Method and computer-readable storage medium with instructions for processing data in an internal navigation system
First Claim
1. A method for processing data in an inertial navigation system having a Kalman filter, the method comprising:
- receiving data from an inertial measurement unit;
determining whether the inertial measurement unit is in a zero-velocity condition;
determining whether a predetermined number of data cycles have occurred with a zero-velocity condition present;
performing a zero-velocity update to the Kalman filter if the inertial measurement unit is in a zero-velocity condition;
performing a fixed-azimuth update to the Kalman filter if the predetermined number of data cycles have occurred with a zero-velocity condition present; and
outputting an estimate of the position of the inertial measurement unit.
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Abstract
A method for processing data in an inertial navigation system having a Kalman filter and computer-readable storage medium containing instructions to configure a processor to perform the same. The method produces more accurate estimates of the position, velocity and attitude of the inertial measurement unit. The method is fully automatic and enables zero-velocity updates and fixed-azimuth updates to be performed simultaneously. The method may also include a multi-stage filtering process to filter digital compass data when used in an environment with extraterrestrial magnetic field sources. The method may also include a fixed-lag smoother to improve estimates of the position, velocity and attitude of the inertial measurement unit. The method also may include processes to constrain altitude errors.
84 Citations
20 Claims
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1. A method for processing data in an inertial navigation system having a Kalman filter, the method comprising:
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receiving data from an inertial measurement unit; determining whether the inertial measurement unit is in a zero-velocity condition; determining whether a predetermined number of data cycles have occurred with a zero-velocity condition present; performing a zero-velocity update to the Kalman filter if the inertial measurement unit is in a zero-velocity condition; performing a fixed-azimuth update to the Kalman filter if the predetermined number of data cycles have occurred with a zero-velocity condition present; and outputting an estimate of the position of the inertial measurement unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A computer-readable storage medium containing instructions to configure a processor to perform a method for processing data in an inertial navigation system having a Kalman filter, the method comprising:
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receiving data from an inertial measurement unit; determining whether the inertial measurement unit is in a zero-velocity condition; performing a zero-velocity update to the Kalman filter if the inertial measurement unit is in a zero-velocity condition; determining whether a predetermined number of data cycles have occurred with a zero-velocity condition present; performing a fixed-azimuth update to the Kalman filter if a user-defined number of data cycles have occurred with a zero-velocity condition present; and outputting an estimate of the position of the inertial measurement unit. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification