Raytheon Company

James Thomas Landon

Kenneth L Moore

Jarrett M Perry

James K Ingersoll

Michael Vaujin

Thomas Lee Caylor

George Jeffrey Geier

Benjamin J Graham

Taehwan Kim

Richard B Choroszucha

George G Descamps

A controllable bias field Bbias is applied to a single total-field OPM to maintain signal lock when an observable magnetic field Bmeas enters the OPM's dead zone. One or more electromagnetic (EM) coils are placed in proximity to the single OPM. Based on either a calibration of the field or a measured signal strength, a current command is calculated and applied to the one or more coils to produce the bias field Bbias to lift the observable magnetic field Bmeas out of the dead zone. The bias level is updated at a rate sufficient to maintain signal lock without interfering with the operation of the OPM. This allows a single OPM to sense the observable magnetic field Bmeas in all directions without having to either re-orient the OPM or to use multiple orthogonally positioned OPMs.

Bias field control of total-field optically pumped magnetometers (OPMs) for improved detection

Systems and methods for detecting degraded navigation sensors are based on a policy derived from a Partially Observable Markoff Decision Process (POMDP). Navigation parameters derived from the navigation sensors are provided to individual Kalman filters. A covariance of each of the filters is indicative of a probability of degradation of a sensor from which the navigation parameter is derived. Outputs of the Kalman filters are provided to a master filter. The master filter is compared to a criterion to determine whether there are indicia of a degraded sensor. If such an indicia are present, the Policy is consulted to determine which of the sensors are degraded. Consideration of degraded sensors when navigating a vehicle is inhibited.

Navigation integrity in GPS challenged environments

A system and method for feeding back and incorporating the uncertainty distribution of the state estimate output by the INS in the image geo-registration process to handle larger navigation errors, provide a full six degree of freedom position and attitude absolute navigation update for the navigation system and provide a more accurate update for autonomous aerial, underwater or ground vehicles. Generating the update simultaneously for multiple images may provide a more robust solution to address any observability issues that may be present, the ability to fuse different sensor modalities and in general more accurate updates. Key frames may be used to improve the computational efficiency of the method.

Image geo-registration for absolute navigation aiding using uncertainy information from the on-board navigation system

AROTAN provides for autonomous terrain aided navigation that is fully independent of the position uncertainty of the vehicle during flight. AROTAN aligns a grid to the search space and periodically updates the search space during the measurement history to account for growth in position uncertainty. AROTAN computes terrain sufficiency statistics for a moving history to provide robust criteria for when to perform the correlation. A post-correlation refinement provides an additional correction of the horizontal position error and a correction of the altitude. AROTAN can quickly provide the vehicle's location based on the correlation from a single measurement history.

Autonomous range-only terrain aided navigation

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Oro Valley, AZ, United States of America

James Thomas Landon