In-Vehicle Radar Interference Mitigation via Dynamic Frequency Shifting

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Solution Overview

Problem

In-vehicle radar systems face interference challenges when using multifrequency CW radar waves, particularly when overlapping with CW waves from other vehicles, making it difficult to employ software waveform shaping to mitigate interference effects.

Innovation Solution

An in-vehicle radar apparatus with interference determination, selection, and frequency changing means to identify and address interference between multifrequency CWs by determining the interfering party and adjusting the center frequency of the own vehicle's multifrequency CW radar waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If software waveform shaping is used to reduce interference influence, then interference mitigation is improved for FMCW, but it becomes ineffective when multifrequency CW interferes with another CW wave

Engineering Contradiction:

Improveinterference influenceVSAvoidapplicability to different radar types

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent changes the frequency parameter of the radar wave by shifting the center frequency of the multifrequency CW when interference is detected. This allows the system to adapt to different interference scenarios (FMCW or CW) by dynamically adjusting the operating frequency, thereby resolving the limitation of software waveform shaping that only works for FMCW.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If multifrequency CW is used for radar operation, then continuous wave operation benefits are achieved, but interference with other CW radars persists during overlapping transmission periods

Engineering Contradiction:

Improvecontinuous operation capabilityVSAvoidinterference during overlapping periods

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces dynamic frequency adjustment capability to the multifrequency CW system. When interference is detected, the center frequency is dynamically changed to avoid the interfering signal. This maintains the continuous wave operation benefits while adding adaptability to eliminate interference during overlapping transmission periods.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

By changing the center frequency parameter of the multifrequency CW when interference occurs, the system maintains continuous operation while avoiding the harmful interference effects that would otherwise persist during overlapping transmission periods.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If interference determination and frequency changing means are added, then interference mitigation capability is improved, but device complexity increases

Engineering Contradiction:

Improveinterference reduction capabilityVSAvoidsystem structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where the beat signal is analyzed to detect interference, and based on this detection, the center frequency is automatically adjusted. This closed-loop control achieves effective interference mitigation without requiring complex additional hardware, as the frequency adjustment is triggered by the interference detection feedback.

Inventive Principle:

Principle #23Feedback

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

Effectively reduces the influence of interference, allowing for accurate target detection even in scenarios where vehicles with similar radar systems are nearby, enhancing the reliability of detection results.

Implementation Method 1

a target detection unit that detects a target based on a time difference of flight

Methodology Applied

Scientific EffectTime difference of flight: Time of Flight

Implementation Method 2

a beat signal generated by mixing a transmission signal and a received signal

Methodology Applied

Scientific EffectBeat signal generation through mixing: Beat (acoustics)

Data Source

PatentUS10746848B2In-vehicle radar apparatus

Publication Date: 2020.08.18 DENSO CORP

AI summary

An in-vehicle radar apparatus includes an interference determination means, a selection means, and a frequency changing means. The interference determination means determines presence or absence of interference between multifrequency CWs, which are radar waves, based on a beat signal generated by mixing a transmission signal and a received signal, which are radar waves. The selection means selects an own vehicle or an other-side apparatus, which is a party of the interference, according to an occurrence state of the interference, when the interference determination means determines that the interference is present. The frequency changing means that changes a center frequency of the multifrequency CW transmitted from the own vehicle, when the selection means selects the own vehicle.