Range safety communication system and method utilizing pseudorandom

Abstract

A system and method for transmitting one or more range safety commands to a launch vehicle which includes transmitting structure having a pilot code generator and at least one additional code generator for generating at least one transmitter command code corresponding to a range safety command. A PN clock continuously locks the one or more transmitter command codes with the transmitter pilot code. Sequence selection structure selectively applies the one or more transmitter command codes to a modulator which combines the transmitter pilot code and the applied transmitter command codes with a carrier signal, and transmits the pilot and command codes through a relay satellite to the vehicle. Receiving structure in the vehicle recovers the pilot and command codes, and aligns a locally generated pilot code with the recovered pilot code. At least one local command code generator, which is synchronized to the local pilot code, is included in the receiving structure for generating one or more local command codes which correspond to the transmitter command codes. The local command codes and recovered transmitter command codes are sampled, and the samples compared over an acquisition period. If at the end of an acquisition period any set of samples exceeds a predetermined level of correspondence, then a hit detect signal is transmitted to decision logic in the vehicle. If all of the hit detect signals for a command are detected by the decision logic within a predetermined time interval, then the decision logic activates the command.