Abstract: The invention comprises of a UAV designed to limit visually contrast and audibility in flight for covert surveillance operations, a method of configuring the UAVs structure to further reduce its visual signature to take account for the atmospheric and terrestrial environment it will operate in and a method of conducting a covert surveillance operation to actively minimise the UAVs visual & auditory signature from the viewpoint of an individual under surveillance. Both passive and active illumination are used to reduce the visual signature of the UAV. The UAV is actively camouflaged using lighting techniques that utilises the limitations of the human visual system and the optical effects of light interacting with the terrain, atmosphere and aircraft. The visual camouflage is directional. The audible signature of the UAV is reduced through the design of the propulsion system and the mode in which the UAV is operated.

Abstract: The invention comprises of a UAV designed to limit visually contrast and audibility in flight for covert surveillance operations, a method of configuring the UAVs structure to further reduce its visual signature to take account for the atmospheric and terrestrial environment it will operate in and a method of conducting a covert surveillance operation to actively minimise the UAVs visual & auditory signature from the viewpoint of an individual under surveillance. Both passive and active illumination are used to reduce the visual signature of the UAV. The UAV is actively camouflaged using lighting techniques that utilises the limitations of the human visual system and the optical effects of light interacting with the terrain, atmosphere and aircraft. The visual camouflage is directional. The audible signature of the UAV is reduced through the design of the propulsion system and the mode in which the UAV is operated.

Abstract: The invention is a self-contained, anti-collision safety system controller for high altitude, solar powered, unmanned aircraft. The controller acts as a backup to the primary safety system on the aircraft. It automatically turns on safety system equipment, such as a Mode S transponder and anti-collision lights when the aircraft descends below a pre-set pressure altitude. The pre-set altitude is chosen so that exceeds the altitude where other aircraft are operating and where collisions might occur. The controller measures the external air pressure to determine the aircrafts pressure altitude and activates/deactivates an internal switch between the power supply and the safety system equipment depending on whether the measured altitude exceeds the pre-set altitude level or not. The controller can be integrated into the exterior surface of an aircraft or internally within the airframe.

Abstract: The present invention provides a pod (100) for an aircraft (1000), comprising: a housing (1); a unit (2) comprising a propulsion system, the unit comprising at least one attachment point (5) for coupling the unit to the housing (1), wherein the position of the unit relative to the housing is selected from a plurality of positions based on the centre of gravity of the aircraft, such that deflection of control surfaces required for the aircraft to maintain a constant angle of attack is minimised. The invention also provides an aircraft (1000) having the pod (100) and a method of balancing the aircraft (1000).