an obstacles along a horizontal axis (18) transverse with respect to a sighting axis (11) of a radar (2, 3, 4), by calculating the azimuthal position of the obstacle (13, 55, 56, 57). The invention applies notably in respect of the detection of obstacles on the ground so as to avoid any collision between a taxiing aircraft and these obstacles.