Beamsteerer Using Narrow Nulls for Reflection Rejection

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Solution Overview

Problem

Existing sound localization systems face challenges in achieving high precision and accuracy due to difficulties in creating narrow beam angles and discriminating between direct and reflected sound sources, often requiring expensive solutions and being prone to errors from side lobes and phase/amplitude errors.

Innovation Solution

A beamsteerer system using a compact array of sensors with optimal geometry to generate specific 3D beam patterns with deep nulls, allowing for accurate detection of sound sources while rejecting reflections, achieved through a unique array design and algorithm that creates multiple look directions with constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a simple beamformer is used for source localization, then the system is easy to implement, but it produces multiple side lobes and limited beam width that prevent efficient discrimination of side reflections

Engineering Contradiction:

Improveease of implementationVSAvoidsource localization precision

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

Instead of trying to create a narrow main beam to locate sources, the patent inverts the approach by creating a narrow null (minimum) in the beam pattern at the location of unwanted reflections. This null-steering technique suppresses side reflections while maintaining a broader main beam, thereby achieving reflection discrimination without requiring expensive highly directional beamformers

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of side lobes in simple beamformers into a beneficial feature by deliberately placing narrow nulls at the angular positions of side reflections. The side lobes that would normally cause erroneous detections are now suppressed at specific angles where reflections are expected, turning a weakness into a strength for reflection rejection

Inventive Principle:

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

2Measurement precision

If highly directional beam patterns are used to achieve high resolution, then angular resolution is improved, but significant side lobes are created that lead to erroneous look directions

Engineering Contradiction:

Improveangular resolutionVSAvoiddetection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the conventional beamforming approach by focusing energy suppression (creating narrow nulls) rather than energy concentration (creating narrow main beams). This allows achieving high angular resolution for reflection rejection without the harmful side lobes that plague highly directional beamformers

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies local quality by creating highly directional nulls only in specific angular directions where side reflections are expected, while maintaining a broader main beam pattern for overall source detection. This localized suppression achieves high resolution where needed without creating system-wide side lobe problems

Inventive Principle:

Principle #3Local quality

3Measurement precision

If sensors are spaced apart by significant distance to obtain reasonable time delay, then TDOA measurement is improved, but the device size increases to 0.8×0.8 m

Engineering Contradiction:

ImproveTDOA measurement precisionVSAvoiddevice size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent transitions from 2D planar sensor arrays (which require large spacing for adequate TDOA) to 3D spherical or tetrahedral sensor configurations. This dimensional change allows achieving the same angular resolution and reflection rejection capability with significantly reduced sensor spacing and overall device volume

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the geometric parameters of the sensor array from large-scale 2D configurations to compact 3D configurations. By optimizing the 3D spatial arrangement and using narrow null beamforming techniques, the system achieves equivalent or superior performance with reduced sensor spacing and smaller overall device footprint

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

The system provides high angular resolution and robust error tolerance, enabling precise detection of sound sources with a narrow null and rejecting side reflections, even in the presence of phase and amplitude errors.

Implementation Method 1

the array information is used to synthesize a beam that is aimed at various points in a domain of interest

Methodology Applied

Scientific EffectBeamforming:

Implementation Method 2

a beamsteerer for steering a narrow null toward a domain of interest

Methodology Applied

Scientific EffectNull steering:

Data Source

PatentUS7792313B2High precision beamsteerer based on fixed beamforming approach beampatterns

Publication Date: 2010.09.07 MITEL CORP

AI summary

A beamsteerer for broadband energy source location, comprising an array of sensors, each for generating a signal vector within one of a plurality of sectors in a domain of interest, and a beamformer for receiving and multiplying each signal vector by a set of optimal weight vectors to generate a plurality of beampatterns, each of the beampatterns being characterized by a null having high angular resolution, and detecting the source by selecting a maximum steering index.