Radar Calibration via Inverse Modulation and Signal Integration

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Solution Overview

Problem

Radar sensor systems require accurate calibration to account for variations in vehicle components and manufacturing, but existing methods using anechoic chambers and Doppler modulating transponders are costly and difficult to implement, especially due to space and relocation challenges.

Innovation Solution

A method involving a target object with a modulating transceiver using a first modulation, and a radar transceiver with a second modulation configured to invert the first modulation and have a zero mean value, allowing for calibration in a near-static environment without the need for anechoic chambers or costly Doppler modulators, thereby suppressing interference and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radar calibration is performed using anechoic chambers, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveradar calibration accuracyVSAvoidanechoic chamber infrastructure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential calibration function from the complex anechoic chamber environment by using a portable target object with modulating transceiver that can be deployed in ordinary environments. The target object incorporates modulation capabilities directly, eliminating the need for complex absorption materials and specialized chamber infrastructure while maintaining calibration precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a modulating transceiver as an intermediary component between the radar sensor and the calibration target. This transceiver applies modulation to the reflected signal, enabling precise calibration measurements without requiring anechoic chamber conditions. The modulation technique acts as a mediator that allows accurate calibration in simpler environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If Doppler modulating target transponders are used for calibration, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidimplementation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs a target object with modulating transceiver that uses simpler, less expensive modulation techniques compared to Doppler modulating transponders. The system uses binary phase shift keying (BPSK) or similar simple modulations that are cheaper to implement while still providing sufficient calibration precision for the application.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the modulation parameter from complex Doppler modulation to simpler phase or frequency shift keying. This parameter change reduces the manufacturing complexity and cost of the target transponder while maintaining the ability to provide accurate calibration data through the modulated reflected signal.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If anechoic chambers are used for calibration, then interference is suppressed, but relocation difficulty increases

Engineering Contradiction:
Improveinterference suppressionVSAvoidrelocation ease
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent segments the calibration system into a portable target object with modulating transceiver that can be independently deployed and relocated. This segmentation allows the calibration function to be separated from the fixed anechoic chamber infrastructure, enabling easy relocation while maintaining interference suppression through the modulation technique.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses periodic modulation signals from the target transceiver to suppress interference through coherent integration. The periodic nature of the modulation allows the radar system to distinguish the target signal from random interference, achieving interference suppression without requiring fixed anechoic chamber structures that hinder relocation.

Inventive Principle:
Principle #19Periodic action

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

Enables accurate radar transceiver calibration in a cost-efficient manner without the need for anechoic chambers or expensive Doppler modulating target transponders, allowing for easy relocation of calibration systems and improved signal-to-noise energy ratio by suppressing interference.

Implementation Method 1

configuring a target object with a modulating transceiver associated with a first modulation

Methodology Applied
Scientific EffectPhase shift keying modulation: Phase Modulation

Implementation Method 2

The modulation is by means of frequency shift keying (FSK) or phase shift keying (PSK)

Methodology Applied
Scientific EffectFrequency shift keying modulation: Phase Modulation

Implementation Method 3

configuring the radar transceiver with a modulator associated with a second modulation configured to invert the first modulation and having a zero mean value

Methodology Applied
Scientific EffectInverse modulation: Phase Modulation

Implementation Method 4

integrating an output signal of the modulator to generate an integrated received radar signal

Methodology Applied
Scientific EffectSignal integration:

Implementation Method 5

an interference source not configured with the first modulation is suppressed due to the integrating of a zero-mean modulated signal

Methodology Applied
Scientific EffectInterference suppression through integration: Interference

Data Source

PatentEP3502740B1Radar calibration in a near-static environment
Publication Date: 2020.10.28 VEONEER SWEDEN AB
  • EP3502740B1 patent drawingFigure 1
  • EP3502740B1 patent drawingFigure 2
  • EP3502740B1 patent drawingFigure 3

AI summary

A method for calibrating a radar transceiver comprising configuring a target object with a modulating transceiver associated with a first modulation, configuring the radar transceiver with a modulator associated with a second modulation configured to invert the first modulation and having a zero mean value, wherein the modulator is arranged to modulate an output of an analog to digital converter, ADC, of the radar transceiver, integrating an output signal of the modulator to generate an integrated received radar signal corresponding to a radar detection of the target object, and determining a calibration parameter of the radar transceiver based on the integrated received radar signal.