摘要 |
PROBLEM TO BE SOLVED: To consecutively maintain an accurate heading.SOLUTION: A method and system for compensating for significant soft iron magnetic disturbances in a heading reference system, such as an aircraft heading reference system, such as an integrated standby unit; or a vehicle inertial system, provides a heading correction signal to the heading reference system when a detected difference in value between a gyro compass heading relative to magnetic north and a magnetometer reading during a measurement period exceeds a predetermined acceptable threshold value of change, such as one based on the expected gyro compass drift over that period. Upon receipt of the heading correction signal, the gyro compass heading is adjusted to maintain an accurate heading relative to true magnetic north. If this threshold value is not exceeded, then the magnetometer reading is used for the heading value. This method is iteratively repeated to continually maintain an accurate heading and may be employed for each heading measurement axis. |