Strapdown Inertial Navigation Heave Measurement Method Using Multiple Low-Pass Filter Units

    公开(公告)号:US20220326019A1

    公开(公告)日:2022-10-13

    申请号:US17846128

    申请日:2022-06-22

    Abstract: The disclosure discloses a strapdown inertial navigation heave measurement method using multiple low-pass filter units, including: firstly, collecting data of a gyroscope and an accelerometer by a system, obtaining attitude information of a carrier by using initial alignment, and then, obtaining a relationship matrix between a body coordinate system and a geographic coordinate system by using the attitude information; obtaining a relationship matrix between the geographic coordinate system and a semi-fixed coordinate system according to a geographic position, and obtaining a rough vertical acceleration by using a direction cosine matrix, output information of the accelerometer and gravity information; then, filtering out low-frequency signals by using a double-filter unit and one integral link to obtain a relatively accurate velocity signal; and furthermore, enabling the vertical acceleration to be subjected to a triple-filter unit and two integral links to obtain an accurate heave displacement. The method avoids the problem of phase lead caused by traditional addition of high-pass filters, and can provide a reference for ship swaying reduction operations, ship carrier lifts, ship-borne weapon launch and heave compensation of various offshore platforms.

    Self-adaptive horizontal attitude measurement method based on motion state monitoring

    公开(公告)号:US12061086B2

    公开(公告)日:2024-08-13

    申请号:US17844224

    申请日:2022-06-20

    CPC classification number: G01C21/188 G01C21/18

    Abstract: Disclosed is a self-adaptive horizontal attitude measurement method based on motion state monitoring. Based on a newly established state space model, a horizontal attitude angle is taken as a state variable, an angular velocity increment Δωb for compensating a random constant zero offset is taken as a control input of a system equation, and a specific force fb for compensating the random constant zero offset is taken as a measurement quantity. Meanwhile, judgment conditions for a maneuvering state of a carrier are improved, and maneuvering information of the carrier is judged by comprehensively utilizing acceleration information and angular velocity information output by a micro electro mechanical system inertial measurement unit (MEMS-IMU), whereby a measurement noise matrix of a filter can be automatically adjusted, thereby effectively reducing the influence of carrier maneuvering on the calculation of a horizontal attitude. The method has no special requirement on the maneuvering state of the carrier, and can ensure that the system has high attitude measurement precision in different motion states without an external information assistance.

    Strapdown inertial navigation heave measurement method using multiple low-pass filter units

    公开(公告)号:US12061087B2

    公开(公告)日:2024-08-13

    申请号:US17846128

    申请日:2022-06-22

    CPC classification number: G01C21/203 G01C21/16

    Abstract: A strapdown inertial navigation heave measurement method using multiple low-pass filter units includes: firstly, collecting data of a gyroscope and an accelerometer by a system, obtaining attitude information of a carrier by using initial alignment, and then, obtaining a relationship matrix between a body coordinate system and a geographic coordinate system by using the attitude information; obtaining a relationship matrix between the geographic coordinate system and a reference coordinate system according to a geographic position, and obtaining a rough vertical acceleration by using a direction cosine matrix, output information of the accelerometer and gravity information; then, filtering out low-frequency signals by using a first filter unit and integration to obtain a relatively accurate velocity signal; and furthermore, enabling the vertical acceleration to be subjected to a second filter unit and integration to obtain an accurate heave displacement.

    Self-Adaptive Horizontal Attitude Measurement Method based on Motion State Monitoring

    公开(公告)号:US20220326017A1

    公开(公告)日:2022-10-13

    申请号:US17844224

    申请日:2022-06-20

    Abstract: Disclosed is a self-adaptive horizontal attitude measurement method based on motion state monitoring. Based on a newly established state space model, a horizontal attitude angle is taken as a state variable, an angular velocity increment Δωb for compensating a random constant zero offset is taken as a control input of a system equation, and a specific force fb for compensating the random constant zero offset is taken as a measurement quantity. Meanwhile, judgment conditions for a maneuvering state of a carrier are improved, and maneuvering information of the carrier is judged by comprehensively utilizing acceleration information and angular velocity information output by a micro electro mechanical system inertial measurement unit (MEMS-IMU), whereby a measurement noise matrix of a filter can be automatically adjusted, thereby effectively reducing the influence of carrier maneuvering on the calculation of a horizontal attitude. The method has no special requirement on the maneuvering state of the carrier, and can ensure that the system has high attitude measurement precision in different motion states without an external information assistance.

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