AESA Runway Imaging With Linear Arrays for Ground 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) with separate ground mapping linear arrays operating on a receive channel, sending I/Q digital terrain mapping data to a radar processing unit, providing constant ground mapping and capable of configuring as a radar interferometer or near field probes for calibration, to enhance ground clutter suppression and radar performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If uniform aperture illumination is used to maximize EIRP, then radar range and power on target are improved, but side lobe levels deteriorate to -13.5 dBp which is insufficient for ground clutter suppression
Solution Approach 1:
The patent applies non-uniform aperture illumination weighting (tapering) across the AESA elements, where elements at the edges of the aperture are assigned lower weights than central elements. This creates local quality variations in the illumination distribution, suppressing side lobes to achieve -60 dB ground clutter rejection while maintaining sufficient main beam power for wind shear detection.
Solution Approach 2:
The patent changes the illumination parameter from uniform to non-uniform (tapered) distribution across the antenna aperture. By adjusting the weighting parameters of individual array elements, the system transforms the radiation pattern to achieve the required -60 dB side lobe level for effective ground clutter suppression in predictive wind shear detection.
2Object-generated harmful factors
If slotted waveguide array antennas are used to achieve -60 dB side lobe levels, then ground clutter suppression is improved, but effective isotropic radiated power deteriorates due to mechanical limitations
Solution Approach 1:
The patent replaces the mechanically driven slotted waveguide array with an electronically controlled AESA system. This substitution eliminates mechanical limitations and enables dynamic electronic control of aperture illumination, allowing simultaneous achievement of high EIRP and -60 dB side lobe levels through programmable weighting schemes without mechanical complexity.
Solution Approach 2:
The patent introduces dynamic control of aperture illumination weights in the AESA system, allowing real-time adjustment of element weighting to optimize both main beam power and side lobe suppression. This dynamic capability enables adaptive ground clutter rejection while maintaining maximum effective isotropic radiated power for wind shear detection.
3Measurement precision
If AESA panels are arranged in chevron configuration with linear arrays at periphery, then ground mapping capability is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the AESA system: the chevron-configured panels with peripheral linear arrays simultaneously provide weather detection, ground clutter suppression, and digital terrain mapping. This multi-functionality reduces the need for separate dedicated mapping antennas, managing complexity through functional integration rather than adding independent subsystems.
Solution Approach 2:
The patent segments the AESA into functional modules: chevron-configured panels for primary weather detection and peripheral linear arrays for ground mapping and interferometry. This segmentation allows independent optimization of each subsystem while maintaining overall system integration, managing complexity through modular architecture.
Data Source
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AI summary
A radar system includes an AESA and at least one ground mapping linear array (818, 822) that operate on a separate receive channel and send I/Q digital terrain mapping data to a radar processing unit (108). The linear arrays provide constant ground mapping. The AESA may have more than one panel (814, 816). 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.