A Method of Increasing the Precision of Measuring Altitude in the Prearranged Altitude Flight of the UAV

摘要

For carrying out various flight missions，some unmanned aerial vehicles need to fly over the ocean’s surface，especially near the offing, so they must to be equipped with high precision devices of keeping level altitude to complete such flight missions．The high precision device usually adopts a radio altimeter of less error in running to measure altitude and height change． Result from the influence of random jamming signals，for example wave clutter (the kind of wave is brought by the ocean wave and so on) and background noises and so on，radio altimeter’s operating error of measuring altitudes becomes relatively serious．Consequently the degree of accuracy of height-control loop goes down and which influences the flight of the UVA over the ocean’s surface． Therefore, for the sake of eliminating ill effects on the radio altimeter which such random jamming signals，including wave clutter and background noises and the like，bring about，some essential processing methods should be taken toward the output signal of the radio altimeter．This paper discusses a method based on Wiener filtering and optimal estimation which improves upon the anti-jamming ability of the radio altimeter．