Radar Phase Analysis for Multi-Target Discrimination

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Solution Overview

Problem

Automotive radar systems face performance limitations in discriminating multiple objects with similar position and Doppler characteristics, leading to difficulties in identifying smaller objects masked by larger ones, such as pedestrians or motorcycles near larger vehicles, due to noise suppression techniques that degrade signal information.

Innovation Solution

The implementation of a local phase spectrum evaluation technique, which analyzes the phase differences across antenna elements to distinguish single from multiple scattering centers, enhancing the detection of multiple near objects by evaluating the phase difference variance and standard deviation, and triggering more advanced parameter estimation techniques when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-coherent integration (NCI) amplitude profile detection is used, then noise suppression is improved and false alarms are reduced, but the ability to discriminate multiple objects with similar position and Doppler characteristics deteriorates

Engineering Contradiction:
Improvefalse alarm reductionVSAvoidmulti-object discrimination capability
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent transitions from 2D range-Doppler analysis to 3D range-Doppler-angle analysis by incorporating phase information from multiple receive antennas. This dimensional expansion enables discrimination of multiple objects that occupy similar range-Doppler cells but differ in their angular positions, thereby resolving the masking effect while preserving noise suppression benefits

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the detection parameter from amplitude-only (NCI) to include phase information. By analyzing phase differences across receive antennas, the system can distinguish between multiple scatterers within the same range-Doppler cell, improving multi-object discrimination without sacrificing the noise suppression advantages of NCI

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If narrow beam antenna design is used, then multi-target discrimination is improved, but sensor size and cost increase

Engineering Contradiction:
Improvemulti-target discriminationVSAvoidsensor size and cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of using narrow beam antennas (spatial filtering), the patent uses phase analysis to extract angular information from a broader beam. This software-based approach achieves multi-target discrimination without requiring physically narrow beams, thus avoiding increased sensor size and cost

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent replaces the mechanical/solution of narrow beam antenna design with a signal processing solution based on phase analysis. This substitution achieves the same discrimination function through digital processing rather than physical antenna constraints, reducing sensor complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If revised waveform parameter specification is used, then multi-target detection is improved, but signal processing complexity increases

Engineering Contradiction:
Improvemulti-target detection capabilityVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the detection parameter from amplitude to phase, enabling multi-target detection using standard waveform parameters and existing signal processing pipelines. This approach improves detection capability without requiring waveform redesign or complex additional processing

Inventive Principle:
Principle #35Parameter changes

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 improves the radar system's ability to accurately identify and classify multiple near objects, reducing false alarms and enhancing object tracking capabilities, especially in scenarios with inadequate signal-to-noise ratios, while optimizing signal processing resources.

Implementation Method 1

a plurality of antennas configured to detect a reflected radar signal reflected by an object

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Doppler parameters (i.e. range-rate) of detected objects

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP2998761B1Radar system with phase based multi-target detection
Publication Date: 2020.01.01 APTIV TECHNOLOGIES LTD
  • EP2998761B1 patent drawingFigure 1
  • EP2998761B1 patent drawingFigure 2
  • EP2998761B1 patent drawingFigure 3

AI summary

A radar system (10) includes a plurality of antennas (16) and a controller (26). The plurality of antennas (16) is configured to detect a reflected radar signal (20) reflected by an object (24A) in a field-of-view (22) of the system (10). Each antenna (16A) of the plurality of antennas (16) is configured to output a detected signal (30) indicative of the reflected radar signal (20) detected by the antenna (16A). The controller (26) is configured to receive detected signals (30) from the plurality of antennas (16), and determine if a target (24) is present in the field-of-view (22) based on the detected signals (30). The controller (26) is also configured to determine if the target (24) includes more than one object (24A) based on an analysis of phases of the detected signals (30).