FMCW Radar Target Detection via Range-Chirp Curve Analysis

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Solution Overview

Problem

Traditional target detection methods using range-Doppler maps in FMCW radar systems are ineffective in detecting weaker targets and require separate steps for detection and classification, which can lead to missed detections and incorrect target separation.

Innovation Solution

The method involves processing reflections to obtain a range-chirp map, performing curve detection using a Hough transform, and applying a Doppler FFT to candidate curves, allowing for the detection of targets based on energy distribution and relative velocity, thereby improving the detection of weaker targets and recognizing multiple returns as associated with a single object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional range-Doppler map detection is used, then the detection process is simple, but weaker targets cannot be detected effectively

Engineering Contradiction:
Improvedetection effectivenessVSAvoiddetection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the detection process into two distinct stages: curve detection in the range-chirp map followed by Doppler analysis. This segmentation allows the system to first identify potential target trajectories through curve detection, then apply Doppler filtering to confirm targets, thereby improving detection reliability for weak targets while maintaining manageable complexity through structured processing steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary curve detection on the range-chirp map before applying Doppler analysis. By pre-identifying candidate target trajectories through curve detection algorithms, the system prepares the data structure in advance, allowing subsequent Doppler processing to focus only on relevant candidates, thus improving overall detection effectiveness without proportionally increasing complexity.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If separate target detection and classification steps are used, then each step can be optimized independently, but target separation becomes incorrect and detections are missed

Engineering Contradiction:
Improvetarget classification accuracyVSAvoidtarget detection reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent merges target detection and classification into a unified process by performing curve detection that simultaneously identifies target presence and extracts trajectory characteristics. The curve fitting process inherently classifies targets by their motion patterns while detecting them, eliminating the need for separate steps and preventing missed detections or incorrect separations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The curve detection algorithm serves multiple functions simultaneously: it detects target presence, determines target trajectory, and provides initial classification information. This multi-functional approach ensures that detection and classification reinforce each other rather than work at cross-purposes, improving both accuracy and reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If curve detection is performed on range-chirp map, then weaker targets are detected better, but processing complexity increases

Engineering Contradiction:
Improveweak target detectionVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curve detection selectively to regions of the range-chirp map where targets are likely to appear, rather than processing the entire map uniformly. By focusing computational resources on local regions with potential target signatures, the system improves weak target detection while limiting the increase in overall processing complexity through localized analysis.

Inventive Principle:
Principle #3Local quality

4Loss of information

If Doppler FFT is applied to candidate curves, then target velocity information is obtained, but processing time increases

Engineering Contradiction:
Improvevelocity information retentionVSAvoidprocessing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent applies Doppler FFT only to candidate curves that have been pre-identified through curve detection, rather than processing all data points. This partial action approach ensures that velocity information is extracted from relevant targets while minimizing processing time by excluding non-target regions from the computationally intensive Doppler analysis.

Inventive Principle:
Principle #16Partial or excessive action

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 enhances the detection of weaker targets and improves target separation by using a range-chirp map for curve detection and Doppler FFT, facilitating joint target detection and classification.

Implementation Method 1

A shift in the frequencies of received reflections from the transmitted frequencies results from relative movement of the reflecting target and is referred to as the Doppler shift.

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

performing a fast Fourier transform to obtain an indication of energy distribution of the reflections at each detectable range associated with each of the chirps

Methodology Applied
Scientific EffectFast Fourier transform:

Implementation Method 3

performing the curve detection includes using a Hough transform on the range-chirp map for each beam

Methodology Applied
Scientific EffectHough transform:

Data Source

PatentUS10794991B2Target detection based on curve detection in range-chirp map
Publication Date: 2020.10.06 GM GLOBAL TECHNOLOGY OPERATIONS LLC
  • US10794991B2 patent drawing
  • US10794991B2 patent drawing
  • US10794991B2 patent drawing

AI summary

A system and method to perform target detection includes transmitting frequency modulated continuous wave (FMCW) pulses as chirps from a radar system. The method also includes receiving reflections resulting from the chirps, and processing the reflections to obtain a range-chirp map for each beam associated with the transmitting. Curve detection is performed on the range-chirp map for each beam, and one or more targets is detected based on the curve detection.