Coherent Radar Processing Chain for Ambiguous Angle Detection

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Solution Overview

Problem

Conventional signal processing algorithms for radar systems with sparse, non-uniform, and large antenna arrays fail to compensate phase shifts, leading to ambiguous angular measurements and low signal-to-noise ratios, which affect the accuracy and efficiency of target detection.

Innovation Solution

A method for determining target information using a radar system with multiple transmitting and receiving antennas, where each antenna transmits a radar signal in successive operations, generating data structures based on received signals, and creating individual range-Doppler-maps to improve signal processing and increase signal-to-noise ratio, allowing for coherent processing of distributed apertures and reducing the number of antennas needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional signal processing algorithms are used for radar systems with sparse, non-uniform, and large antenna arrays, then the system structure is simple, but phase shifts cannot be compensated, leading to ambiguous angular measurements and low signal-to-noise ratios

Engineering Contradiction:
Improveangular measurement accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the signal processing into multiple distinct stages: generating multiple hypotheses for target angles, creating separate data structures for each hypothesis, generating individual range-Doppler-maps for each hypothesis, and finally combining results. This segmentation allows complex phase shift compensation to be handled systematically through multiple simpler processing steps rather than a single complex algorithm.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by generating multiple hypotheses for target angles before actual signal processing. Data structures are pre-organized for each hypothesis, and range-Doppler-maps are generated in advance for each hypothesis. This preliminary organization enables efficient phase shift compensation and angular measurement without requiring complex real-time processing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If conventional signal processing is used, then the processing procedure is simple, but the signal-to-noise ratio is low, affecting detection performance

Engineering Contradiction:
Improvedetection performanceVSAvoidsignal processing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple range-Doppler-maps generated from different hypotheses into a combined result. By coherently combining the results from multiple hypotheses and their corresponding range-Doppler-maps, the signal-to-noise ratio is improved while maintaining detection performance. This merging process integrates information from multiple processing paths to enhance overall reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple transmitting and receiving antennas are used, then angular resolution is improved, but the number of antennas increases system complexity

Engineering Contradiction:
Improveangular resolutionVSAvoidantenna array complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the processing parameters by generating multiple hypotheses for target angles and creating separate data structures for each hypothesis. Instead of directly processing signals from all antennas simultaneously, the system processes signals through multiple hypothesis-based pathways, effectively managing the complexity introduced by multiple antennas while maintaining high angular resolution.

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

Enhances angular resolution, reduces side lobe ambiguity, and improves detection performance by increasing signal-to-noise ratio, enabling accurate and efficient detection of objects in dynamic applications such as automobiles, trains, and ships.

Implementation Method 1

each transmitting antenna of the multiple transmitting antennas transmits a radar signal into an environment of the radar system in successive transmission operation. After each transmitting operation, at least some of the plurality of receiving antennas receive reflected received signals from the radar target

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

The processor obtains a Doppler measurement related to a radial velocity of the object, wherein the Doppler measurement includes a Doppler ambiguity, obtains a range walk rate for the radial velocity of the object, and resolves the Doppler ambiguity of the Doppler measurement using the range walk rate

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4624991A1A method for determining a target information of a radar target based on an coherent signal processing chain, radar system and motor vehicle
Publication Date: 2025.10.01 VOLKSWAGEN AG
  • EP4624991A1 patent drawingFigure 1~2
  • EP4624991A1 patent drawingFigure 3~4
  • EP4624991A1 patent drawingFigure 5~6

AI summary

The present invention relates to a method for determining a target information (67) of a target (15) of a radar system (3), wherein the system (3) comprising transmitting antennas (9) and receiving antennas (10), wherein - each transmitting antenna transmits a radar signal (13) in successive transmission operation, - after each transmitting operation, antennas (10) receive signals (16) based on the transmitted signal (13) of the respective transmitting operation, - multiple hypothesis of target angles with regards to the radar target (15) are specified, - for each hypothesis of a target angle a data structure is generated based on the received signals (16), - for each data structure a range-Doppler-map (48, 49, 50) is generated based on the signals (16), and - the target information (67) is determined based on the range-Doppler-maps (48, 49, 50). Furthermore the present invention relates to a radar system (3) and a motor vehicle (21).