FMCW Radar Peak Frequency Detection Threshold Adaptation

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Solution Overview

Problem

Existing FMCW radar systems face instability in detecting target objects due to changes in environmental conditions and the inability to accurately reflect leakage noise in peak detecting threshold calculations, leading to inaccuracy in target object detection.

Innovation Solution

A method is introduced to determine a peak detecting threshold by analyzing a CW noise spectrum and adding an offset to the high-frequency region, and separately adjusting the receiver noise spectrum in the low-frequency region to account for leakage noise, ensuring accurate threshold determination regardless of environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the peak detecting threshold is determined using frequency analysis results from which the peak frequency component is extracted, then the threshold can be adapted to environmental conditions, but the threshold becomes unstable and detection accuracy decreases

Engineering Contradiction:

Improvethreshold adaptation to environmental conditionsVSAvoidpeak frequency detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the frequency spectrum into multiple frequency regions (e.g., first frequency region, second frequency region, third frequency region) and determines different peak detecting thresholds for each region. This allows the threshold to be adapted to environmental conditions in each specific frequency band while maintaining stability through separate processing, resolving the contradiction between adaptability and precision.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the transmitter is deactivated to measure noise level, then receiver noise can be measured, but leakage noise is not reflected leading to inaccurate threshold calculation

Engineering Contradiction:

Improvereceiver noise measurement accuracyVSAvoidthreshold calculation accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent performs preliminary measurement of the noise spectrum with the transmitter activated before determining the peak detecting threshold. This preliminary action captures both receiver noise and leakage noise components, ensuring the threshold calculation reflects actual operating conditions. The noise spectrum obtained this way serves as the basis for accurate threshold determination without requiring transmitter shutdown.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If antennas with low transmitter-to-receiver isolation are used to downsize the antenna or reduce cost, then the radar becomes more compact and affordable, but leakage noise increases to a level that cannot be ignored

Engineering Contradiction:

Improveantenna size and production costVSAvoidleakage noise level

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful leakage noise into a useful measurement component by including it in the noise spectrum measurement with the transmitter activated. The leakage noise, which would normally degrade performance, is now captured and used to establish an accurate baseline for threshold determination. This approach transforms the harmful effect into a beneficial reference for detecting actual target echoes.

Inventive Principle:

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

4Ease of operation

If the peak detecting threshold is determined using frequency components around a specified frequency component, then the threshold can be calculated, but great changes in environmental conditions cause great changes in the threshold leading to instability

Engineering Contradiction:

Improvethreshold calculation capabilityVSAvoidthreshold stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by determining peak detecting thresholds specifically for each frequency region rather than using a single global threshold. Each frequency region (first, second, third regions) has its own threshold determined from the noise spectrum characteristics of that region. This localized approach maintains threshold stability within each region while allowing overall adaptability across different frequency bands.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9110152B2Method of determining threshold for detection of peak frequency in radar and object information producing apparatus using the same

Publication Date: 2015.08.18 DENSO CORP

AI summary

A peak detecting threshold determining method is provided which determines a peak detecting threshold which is used by an FMCW radar in detecting a peak frequency component which appears as representing a target object in a frequency spectrum. A CW radar wave is transmitted to produce a CW noise spectrum. An offset is added to frequency components in a high-frequency region of the CW noise spectrum to define a first distribution as a value of the peak detecting threshold. This enables the value of the peak detecting threshold in the high-frequency region to be determined with high precision by reflecting a receiver noise containing a leakage noise.