Time Domain Phase Signal Processing for Moving Object Detection

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Solution Overview

Problem

Existing sensor technologies for detecting moving objects and vital signs in vehicles face challenges in efficiently processing channel impulse responses (CIRs) without transforming them into the frequency domain, which increases power and memory requirements.

Innovation Solution

A moving object detector system that processes CIRs in the time domain, using a phase signal generated from RF pulses to detect moving objects by comparing the phase signal with a target signal, without the need for fast-Fourier transform (FFT), thereby reducing power consumption and memory requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If channel impulse responses are transformed into frequency domain using fast-Fourier transform, then detection accuracy is improved, but power consumption and memory requirements increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the domain parameter from frequency domain to time domain processing. Instead of transforming CIRs to frequency domain using FFT, the system processes CIRs directly in time domain by extracting phase information and comparing with target signals, thereby reducing computational complexity and power consumption while maintaining detection accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts only the necessary phase information from the complete CIR data. By taking out the phase component and comparing it with pre-stored target signals, the system avoids the computationally intensive FFT transformation while still achieving accurate moving object detection

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If channel impulse responses are transformed into frequency domain using fast-Fourier transform, then detection accuracy is improved, but memory requirements increase

Engineering Contradiction:
Improvedetection accuracyVSAvoidmemory requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the processing domain from frequency to time domain, which reduces the memory footprint. Time domain phase extraction requires storing only phase values rather than complete frequency spectrum data, significantly reducing memory requirements while maintaining detection capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts only the essential phase component from the full CIR data structure. By working with extracted phase information in time domain instead of complete frequency domain representations, the system minimizes memory usage while preserving the critical information needed for accurate detection

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables efficient detection of moving objects and vital signs with low power consumption and low memory requirements, allowing for accurate detection of gestures, leg kicks, and vital signs like heart rate and breathing rate without the need for complex frequency domain analysis.

Implementation Method 1

transmitting radio frequency (RF) pulses and receiving RF pulses based on the transmitted RF pulses reflecting from the moving object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

This same sensor technology also exploits Doppler effect to provide motion information that enables sensing a leg kick at a rear bumper of the vehicle

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4080237A1Detecting a moving object based on a phase of channel impulse responses
Publication Date: 2022.10.26 NXP BV
  • EP4080237A1 patent drawingFigure 1
  • EP4080237A1 patent drawingFigure 2
  • EP4080237A1 patent drawingFigure 3A

AI summary

A moving object detector detects a moving object in a channel. The detection comprises the detector receiving a plurality of frames based on a transmitter transmitting a plurality of frames over a channel. One or more channel impulse responses (CIRs) of the channel is determined based on the received plurality of frames. The detector determines a CIR phase for each of the CIRs and a phase signal is formed based on a phase value of the CIR phase for each of the CIRs. The detector compares the phase signal with a target signal and detects the moving object in the channel based on the comparison.