MIMO Radar Sensor Calibration via Model Error Feedback

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Solution Overview

Problem

Radar sensors in vehicles face precision issues due to changes over time caused by factors like temperature fluctuations and vibrations, leading to inaccurate initial calibrations and the need for frequent recalibration or replacement, which is complex and expensive.

Innovation Solution

A device for calibrating MIMO radar sensors that continuously adjusts calibration coefficients based on model errors calculated from angular and channel data, allowing for precise compensation of discrepancies and enabling continuous calibration during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If initial calibration is performed in a measurement chamber, then calibration precision is improved, but the calibration cannot account for changes over time due to temperature fluctuations, moisture, and vibrations

Engineering Contradiction:
Improvecalibration precisionVSAvoidcalibration reliability over time
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary calibration in a measurement chamber to establish baseline calibration coefficients, then continuously updates these coefficients during operation by detecting model errors from actual radar targets. This combines initial precision with ongoing adaptation to environmental changes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors radar target detections and calculates model errors between actual channel responses and expected responses. These model errors provide feedback for updating calibration coefficients, enabling the system to self-correct drift caused by temperature, moisture, and vibrations over time.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If recalibration is performed frequently to maintain precision, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveradar detection precisionVSAvoidrecalibration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The radar sensor system performs self-calibration by automatically detecting model errors from actual targets in its environment and updating its own calibration coefficients without requiring external calibration equipment or manual intervention. This eliminates the complexity of frequent external recalibration procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Instead of periodic recalibration, the system continuously updates calibration coefficients during normal operation whenever targets are detected. This continuous self-adjustment maintains precision without the disruptions and complexities of scheduled recalibration events.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If recalibration is performed frequently to maintain precision, then calibration accuracy is improved, but time consumption and operational downtime increase

Engineering Contradiction:
Improvechannel response accuracyVSAvoidrecalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The calibration update process occurs continuously in the background during normal radar operation, utilizing detected targets for calibration purposes. This eliminates operational downtime associated with periodic recalibration, as the useful action of target detection serves dual purposes: monitoring and calibration.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system performs preliminary calibration in a measurement chamber to establish baseline coefficients, then uses subsequent target detections to incrementally update these coefficients. This approach avoids the need for time-consuming full recalibration procedures by building upon the initial calibration with small, rapid adjustments.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If radar sensors are replaced to maintain precision over long periods, then reliability is improved, but cost and device complexity increase

Engineering Contradiction:
Improvelong-term sensor reliabilityVSAvoidsensor replacement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The radar sensor system extends its own service life by continuously self-calibrating to compensate for degradation from environmental factors. This self-maintenance capability eliminates the need for replacement, improving long-term reliability while reducing the complexity associated with replacement procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The continuous calibration update process acts as a cushion against the effects of aging and environmental degradation. By proactively compensating for drift and degradation through ongoing model error detection and coefficient adjustment, the system prevents performance degradation that would otherwise necessitate replacement.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS12066568B2Device and method for calibrating a multiple-input multiple output radar sensor
Publication Date: 2024.08.20 ZF FRIEDRICHSHAFEN AG
  • US12066568B2 patent drawing
  • US12066568B2 patent drawing
  • US12066568B2 patent drawing

AI summary

A device includes an input interface for receiving a target list for the MIMO radar sensor containing angular data including information regarding a target angle, at which the target is located, and channel data including information regarding reflection signals received from the target in individual channels in the MIMO radar sensor; a modeling unit for generating model data for each of the targets; a processor for determining a model error for each of the targets, containing information regarding a discrepancy between the channel data and the model data for the target; a selector for selecting one of the targets on the basis of the model error; and an adjustment unit for determining calibration coefficients for adjusting the channel outputs in the MIMO radar that compensate for the discrepancies between the channel data and the model data.