Navigation integrity in GPS challenged environments

    公开(公告)号:US11879736B2

    公开(公告)日:2024-01-23

    申请号:US17018846

    申请日:2020-09-11

    CPC classification number: G01C21/005

    Abstract: 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.

    BIAS FIELD CONTROL OF TOTAL-FIELD OPTICALLY PUMPED MAGNETOMETERS (OPMs) FOR IMPROVED DETECTION

    公开(公告)号:US20230333178A1

    公开(公告)日:2023-10-19

    申请号:US17722017

    申请日:2022-04-15

    CPC classification number: G01R33/26 G01R33/032

    Abstract: 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.

    NAVIGATION INTEGRITY IN GPS CHALLENGED ENVIRONMENTS

    公开(公告)号:US20230392929A1

    公开(公告)日:2023-12-07

    申请号:US17018846

    申请日:2020-09-11

    CPC classification number: G05D1/0088 G05D1/0077 G05D1/101

    Abstract: 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.

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

    公开(公告)号:US11965943B2

    公开(公告)日:2024-04-23

    申请号:US17722017

    申请日:2022-04-15

    CPC classification number: G01R33/26 G01R33/032

    Abstract: 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.

    IMAGE GEO-REGISTRATION FOR ABSOLUTE NAVIGATION AIDING USING UNCERTAINY INFORMATION FROM THE ON-BOARD NAVIGATION SYSTEM

    公开(公告)号:US20190242711A1

    公开(公告)日:2019-08-08

    申请号:US15891806

    申请日:2018-02-08

    Abstract: 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.

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