Systems and methods for providing aircraft heading information are provided. In one embodiment, an attitude heading reference device comprises: at least one interface for receiving heading information from one or more IRUs; at least one set of gyroscopes and accelerometers; a memory device for storing data representing heading information received via the at least one interface; and a heading calculator coupled to the at least one interface, the at least one set of gyroscopes and accelerometers, and the memory device. The heading calculator generating a heading output signal based on heading information when reliable heading information is received over the at least one interface; the heading calculator generating the heading output signal based on data from the memory device regarding previously reliable heading information and an output of the at least one set of gyroscopes and accelerometers when reliable heading information is not received over the at least one interface.