Radar Warning Receiver AOA Stabilization via 3D Kalman Tracking

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Solution Overview

Problem

Conventional airborne radar warning receiver systems face inaccuracies in determining the angle of arrival (AOA) of radar signals due to antenna gain irregularities and multipath effects caused by aircraft reflections and shadowing, which are not effectively addressed by existing stabilization methods that rely on two-dimensional processing.

Innovation Solution

The system employs a three-dimensional tracking method using a Kalman filter or similar techniques, combining antenna signals with inertial navigation data to stabilize and refine AOA calculations, converting measurements into stable inertial coordinates for improved accuracy and tracking, even in the absence of direct signal measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional two-dimensional stabilization methods are used, then the system is simple to implement, but AOA determination accuracy deteriorates due to antenna gain irregularities and multipath effects

Engineering Contradiction:
ImproveAOA determination accuracyVSAvoidstabilization processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from two-dimensional AOA stabilization to three-dimensional tracking by incorporating range dimension. The system uses 3D track coordinates (azimuth, elevation, range) instead of merely 2D AOA angles, allowing stabilization in a volumetric space that better represents the physical environment and reduces the impact of localized 2D anomalies.

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

Solution Approach 2:

The patent introduces an intermediary 3D track file as a mediator between raw AOA measurements and final stabilized output. This track file accumulates and processes measurements over time, using intermediate calculations involving range and spatial coordinates to produce more accurate stabilized AOA values than direct 2D processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If three-dimensional tracking with Kalman filter is implemented, then AOA determination accuracy is improved, but computational complexity increases

Engineering Contradiction:
ImproveAOA determination accuracyVSAvoidcomputational processing power
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent performs preliminary calculations of 3D track coordinates and range estimates before final AOA stabilization. By pre-computing intermediate values such as track-to-origin vectors and spatial relationships, the system reduces the computational burden of the Kalman filter updates while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements partial 3D tracking by focusing computational resources on the most critical dimensions for AOA stabilization. Rather than fully processing all possible 3D parameters with equal detail, the system applies selective processing to azimuth and elevation while using range as a supporting dimension, optimizing the balance between accuracy and computational load.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3123197B1Methods and apparatus for determining angle of arrival (AOA) in a radar warning receiver
Publication Date: 2018.05.02 RAYTHEON CO
  • EP3123197B1 patent drawingFigure 1
  • EP3123197B1 patent drawingFigure 2
  • EP3123197B1 patent drawingFigure 3

AI summary

Methods and apparatus for determining an angle of arrival in a radar warning system that uses tracking to provide a more accurate angle of arrival than conventional systems. In exemplary embodiments, angle of arrival and range are mapped from measured body angles to a 3D coordinate system where modern tracking techniques are applied to improve accuracy and stabilization of measurements, then mapped back into body angles for display.