Patent ID: 9037318
Filing Date: 2015-05-19
Classification: G01C,G05D

Abstract:
1. An inertial system, the system comprising: one or more inertial reference units (IRUs) each providing a heading information signal; an attitude heading reference system (AHRS) receiving the heading information signal from each of the one or more IRUs, the AHRS including at least one set of gyroscopes and accelerometers, a memory device and a heading calculator; wherein the heading calculator is configured to receive a slaving signal that is generated based on the heading information signal from at least one of the one or more IRUs, the heading calculator further configured to receive a signal from the at least one set of gyroscopes and accelerometers; a voter module for generating the slaving signal, wherein the voter module determines a reliability of heading information provided from the one or more IRUs based on relative agreement of heading information between at least two IRUs; wherein, when the reliable heading information is being received from at least one of the one or more IRUs, the AHRS operates in a normal mode where the heading calculator generates a heading output signal from the slaving signal; and wherein, when reliable heading information is not received from at least one of the one or more IRUs, the AHRS switches to a directional-gyro (DG) mode of operation where the heading calculator generates the heading output signal from an output of the at least one set of gyroscopes and accelerometers and information stored in the memory device regarding previously reliable heading information.