Radar Sensor Synchronization via Phase Detectors

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Solution Overview

Problem

Radar sensors for autonomous driving face challenges in synchronizing high-frequency modules due to temperature-dependent phase differences, which can lead to unreliable signal processing and increased complexity with multiple transmission and reception channels.

Innovation Solution

The implementation of phase detectors and phase sliders in each high-frequency module allows for precise adjustment of temperature-dependent phase differences, ensuring accurate synchronization of the modules without compromising the radar sensor's functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of high-frequency components (MMICs) is increased to implement MIMO or digital beamforming concepts, then the radar sensor's functionality and measurement precision are improved, but the device complexity and spatial distances between components increase, leading to temperature-dependent phase differences that worsen synchronization reliability

Engineering Contradiction:
Improvesynchronization precisionVSAvoidnumber of high-frequency components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A feedback loop is implemented consisting of a phase detector, phase shifter, and control device. The phase detector monitors the phase difference between synchronization signals from different MMICs, the control device processes this information, and the phase shifter adjusts the phase to compensate for temperature-dependent variations. This closed-loop feedback system automatically maintains synchronization precision despite temperature changes and increased component count.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

An intermediary synchronization signal path is introduced between the high-frequency components. This intermediary path includes the phase detector and phase shifter that mediate the synchronization process, allowing indirect measurement and adjustment of phase differences without requiring direct comparison between all MMIC pairs, thus managing complexity while maintaining precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the spatial distances between individual MMICs increase to accommodate more components, then the radar sensor can process more channels, but the propagation times of synchronization signals become significant and temperature variations cause unknown phase differences that deteriorate synchronization accuracy

Engineering Contradiction:
Improvenumber of transmission and reception channelsVSAvoidphase difference accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The feedback mechanism continuously monitors phase differences through the phase detector and automatically compensates for propagation time variations and temperature effects using the phase shifter. This real-time adjustment maintains phase difference accuracy despite increased spatial distances between MMICs, enabling more channels without sacrificing synchronization precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes the phase parameter using the phase shifter to compensate for temperature-dependent phase differences. By adjusting the phase parameter in real-time based on feedback from the phase detector, the system maintains accurate synchronization even as spatial distances between components increase to accommodate more channels.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If phase detectors and phase shifters are added to each high-frequency component for temperature compensation, then synchronization accuracy is improved, but the device complexity and power dissipation increase

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidcomponents per high-frequency module
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The phase detector and phase shifter are designed to perform multiple functions: they not only compensate for temperature-dependent phase differences but also facilitate synchronization between all MMICs. This multi-functionality reduces the need for additional dedicated components, thereby improving reliability without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Each high-frequency component with added phase detectors and phase shifters becomes self-regulating regarding its phase synchronization. The components automatically adjust their own phase characteristics based on local temperature conditions and feedback from the phase detector, reducing the need for external control complexity while improving overall synchronization reliability.

Inventive Principle:
Principle #25Self-service

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 solution enables precise synchronization of high-frequency modules, accounting for temperature-dependent phase differences, thereby enhancing the reliability and accuracy of radar sensors for autonomous driving applications.

Implementation Method 1

a phase detector is connected in parallel to the signal path, which phase detector supplies a signal which assumes an extremum at a certain known phase difference, independent of temperature

Methodology Applied
Scientific EffectPhase detection:

Implementation Method 2

a phase shifter is arranged in the signal path, with which the phase difference can be adjusted such that the signal of the phase detector assumes the extremum

Methodology Applied
Scientific EffectPhase shifting:

Data Source

PatentEP3857255B1Radar sensor having synchronized high-frequency modules
Publication Date: 2025.05.14 ROBERT BOSCH GMBH
  • EP3857255B1 patent drawingFigure 1
  • EP3857255B1 patent drawingFigure 2
  • EP3857255B1 patent drawing

AI summary

The invention relates to a radar sensor having at least two synchronized high-frequency modules (10, 12), each having at least one signal path (TX1, TST1; TX2, TST2), wherein the phase of the transmitted high-frequency signal is modified by a temperature-dependent phase difference, characterized in that a phase detector (28) is connected parallel to the signal path (TX1, TST1; TX2, TST2) in each high-frequency module (10, 12), said phase detector supplying a signal (U), which, independently of temperature, assumes an extreme value in the case of a specific phase difference, and that a phase shifter (24), by means of which the phase difference is adjustable such that the signal (U) of the phase detector assumes the extreme value, is arranged in the signal path (TX1, TST1; TX2, TST2).