Patent ID: 9207079
Filing Date: 2015-12-08
Classification: G01C

Abstract:
1. A method for compensating for soft iron magnetic disturbances in a heading reference system, said system comprising a heading gyro disposed along a heading measurement axis and a magnetometer coupled to said heading gyro for providing an accurate heading relative to magnetic north; said method comprising the steps of: detecting changes in said magnetometer due to soft iron magnetic disturbances during a detection period for providing a first detected magnitude of change; detecting changes in said heading gyro relative to magnetic north during said detection period for providing a second detected magnitude of change; comparing said first and second detected magnitude of changes for providing a potential difference value of change; providing a predetermined acceptable threshold value of change based on a gyro drift; determining if said potential difference value of change exceeds said predetermined acceptable threshold value of change; and providing a heading correction value to said heading reference system when said potential difference value of change exceeds said predetermined acceptable threshold value of change for enabling adjustment of said heading gyro to maintain said accurate heading in the face of said soft iron magnetic disturbances.