Abstract: A detector system for a roll-stabilized aircraft includes a hollow rotatable toroidal ring within which a suitable sensor such as a TV sensor is fixed. The sensor observes the exterior of the aircraft through an observation window in the outer peripheral wall of the ring, which can be rotated about the roll axis of the aircraft. The apparatus includes appropriate instrumentation for determining the position relative to the aircraft of an object detected by the sensor.

Abstract: An airborne system is disclosed for determining the position of an aerial vehicle. According to the invention, a first memory is provided containing the general characteristics of different types of discrete landmarks and a second memory containing the geographic position of such landmarks on the ground to be flown over, a device for extracting, from the signals delivered by sensitive means, the general characteristics of said different types of discrete landmarks located on the ground being flown over, and a device for computing from the signals delivered by said sensitive means the relative positions of said vehicle with respect to said recognized landmarks, which it feeds to Kalman filter means.