Smart Radar Symmetric Doppler Interference Mitigation

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Solution Overview

Problem

Radar systems integrated into consumer devices face challenges such as size and layout constraints, interference from other components, and motion of the device, leading to false detections and inability to detect desired objects obscured by interference artifacts.

Innovation Solution

A smart-device-based radar system employs symmetric Doppler interference mitigation to filter interference artifacts caused by vibrations, exploiting the symmetric amplitude contributions across the Doppler spectrum to attenuate interference without affecting desired object reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the radar system operates in a consumer device with vibrations, then the radar can detect objects in compact form factor, but interference artifacts cause false detections and mask desired objects

Engineering Contradiction:
Improvedetection accuracyVSAvoidinterference artifact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by differentiating between symmetric interference artifacts (which appear equally in positive and negative Doppler bins) and asymmetric target reflections (which appear predominantly in one Doppler direction). The processing selectively attenuates the symmetric interference components while preserving asymmetric target signals, resolving the contradiction between detecting objects and filtering interference.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent converts the harmful vibration interference into a beneficial filtering mechanism by exploiting its symmetric Doppler signature. The interference artifact's symmetry across Doppler bins becomes the key characteristic for identification and selective attenuation, transforming the harmful vibration effect into a useful discrimination feature that enhances detection reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If symmetric Doppler interference mitigation is applied to filter interference artifacts, then false detections are reduced, but the filtering must not attenuate reflections from desired objects

Engineering Contradiction:
Improvefalse detection rateVSAvoidtarget reflection signal
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent uses asymmetry to preserve target reflections during filtering. Since desired objects typically produce asymmetric Doppler signatures (moving predominantly in one direction), the filtering process maintains these asymmetric components while removing symmetric interference, thus reducing false detections without losing target information.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by performing selective attenuation at specific Doppler bin locations where symmetric interference is identified. The filtering is applied locally to positive and negative Doppler bins based on their individual amplitude characteristics, allowing precise removal of interference while preserving target signals in different Doppler regions.

Inventive Principle:
Principle #3Local quality

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 radar system effectively reduces false detections and improves object detection accuracy by incorporating interference artifacts into the noise floor, allowing for reliable detection of objects even in the presence of vibrations.

Implementation Method 1

Radars are useful devices that can detect objects

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

reflections from the desired object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

symmetric Doppler interference mitigation

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4078212B1Smart-device-based radar system performing symmetric doppler interference mitigation
Publication Date: 2025.02.12 GOOGLE LLC
  • EP4078212B1 patent drawingFigure 1
  • EP4078212B1 patent drawingFigure 2-1
  • EP4078212B1 patent drawingFigure 2-2

AI summary

Techniques and apparatuses are described that implement a smart-device-based radar system capable of performing symmetric Doppler interference mitigation. The radar system employs symmetric Doppler interference mitigation to filter interference artifacts (706) caused by the vibration of the radar system or the vibration other objects. This filtering operation incorporates the interference artifact (706) within the noise floor, without significantly attenuating reflections from a desired object. This mitigation can filter each radar frame independently without a priori knowledge about the frequency or amplitude of the vibration. The filtering operation is also independent of the Doppler sampling frequency and can handle aliasing. By filtering the interference artifacts (706), the radar system produces fewer false detections in the presence of vibrations and can detect objects that would otherwise be masked by the interference artifact (706).