Method and system for compensating for soft iron magnetic disturbances in multiple heading reference systems
First Claim
1. A system for compensating for soft iron magnetic disturbances in a heading reference system of a vehicle, the system comprising:
- a first magnetometer;
a second magnetometer located at a different location on the vehicle from the first magnetometer;
a first heading gyro coupled to the first magnetometer;
a second heading gyro coupled to the second magnetometer; and
a processor configured to;
receive magnetometer data from the first magnetometer;
receive magnetometer data from the second magnetometer;
determine whether one of the first or second magnetometers is potentially soft iron disturbed using the magnetometer data received from the first and second magnetometers and a magnetometer error threshold; and
in response to determining that one of the first or second magnetometers is potentially soft iron disturbed, determine which of the first or second magnetometers is potentially soft iron disturbed using the first and second heading gyros, a first threshold based on an expected drift of the first heading gyro, and a second threshold based on an expected drift of the second heading gyro.
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Accused Products
Abstract
A method and system for compensating for soft iron magnetic disturbances in multiple heading reference systems, such as aircraft heading reference systems, integrated standby units; or vehicle inertial systems, detects and provides a heading correction signal to the error prone heading reference system when a detected difference in value between a gyro heading relative to magnetic north and a magnetometer reading during a defined measurement period exceeds a predetermined acceptable threshold value of change, such as one based on the expected gyro drift over that period. Upon receipt of the heading correction signal, the gyro 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 periodically repeated in order to continually maintain an accurate heading and may be employed for each heading measurement axis.
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Citations
20 Claims
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1. A system for compensating for soft iron magnetic disturbances in a heading reference system of a vehicle, the system comprising:
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a first magnetometer; a second magnetometer located at a different location on the vehicle from the first magnetometer; a first heading gyro coupled to the first magnetometer; a second heading gyro coupled to the second magnetometer; and a processor configured to; receive magnetometer data from the first magnetometer; receive magnetometer data from the second magnetometer; determine whether one of the first or second magnetometers is potentially soft iron disturbed using the magnetometer data received from the first and second magnetometers and a magnetometer error threshold; and in response to determining that one of the first or second magnetometers is potentially soft iron disturbed, determine which of the first or second magnetometers is potentially soft iron disturbed using the first and second heading gyros, a first threshold based on an expected drift of the first heading gyro, and a second threshold based on an expected drift of the second heading gyro. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for compensating for soft iron magnetic disturbances in a heading reference system of a vehicle, the method comprising:
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receiving magnetometer data from a first magnetometer; receiving magnetometer data from a second magnetometer, wherein the second magnetometer is at a different location on the vehicle from the first magnetometer; determining whether one of the first or second magnetometers is potentially soft iron disturbed using the magnetometer data received from the first and second magnetometers and a magnetometer error threshold; and in response to determining that one of the first or second magnetometers is potentially soft iron disturbed, determining which of the first or second magnetometers is potentially soft iron disturbed by using;
a first heading gyro associated with the first magnetometer and a second heading gyro associated with the second magnetometer, a first threshold based on an expected drift of the first heading gyro, and a second threshold based on an expected drift of the second heading gyro. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification