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US 10,907,936 B2Granted
State estimation
AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorsPaul D. Zemany, Matthew F. Chrobak, Egor V. Degtiarev
Life of this patent
Estimating the term…
Abstract
A system and method for state estimation in spinning projectiles is provided. The state estimation is based, at least in part, on magnetic sensor data, angular velocity data, and correction terms applied to the magnetic sensor data and the angular velocity data. The system and method for state estimation in spinning projectiles estimates roll angles and roll rates of the spinning projectiles. The roll angle and roll rate estimates allow steering commands to be applied to steer the spinning projectiles in the proper direction.
Claims20
A method comprising:
- providing known geomagnetic field vectors to a spinning projectile;
- firing the spinning projectile from a launch assembly towards a target;
- estimating a sensor offset of at least one magnetic sensor;
- estimating a first distortion caused by a first source of distortion;
- wherein the first source of distortion is a permanent magnetic field of the spinning projectile;
- estimating at least one second distortion caused by at least one second source of distortion;
- estimating, with the at least magnetic sensor, a magnetic data output associated with a local magnetic field relative to the spinning projectile;
- removing the estimated sensor offset, the estimated first distortion, and the estimated at least one second distortion from the magnetic data output associated with the local magnetic field to provide a corrected magnetic data output associated with the local magnetic field;
- determining corrected geomagnetic field vectors of the spinning projectile based, at least in part, on the known geomagnetic field vectors and the corrected magnetic data output associated with the local magnetic field;
- determining an elevation of the spinning projectile;
- determining an azimuth of the spinning projectile;
- estimating a roll angle of the spinning projectile based, at least in part, on the corrected geomagnetic field vectors of the spinning projectile, the elevation of the spinning projectile, and the azimuth of the spinning projectile;
- estimating, with at least one angular rate sensor, a roll rate of the spinning projectile;
- integrating the estimated roll rate;
- merging the estimated roll angle with the integrated estimated roll rate to provide an updated estimated roll angle of the spinning projectile and an estimated bias of the at least one angular rate sensor;
- and
- removing the bias of the at least one angular rate sensor to provide an updated estimated roll rate of the spinning projectile.
14 more elements
A state estimation system for a spinning projectile, comprising:
- at least one processor that receives known geomagnetic field vectors;
- at least one magnetic sensor that estimates a magnetic data output associated with a local magnetic field relative to the spinning projectile;
- a first source of distortion providing a first distortion;
- wherein the first source of distortion is a permanent magnetic field of the spinning projectile;
- first estimation logic that estimates a sensor offset of the at least one magnetic sensor;
- second estimation logic that estimates the first distortion;
- at least one second distortion source providing at least one second distortion;
- third estimation logic that estimates the second distortion;
- first correction logic that removes the estimated sensor offset, the estimated first distortion, and the estimated at least one second distortion from the magnetic data output associated with the local magnetic field to provide a corrected magnetic data output associated with the local magnetic field;
- and
- geomagnetic logic that determines corrected geomagnetic field vectors of the spinning projectile based, at least in part, on the known geomagnetic field vectors and the corrected magnetic data output associated with the local magnetic field;
- elevation logic that determines an elevation of the spinning projectile;
- azimuth logic that determines an azimuth of the spinning projectile;
- roll angle estimation logic that estimates a roll angle of the spinning projectile based, at least in part, on the corrected geomagnetic field vectors of the spinning projectile, the elevation of the spinning projectile, and the azimuth of the spinning projectile;
- at least one angular rate sensor that estimates a roll rate of the spinning projectile;
- integration logic that integrates the estimated roll rate;
- merging logic that merges the estimated roll angle with the integrated estimated roll rate to provide an updated estimated roll angle of the spinning projectile and an estimated bias of the at least one angular rate sensor;
- and
- second correction logic that removes the bias of the at least one angular rate sensor to provide an updated estimated roll rate of the spinning projectile.
16 more elements
Dependencies are inferred from the claim text.