Dual-Frequency Radar Modules for Pedestrian Detection Stability

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Solution Overview

Problem

Conventional radar systems face challenges in stably detecting targets with many dominant scattering points, such as pedestrians, due to multipath fading issues in millimeter-wave bands, where the human body acts as a complex scattering body with multiple scattering points, leading to reduced reflection intensity and difficulty in maintaining detection stability.

Innovation Solution

The radar apparatus employs two radar modules operating on different frequency bands, with overlapping main beam directivity, to utilize frequency diversity and suppress fading variations through signal processing, ensuring stable detection of targets with many scattering points by combining outputs from the first and second radar modules, which use distinct frequency channels to enhance signal-to-noise ratio and distance resolving performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single radar module operates in millimeter-wave band to detect targets, then the angular resolution and detection capability are improved, but the detection stability deteriorates due to multipath fading when targets have many scattering points

Engineering Contradiction:
Improveangular resolutionVSAvoiddetection stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The radar system is divided into multiple radar modules (first radar module and second radar module), each operating in different frequency bands. This segmentation allows the system to process signals from multiple frequency channels independently and combine them, thereby reducing the impact of multipath fading on detection stability while maintaining high angular resolution capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the frequency band parameter by operating multiple radar modules at different frequencies (e.g., first module at 76-77GHz, second module at 78-79GHz). This parameter variation enables frequency diversity, where signals experiencing fading at one frequency may be received strongly at another, thus improving overall detection stability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple radar modules operate in different frequency bands, then the frequency diversity gain and detection stability are improved, but the device complexity increases

Engineering Contradiction:
Improvedetection stabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the outputs of multiple radar modules operating in different frequency bands through signal processing. By combining the detection results from the first and second radar modules, the system achieves frequency diversity gain and improved detection stability while managing the complexity through integrated processing architecture

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the main beam directivity of multiple radar modules overlaps, then the frequency diversity gain is enhanced, but the interference between modules increases

Engineering Contradiction:
Improvefrequency diversity gainVSAvoidinterference between modules
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the frequency band parameter for each radar module to operate at different frequencies (e.g., first module at 76-77GHz, second module at 78-79GHz). This frequency separation reduces mutual interference between modules while their main beam directivities overlap in space, enabling effective frequency diversity gain

Inventive Principle:
Principle #35Parameter changes

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 approach allows for stable detection of targets with many dominant scattering points, such as pedestrians, by achieving a high frequency diversity gain and suppressing fading variations, enabling accurate detection even at varying distances and reducing interference with other radar systems.

Implementation Method 1

a first radar transmitter and receiver which transmits a radio-frequency first radar transmission signal generated using a prescribed first transmission code sequence and the first carrier wave

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

which receives a first radar reflection signal produced as a result of reflection of the first radar transmission signal by a target

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a second radar transmitter and receiver which transmits a radio-frequency second radar transmission signal generated using a prescribed second transmission code sequence and the second carrier wave

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 4

which receives a second radar reflection signal produced as a result of reflection of the second radar transmission signal by a target

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2977784B1Radar device
Publication Date: 2018.08.01 PANASONIC HOLDINGS CORP
  • EP2977784B1 patent drawingFigure 1
  • EP2977784B1 patent drawingFigure 2
  • EP2977784B1 patent drawingFigure 3

AI summary

First and second radar modules include channel controllers which set different frequency bands for first and second carrier waves, respectively, and first radar transmitter and receiver which transmit radio-frequency first and second radar transmission signals generated using prescribed first and second transmission code sequences and the first and second carrier waves, which receive first and second radar reflection signals produced as a result of reflection of the first and second radar transmission signals by a target, and which convert them into baseband first and second reception signals. A signal processor performs prescribed combining processing on outputs of the first and second radar modules. The first and second radar transmission signals partially overlap with each other in main beam directivity.