Abstract: A method for detecting conflicts between aircraft flying in controlled airspace. The method determines whether pairs of aircraft flight routes violate a predetermined proximity test. The separation of pairs of aircraft whose flight routes do not violate the proximity test is assured. For pairs of aircraft whose flight routes violate the proximity test, the method calculates the parts of their flight routes that breach the separation threshold, the conflict paths (406, 408). The conflict paths are stored. The method determines the portions of aircraft trajectories corresponding to the conflict paths. The separation of aircraft that have flown past their conflict paths is assured. The separation time and separation altitude of pairs of aircraft that have not flown past their conflict paths are calculated. The separation time and separation altitude are used to determine future circumstances whereby the pairs of aircraft may lose separation.

Abstract: The invention discloses a signal decoding method for C3 decoding on a data storage medium. The data storage medium contains a lot of sectors, and each sector contains two C3 codes. Each C3 code contains a plurality of P codes and Q codes. The syndrome operation for an (N+1)th code and an error-correction for an N-th code are pipelined. An address for the (N+1)th code minus a predetermined value is an address for the N-th code.