Contour line matching method based on sliding window data backtracking

Patent metadata

Field	Value
Publication number	US-11835344-B2
Application number	US-202218253858-A
Country	US
Kind code	B2
Filing date	Oct 10, 2022
Priority date	Nov 18, 2021
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

To obtain a global optimal navigation track, a contour line matching method based on sliding window data backtracking includes the steps of determining sliding window parameters according to the calculation performance of a real-time multi-task operating system and aided navigation precision requirements, constructing a sliding window data backtracking framework by using historical physical field value matching data, obtaining a rotation transformation matrix from an indication track point set to a closest reference point set by adopting a matrix eigenvalue and eigenvector decomposition method, and moving a sliding window and performing forward and reverse cyclic matching to achieve a global track constraint, thereby improving the matching precision and robustness.

First claim

What is claimed is:

1. A contour line matching method based on sliding window data backtracking,
wherein the method comprises the following steps:
(1) after a vehicle enters a geophysical field adaptation area, measuring and storing a measured physical field value corresponding to a track point through a physical field sensor carried by the vehicle, meanwhile, storing latitude and longitude coordinates of an indication track point output by an inertial navigation system, and extracting a physical field reference database for an area according to information of the latitude and longitude coordinates provided by the inertial navigation system;
(2) extracting latitude and longitude coordinates of a starting point in the physical field reference database obtained in the step (1), and converting the latitude and longitude coordinates of the indication track point output by the inertial navigation system into coordinates of a relative position using the latitude and longitude coordinates of the starting point as an origin;
(3) determining sliding window parameters according to the calculation performance of a real-time multi-task operating system and aided navigation precision requirements;
(4) according to the measured physical field value corresponding to the track point obtained in the step (1) and the coordinates of the relative position of the indication track point obtained in the step (2), extracting a contour line close to the inertial navigation system indication track point in a sliding window determined in the step (3), and searching a corresponding closest reference point from the indication track point in the sliding window to the close contour line;
(5) according to the closest reference point searched in the step (4) and the indication track point in the sliding window, constructing an incidence matrix M, calculating an eigenvalue and a unit eigenvector of a two-order symmetric positive definite matrix S=M T M, and thus determining a rotation matrix R and a translation vector t from an indication track point set to a closest reference point set;
(6) updating the position of the indication track point in the sliding window by using the rotation matrix R and the translation vector t obtained in the step (5), judging whether the number of iterations in the sliding window exceeds the limit or satisfies convergence conditions, executing the step (4) if the number of iterations does not exceed the limit or satisfy the convergence conditions, and otherwise, executing the next step; and
(7) judging whether the forward and reverse cyclic matching times of the sliding window are reached, if not, moving the sliding window according to a sliding window moving step length in the step (3) and executing the step (4), and if yes, completing global optimal track point matching.

2. The contour line matching method based on sliding window data backtracking according to claim 1 , wherein the step (2) specifically comprises:
extracting the latitude and longitude coordinates (λ 0 , L 0 ) of the starting point in the physical field reference database obtained in the step (1), and converting the latitude and longitude coordinates (λ, L) of the indication track point output by the inertial navigation system into the coordinates (pE, pN) of the relative position using the latitude and longitude coordinates (λ 0 , L 0 ) of the starting point as an origin, i.e.:

{

p
E

=

(

λ
-

λ
0

)

×
60
×
1853
×

cos
⁡
(

L
0

×

π
/
180

)

p
N

-

(

L
-

L
0

)

×
60
×
1853

(
1
)

in the formula, λ 0 and L 0 respectively represent the latitude and longitude coordinates of the starting point in the physical field reference database, and the unit is degrees; λ and L respectively represent the latitude and longitude coordinates of the indication track point output by the inertial navigation system, and the unit is degree; and pE and pN respectively represent a relative east coordinate and a relative north coordinate of the indication track point output by the inertial navigation system, and the unit is meter.

3. The contour line matching method based on sliding window data backtracking according to claim 1 , wherein the sliding window parameters in the step (3) comprise a sliding window length N, a sliding window moving step length L and the forward and reverse cyclic matching times IC of the sliding window, wherein N represents the sliding window length, L represents the sliding window moving step length, IC represents the forward and reverse cyclic matching times of the sliding window, N, L and IC are all positive integers and satisfy N≥L.

4. The contour line matching method based on sliding window data backtracking according to claim 1 , wherein the step (4) specifically comprises:
according to the measured physical field value h i in the sliding window, extracting the contour line c i close to the inertial navigation system indication track point p i in the sliding window in the physical field reference database, and searching t

Assignees

• Univ Southeast

Inventors

• Cheng Xianghong
• Ding Peng

Classifications

• G01C21/30 Primary

  Map- or contour-matching · CPC title

• G01C21/165

  combined with non-inertial navigation instruments · CPC title

• G06F17/16 Primary

  Matrix or vector computation {, e.g. matrix-matrix or matrix-vector multiplication, matrix factorization (matrix transposition G06F7/78)} · CPC title

• G01C21/203 Primary

  specially adapted for water-borne vessels · CPC title

• G01C21/04

  by terrestrial means (G01C21/24, G01C21/26 take precedence) · CPC title