Radar Angle of Arrival Ambiguity Resolution via Doppler Matching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Wide aperture radar systems experience angle of arrival ambiguity due to increased spacing between receivers, which results in phase differences exceeding π, leading to ambiguous angle measurements.

Innovation Solution

The method involves receiving reflections at multiple transceiver nodes, determining candidate angles based on phase differences and Doppler frequencies, and selecting the estimated angle of arrival using matching metrics derived from the Doppler frequencies and candidate angles, while also estimating velocity vectors to resolve ambiguity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wide aperture radar with increased receiver spacing is used, then angular resolution and field of view are improved, but angle of arrival ambiguity occurs due to phase differences exceeding π

Engineering Contradiction:

Improveangular resolutionVSAvoidangle measurement accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent combines phase difference information from multiple receivers with Doppler frequency measurements to resolve angle of arrival ambiguity. By merging these two types of measurements, the system maintains the wide aperture configuration for high angular resolution while eliminating the reliability issue of ambiguous angle measurements through the additional Doppler information.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Doppler frequency measurements serve as an intermediary to resolve the ambiguity between multiple candidate angles. The Doppler information acts as a mediator that provides additional constraints to distinguish the correct angle of arrival from the ambiguous candidates generated by the wide aperture phase difference measurements.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If receiver spacing is increased beyond half wavelength, then field of view expands, but phase differences exceed π causing measurement ambiguity

Engineering Contradiction:

Improvefield of viewVSAvoidangle measurement reliability

Core Design Contradiction:

Area of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The patent merges phase difference measurements from the wide-spaced receivers with Doppler frequency measurements to resolve angle ambiguity. This combination allows the system to maintain the expanded field of view provided by wide receiver spacing while eliminating measurement reliability issues through the complementary Doppler information.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the measurement parameters by introducing Doppler frequency measurements in addition to phase difference measurements. This parameter change provides new information that resolves the ambiguity caused by large receiver spacing, allowing the system to maintain both wide field of view and reliable angle measurements.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple candidate angles are generated from phase differences, then angular resolution is maintained, but selection of the correct angle becomes ambiguous

Engineering Contradiction:

Improveangular resolutionVSAvoidangle identification accuracy

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Doppler frequency measurements serve as an intermediary to resolve the ambiguity between multiple candidate angles. The Doppler information provides additional constraints that eliminate incorrect angle candidates, preventing loss of angle identification accuracy while maintaining the high angular resolution provided by multiple candidates.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses Doppler frequency information as feedback to validate and select the correct angle of arrival from multiple candidates. The Doppler measurements provide feedback that confirms which candidate angle is correct, preventing angle identification errors while maintaining the benefits of multiple angle hypotheses for high resolution.

Inventive Principle:

Principle #23Feedback

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 effectively resolves angle of arrival ambiguity in wide aperture radar systems by using Doppler measurements to distinguish between multiple angle hypotheses, improving angular resolution and target detection accuracy.

Implementation Method 1

determining Doppler frequencies fdi based on the received reflections

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS10690743B2Doppler measurements to resolve angle of arrival ambiguity of wide aperture radar

Publication Date: 2020.06.23 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system and method to resolve angle of arrival (AOA) ambiguity in a radar system include receiving received reflections at a plurality of transceiver nodes. Each transceiver node among the plurality of transceiver nodes of the radar system receives one or more of the received reflections at respective one or more receive elements. The method includes determining candidate AOAs {circumflex over (θ)}i based on phases differences in the received reflections at the plurality of transceiver nodes, and determining Doppler frequencies fdi based on the received reflections. An estimated AOA {circumflex over (θ)} is selected from among the candidate AOAs {circumflex over (θ)}i based on matching metrics μi between the Doppler frequencies and the candidate AOAs {circumflex over (θ)}i.