A PRELIMINARY STUDY OF PREDICTION TECHNIQUES FOR AIRCRAFT CARRIER MOTIONS AT SEA

Abstract : Mathematical techniques for calculating ship motion time histories are developed for application to the aircraft carrier landing operation. Various methods for short-term prediction of motion time history are considered, based on both deterministic and statistical techniques. The most attractive approach for prediction purposes is the deterministic technique based on a convolution integral representation, with wave height measurements at the bow serving as the input data. A kernel-type weighting function, which operates on the input to provide the predicted motion history, is derived from ship response functions, and is shown to yield good pitch prediction up to 6 seconds ahead. The limitations of classical statistical prediction techniques, as well as practical implementation difficulties, are exhibited. Certain aspects of recent prediction theory developments are considered for a proposed hybrid prediction technique (i.e. containing elements of both deterministic and statistical approaches) that will be compatible with the envisioned digital format of the predictor, and which will increase the prediction time.