Gyro aided magnetic compass
First Claim
1. A device comprising:
- a geomagnetic sensor for sensing a heading and providing a corresponding first heading signal;
an angular velocity sensor for sensing motion and outputting a corresponding angular velocity signal;
a signal integrator communicatively coupled to the angular velocity sensor to receive the angular velocity signal and output a second heading signal; and
a processing unit communicatively coupled to the geomagnetic sensor and signal integrator, the processing unit configured to receive an initial reference heading from the geomagnetic sensor, generate a hybrid heading signal based on the initial reference heading and the second heading signal, and blend the first heading signal with the hybrid heading signal at an adaptive time interval, wherein said adaptive time interval varies based upon the presence of magnetic compass errors as determined by said processing unit.
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Accused Products
Abstract
An improved method, system, and device for a compass combining an electronic magnetic compass and an angular velocity sensing gyroscope. One aspect of the invention integrates an angular velocity output signal from an angular velocity sensor or rate gyroscope to determine the angle of motion. An initial magnetic heading is obtained from a geomagnetic sensor and used as a reference for the integrated angular velocity signal. A geomagnetic heading signal is blended with the angular velocity output signal at an adaptive time interval. The adaptive time interval is increased if the reliability of the magnetic field improves and decreased if the reliability of the magnetic field degenerates. Additionally, dynamic calibration of the angular velocity sensor may be performed to correct for gyroscope bias (zero offset), and/or gyroscope scale factor or gain.
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Citations
20 Claims
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1. A device comprising:
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a geomagnetic sensor for sensing a heading and providing a corresponding first heading signal;
an angular velocity sensor for sensing motion and outputting a corresponding angular velocity signal;
a signal integrator communicatively coupled to the angular velocity sensor to receive the angular velocity signal and output a second heading signal; and
a processing unit communicatively coupled to the geomagnetic sensor and signal integrator, the processing unit configured to receive an initial reference heading from the geomagnetic sensor, generate a hybrid heading signal based on the initial reference heading and the second heading signal, and blend the first heading signal with the hybrid heading signal at an adaptive time interval, wherein said adaptive time interval varies based upon the presence of magnetic compass errors as determined by said processing unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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sensing a heading of a body based on earth'"'"'s magnetic field;
providing an initial heading based on the sensed heading;
sensing angular motion of the body with an angular rate sensor;
providing an angular rate signal based on the sensed angular motion;
integrating the angular rate signal to provide a second heading signal;
generating a hybrid heading signal based on the initial heading and the second heading signal;
providing a first heading signal based on the sensed heading; and
blending in the first heading signal with the hybrid heading signal at an adaptive time interval, wherein said adaptive time interval varies based upon the presence of magnetic compass errors as determined by a processing unit. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A gyroscope-aided compass comprising:
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geomagnetic sensing means for sensing a heading and providing a corresponding first heading signal;
angular velocity sensing means for sensing motion and outputting a corresponding angular velocity signal;
signal integrating means communicatively coupled to the angular velocity sensing means to receive the angular velocity signal and output a second heading signal; and
a processing means communicatively coupled to the geomagnetic sensing means and signal integrating means, the processing means configured to receive an initial reference heading from the geomagnetic sensing means, generate a hybrid heading signal based on the initial reference heading and the second heading signal, and blend the first heading signal with the hybrid heading signal at an adaptive time interval, wherein said adaptive time interval varies based upon the presence of magnetic compass errors as determined by said processing means. - View Dependent Claims (18, 19, 20)
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Specification