Optical Clock Synchronization for Multi-Module Automotive Radar

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Solution Overview

Problem

Current automotive radar systems lack the capability to synchronize multiple radar sensor modules effectively, limiting the resolution and functionality of Advanced Driver Assistance Systems (ADAS) due to the limitations of electromagnetic signal performance in providing synchronization.

Innovation Solution

An automotive radar system utilizing optical fibers to distribute a digital clock signal among radar modules, enabling synchronization through a daisy-chain or star network configuration, where a master module generates and transmits a digital clock signal via optical fibers to other modules, allowing them to maintain synchronization and improve imaging resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic signals are used to synchronize radar sensor modules, then the system can be implemented with conventional components, but the synchronization performance and imaging resolution are insufficient

Engineering Contradiction:
Improveimaging resolutionVSAvoidsynchronization performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces electromagnetic signal-based synchronization with an optical synchronization system using optical fibers and TDCs (Time-to-Digital Converters). This substitution of the synchronization mechanism from electromagnetic to optical domain enables higher precision time measurement and better synchronization performance, directly improving imaging resolution while maintaining system reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple radar sensor modules are deployed to improve imaging resolution, then the scanning capability is enhanced, but the synchronization between modules becomes more difficult to maintain

Engineering Contradiction:
Improveimaging resolutionVSAvoidsynchronization complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the synchronization function into independent TDC units at each radar module, with each TDC locally measuring time differences between optical synchronization signals. This segmentation allows each module to autonomously achieve precise synchronization without complex centralized control, enabling multiple modules to be deployed while maintaining synchronization and improving imaging resolution.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If optical fibers are used to distribute clock signals, then synchronization precision is improved, but the system complexity and cost increase

Engineering Contradiction:
Improvesynchronization precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces optical fibers as intermediary transmission media to carry synchronization signals between radar modules. Each module includes an optical receiver that converts optical signals to electrical signals for local TDC processing. This intermediary optical transmission system achieves high-precision synchronization while distributing complexity across multiple independent modules rather than requiring a complex centralized system.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The system achieves improved imaging resolution by synchronizing radar modules, enhancing the performance of ADAS systems in detecting obstacles and providing better environmental scanning.

Implementation Method 1

a digital clock signal is distributed using optical fibres from a master radar module to a number of slave radar modules

Methodology Applied
Scientific EffectOptical signal transmission: Optical Fibre

Data Source

PatentEP3418764B1Automotive radar system and method of synchronising an automotive radar system
Publication Date: 2026.03.18 NXP BV
  • EP3418764B1 patent drawingFigure 1~4
  • EP3418764B1 patent drawingFigure 2
  • EP3418764B1 patent drawingFigure 3

AI summary

An automotive radar system comprises: a master module (110), a first radar module (104), a second radar module (106), and an optical waveguide arrangement (108, 112, 116, 120, 124, 126) operably coupling the master module (110) to the first and second radar modules (104, 106). The master module (110) comprises an electro-optical interface device (228) having an electrical domain side and an optical domain side. The optical domain side is operably coupled to the optical waveguide arrangement (108, 112, 116, 120, 124, 126). The master module (110) comprises a digital clock signal generator (210) operably coupled to the electrical domain side of the electro-optical interface device (228).