Vehicle Position Estimation Using Intersecting Landmark Angles

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Solution Overview

Problem

Existing vehicle position estimation methods using two-dimensional landmark information can lead to decreased accuracy when linear routes continue for a predetermined distance with landmarks described as straight lines parallel to the route, resulting in ambiguity in direction and reduced estimation precision.

Innovation Solution

An own-position estimation device selects landmark position data based on angles formed by intersecting straight lines, matching this data with map information to enhance vehicle positioning accuracy by prioritizing combinations of straight lines with smaller angles and recent data points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If straight lines parallel to the route are used for landmark description, then the cost of creating map information and processing load are reduced, but the accuracy of own-position estimation decreases due to directional ambiguity

Engineering Contradiction:
Improvecost of creating map informationVSAvoidaccuracy of own-position estimation
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the parameter of landmark description from simple straight lines to straight lines with associated angle information. By extracting and utilizing the angles formed by intersecting straight lines, the system maintains the simplicity of 2D map information while adding directional context that resolves ambiguity in position estimation.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If straight lines parallel to the route are used for landmark description, then the processing load of own-position estimation is reduced, but the accuracy of own-position estimation decreases due to directional ambiguity

Engineering Contradiction:
Improveprocessing load of own-position estimationVSAvoidaccuracy of own-position estimation
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent adds angle information as a new parameter to the straight line landmark data. This allows the system to maintain low processing complexity while incorporating directional information that significantly improves position estimation accuracy by eliminating ambiguity along parallel routes.

Inventive Principle:
Principle #35Parameter changes

3Speed

If landmark information is used within a predetermined distance from the latest own position, then real-time estimation is maintained, but accuracy decreases when linear routes continue for predetermined distance with parallel landmarks

Engineering Contradiction:
Improvereal-time estimation speedVSAvoidaccuracy of own-position estimation
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent introduces angle information as an additional dimension to the landmark data. This angular parameter provides a new perspective for discrimination that helps resolve ambiguity in linear routes, allowing the system to maintain real-time performance while improving accuracy through enhanced feature differentiation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3324152B1Own-position estimating device and own-position estimating method
Publication Date: 2019.04.03 NISSAN MOTOR CO LTD
  • EP3324152B1 patent drawingFigure 1
  • EP3324152B1 patent drawingFigure 2
  • EP3324152B1 patent drawingFigure 3

AI summary

An own-position estimation device: detects positions of landmarks present around a vehicle; accumulates the detected positions of the landmarks as landmark position data based on a movement amount of the vehicle; extracts straight lines from the accumulated landmark position data; selects pieces of the landmark position data used for own-position estimation based on angles formed by intersecting ones of the extracted straight lines; and estimates a position of the vehicle by matching the selected pieces of the landmark position data and positions of landmarks in map information.