公开(公告)号：US11512976B2

公开(公告)日：2022-11-29

申请号：US17236237

申请日：2021-04-21

Applicant: Harbin Institute of Technology

Inventor： Ya Zhang ,  Qian Sun ,  Wei Gao ,  Fei Yu ,  Yanyan Wang ,  Xiuwei Xia ,  Jianxiong Wei ,  Weiqi Miao

IPC: G01C25/00 ,  G01C21/18 ,  G06F17/16

Abstract: The disclosure discloses a latitude-free initial alignment method under a swaying base based on gradient descent optimization. Firstly, swaying base latitude-free alignment is regarded as a Wahba attitude determination problem to inhibit device noise interference, and an objective function is established based on a gravitational acceleration vector under an earth system; then an exact solution of the objective function is obtained through a gradient descent optimization method, and inertial system conversion quaternion estimation is achieved under the latitude-free condition; and finally, an attitude quaternion is determined by only using information of an accelerometer and a gyroscope of a strapdown attitude heading reference system, and therefore latitude-free initial alignment under the swaying base is achieved. The disclosure can solve the problem that initial alignment cannot be accomplished with unknown latitude under the swaying base, and thus the application range of the strapdown attitude heading reference system is ensured.

公开(公告)号：US20210262828A1

公开(公告)日：2021-08-26

申请号：US17236237

申请日：2021-04-21

Applicant: Harbin Institute of Technology

Inventor： Ya Zhang ,  Qian Sun ,  Wei Gao ,  Fei Yu ,  Yanyan Wang ,  Xiuwei Xia ,  Jianxiong Wei ,  Weiqi Miao

IPC: G01C25/00 ,  G01C21/18 ,  G06F17/16

Abstract: The disclosure discloses a latitude-free initial alignment method under a swaying base based on gradient descent optimization. Firstly, swaying base latitude-free alignment is regarded as a Wahba attitude determination problem to inhibit device noise interference, and an objective function is established based on a gravitational acceleration vector under an earth system; then an exact solution of the objective function is obtained through a gradient descent optimization method, and inertial system conversion quaternion estimation is achieved under the latitude-free condition; and finally, an attitude quaternion is determined by only using information of an accelerometer and a gyroscope of a strapdown attitude heading reference system, and therefore latitude-free initial alignment under the swaying base is achieved. The disclosure can solve the problem that initial alignment cannot be accomplished with unknown latitude under the swaying base, and thus the application range of the strapdown attitude heading reference system is ensured.

公开(公告)号：US20220136833A1

公开(公告)日：2022-05-05

申请号：US17236254

申请日：2021-04-21

Applicant: Harbin Institute of Technology

Inventor： Guochen Wang ,  Ya Zhang ,  Zicheng Wang ,  Hongze Gao ,  Yanyan Wang ,  Chao Liu ,  Jianbo Shao ,  Jingchun Li

IPC: G01C21/16

Abstract: The present disclosure discloses a latitude-free construction method for a gravity acceleration vector under a swaying base earth system. Firstly, a target function based on output information of an accelerator in a fixed-length sliding window under a swaying base is constructed; secondly, measurement information in a period of time window is used to construct the target function, and gradient descent optimization is used to obtain a rough value of qiib0; and finally, the rough value of qiib0 and an apparent motion of a gravity acceleration vector of an inertial system are used to construct the gravity acceleration vector under the earth coordinate system. The present disclosure makes a key breakthrough for solving the problem of high precision alignment of a ship with unknown latitude under a swaying base.