AESA Radar Ground Mapping for Runway Imaging and Clutter Suppression

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Solution Overview

Problem

Traditional airborne weather radar systems face challenges in effectively suppressing ground clutter for predictive wind shear detection due to the limitations of mechanically driven slotted waveguide array antennas, which result in inadequate side lobe levels and reduced effective isotropic radiated power, especially when scanning off boresight.

Innovation Solution

A radar system incorporating an Active Electronically Scanned Array (AESA) and ground mapping linear arrays operating on a separate receive channel, sending I/Q digital terrain mapping data to a radar processing unit, which provides constant ground mapping and can be configured as a radar interferometer or near field probes for calibration, allowing for improved ground clutter suppression and high-resolution terrain mapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If uniform aperture illumination is used to maximize EIRP, then effective isotropic radiated power is improved, but side lobe levels deteriorate

Engineering Contradiction:

Improveeffective isotropic radiated powerVSAvoidside lobe levels

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent applies different illumination tapers to different functional regions of the AESA: uniform illumination for main beam transmission (maximizing EIRP) and tapered illumination for side lobe suppression (minimizing interference). This local differentiation resolves the contradiction between maximizing power and minimizing harmful side lobes.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically switches between different illumination patterns (uniform and tapered) based on operational requirements. During normal operation, uniform illumination maximizes EIRP; during ground clutter suppression modes, tapered illumination reduces side lobe levels. This dynamic adaptation resolves the static contradiction.

Inventive Principle:

Principle #15Dynamics

2Object-generated harmful factors

If slotted waveguide antenna arrays are used for ground clutter suppression, then ground return attenuation is improved, but radar range performance deteriorates

Engineering Contradiction:

Improveground return attenuationVSAvoidradar range performance

Core Design Contradiction:

Object-generated harmful factorsVSPower

Solution Approach 1:

The patent segments the antenna system into functionally distinct components: the AESA for primary weather detection and range performance, and separate ground mapping linear arrays for specialized ground clutter suppression. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ground mapping linear arrays act as intermediary elements that specifically target ground returns. These arrays receive separate channel signals and process ground clutter independently, mediating between the main AESA transmission and the ground interference, thereby suppressing ground returns while preserving main beam power for weather detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If AESA panels are arranged in chevron configuration, then scan coverage is improved, but side lobe levels worsen

Engineering Contradiction:

Improvescan coverageVSAvoidside lobe levels

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies localized side lobe cancellation techniques to specific regions affected by the chevron configuration. Rather than treating the entire array uniformly, different illumination patterns and cancellation algorithms are applied to different panel regions to compensate for the geometry-induced side lobe elevation while maintaining expanded scan coverage.

Inventive Principle:

Principle #3Local quality

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 configuration enhances ground clutter suppression and enables the creation of high-resolution ground maps, distinguishing between weather phenomena and ground targets, while maintaining effective isotropic radiated power and improving radar performance, especially at large scan angles off boresight.

Implementation Method 1

Traditional commercial airborne weather radar systems utilize a simple ground clutter suppression (GCS) algorithm for predictive wind shear (PWS) detection

Methodology Applied

Scientific EffectRadar: Radar

Implementation Method 2

Analog AESAs commonly transmit in uniform aperture illumination to maximize effective isotropic radiated power (EIRP)

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentUS20250012919A1Ground clutter suppression and runway imaging via radar ground mapping

Publication Date: 2025.01.09 ROCKWELL COLLINS INC

AI summary

A radar system includes an AESA and at least one ground mapping linear array that operate on a separate receive channel and send I/Q digital terrain mapping data to a radar processing unit. The linear arrays provide constant ground mapping. The AESA may have more than one panel. Panels may be arranged as a chevron with the linear arrays disposed at the periphery. The AESA and linear arrays may be configured as a radar interferometer for track location and/or geolocation. The linear arrays may be configured as near field probes for insitu calibration.