Calibration Track Reflectors for RADAR and LIDAR Sensor Alignment

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Solution Overview

Problem

Existing calibration methods for motor vehicle measurement systems, such as RADAR and LIDAR, face challenges in accurately compensating for installation and measuring tolerances, leading to deviations in sensor positioning and performance.

Innovation Solution

A calibration track with a defined arrangement of reflectors along a roadway, allowing the vehicle to drive through and generate measurement data, which is compared to stored calibration data to determine deviations and calculate correction parameters for precise sensor calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If calibration procedures are carried out on the motor vehicle at the end of a production line or regularly in certain states, then the measuring system can be calibrated, but the calibration process becomes complex and time-consuming

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining a calibration path with precisely positioned reflectors before the calibration process. The calibration path is prepared in advance with reflectors arranged at specific locations and orientations, so that when the vehicle traverses the path, the measurement system automatically captures calibration data without requiring complex real-time adjustments or procedures.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple reflectors are arranged along the calibration track, then measurement data can be collected comprehensively, but the setup becomes more complex

Engineering Contradiction:
Improvedetection accuracyVSAvoidreflector arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the calibration task into multiple discrete reflector elements arranged along the calibration path. Each reflector serves as an independent measurement point, and the collection of segmented reflectors provides comprehensive coverage for calibrating the measurement system across different positions and angles, simplifying the overall setup compared to using a single complex calibration target.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If the vehicle travels through the calibration path at different speeds, then calibration can be performed under various operating conditions, but the calibration data becomes inconsistent

Engineering Contradiction:
Improvecalibration condition flexibilityVSAvoidcalibration data consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using the measured positions and characteristics of multiple reflectors to determine the vehicle's actual trajectory and speed variations. This feedback information is then used to correct and normalize the calibration data, compensating for speed variations and ensuring consistent calibration results regardless of the vehicle's travel speed through the calibration path.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly improves the accuracy of object detection relative to the vehicle by compensating for installation and measuring tolerances, enabling easy and precise calibration of RADAR and LIDAR systems.

Implementation Method 1

The reflectors are suitable for the respective measurement system. For a radar system, this might be a triple mirror, also called a corner reflector; for a lidar system, a retroreflector or a plate with a reflective surface.

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3550322B1Calibration line for calibrating a measuring system and a method for calibrating a measuring system
Publication Date: 2023.07.26 ZF FRIEDRICHSHAFEN AG
  • EP3550322B1 patent drawingFigure 1
  • EP3550322B1 patent drawingFigure 2
  • EP3550322B1 patent drawingFigure 3

AI summary

A calibration track (10) for calibrating a measuring system (20) of a motor vehicle (14), comprising a plurality of reflectors (16), and a roadway (12) for the motor vehicle (14), wherein the reflectors (16) are arranged in a defined configuration. Furthermore, a method for calibrating a measuring system (20) on such a calibration track (10) is proposed.