Vehicle Position Estimation Using Dynamic Target Data Adjustment

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Solution Overview

Problem

Conventional vehicle position estimation methods face accuracy issues due to errors in detected passage information, leading to discrepancies between detected and actual passage shapes, which affects the precision of vehicle positioning.

Innovation Solution

A vehicle position estimation device that adjusts target position data within specific ranges to improve matching with map information, using radar devices and cameras to detect curbs and lane markings, and odometry data to calculate travel trajectories, allowing for positional and angular adjustments to enhance estimation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If target position data is used without adjustment for matching with map information, then the processing is simple and fast, but the vehicle position estimation accuracy deteriorates due to errors in detected passage information

Engineering Contradiction:
Improvevehicle position estimation accuracyVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by adjusting target position data before matching with map information. The adjustment process corrects errors in detected passage information (such as curb and lane marking positions) before the matching operation, ensuring that the data is already optimized for accurate vehicle position estimation. This preliminary correction prevents cumulative errors from affecting the final positioning accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by modifying target position data within a calculated adjustment range. The system determines adjustment amounts based on detected passage information and applies corrections to position parameters, allowing the data to adapt to actual conditions while maintaining the benefits of using detected passage data for position estimation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If adjustment range is set too large for target position data, then estimation accuracy may improve, but matching errors increase and vehicle position estimation accuracy deteriorates

Engineering Contradiction:
Improvevehicle position estimation accuracyVSAvoidmatching reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent optimizes the adjustment range parameter by calculating it based on detected passage information and error characteristics. The system dynamically determines appropriate adjustment limits that are large enough to correct typical detection errors but small enough to prevent excessive adjustments that would introduce matching errors. This parameter optimization ensures reliable vehicle position estimation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback mechanisms by using detected passage information to inform the adjustment process. The system continuously monitors matching results and adjusts the adjustment range based on the detected errors, creating a feedback loop that optimizes the balance between correcting detection errors and avoiding over-adjustment that would reduce matching reliability.

Inventive Principle:
Principle #23Feedback

3Productivity

If odometry information is used for position estimation, then continuous position data is available, but cumulative errors increase over time and travel distance

Engineering Contradiction:
Improveposition estimation continuityVSAvoidposition estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using map information as a reference to correct cumulative odometry errors. The system continuously compares adjusted target position data with map information and uses the discrepancies to correct odometry-based position estimates, preventing error accumulation while maintaining continuous position data availability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces map information as an intermediary between odometry data and final position estimation. The map serves as a reference framework that mediates the integration of odometry information with detected passage data, allowing the system to maintain continuous positioning while correcting cumulative errors through periodic reference to the accurate map information.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3343174B1Vehicle position estimation device, vehicle position estimation method
Publication Date: 2020.04.15 NISSAN MOTOR CO LTD
  • EP3343174B1 patent drawingFigure 1
  • EP3343174B1 patent drawingFigure 2
  • EP3343174B1 patent drawingFigure 3

AI summary

In this vehicle position estimation device, positions of a target present in a periphery of a vehicle is detected and, in conjunction therewith, amounts of movements of the vehicle is detected, and the positions of the target is stored as target position data, based on the amounts of movements. In addition, a portion of the target position data are grouped into a group according to turning states of the vehicle, and, based on amounts of movements of the vehicle when the target position data are detected, an adjustment range for the group is set. Further, map information including positions of the target is acquired and, by matching the target position data with the positions of the target in the map information based on the set adjustment range, a vehicle position of the vehicle is estimated.