Grating Lobe Mitigation in Array Radar Antennas
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Solution Overview
Problem
Current methods for distinguishing mainlobe detections from grating lobe and sidelobe detections in radar signal processing often require additional antenna and receiver architecture, and residual grating lobes and sidelobes can result in false hits, necessitating improved techniques to differentiate between these signals.
Innovation Solution
The method involves applying receive weights and subarray weights to steer subarrays in array radar antennas, generating scaled subarray beam data, and using guard beam data to digitally distinguish between mainlobe, grating lobe, and sidelobe detections by comparing the magnitude of return radar data against guard beam data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If simultaneous receive beams are generated using multiple subarrays with large subarray spacings, then wide area scanning capability is improved, but grating lobes are generated that cause false target detections
Solution Approach 1:
The antenna array is divided into multiple subarrays, each capable of independent beamforming. By segmenting the array and applying different receive weights to each subarray, the system can generate simultaneous receive beams while maintaining control over grating lobe directions through digital beam steering of individual subarrays
Solution Approach 2:
The patent applies receive weights and subarray weights as adjustable parameters to steer subarrays to different directions. By dynamically changing these weight parameters, the system can steer subarrays away from grating lobe directions while maintaining mainlobe sensitivity, thus reducing false detections without altering the physical array structure
2Object-generated harmful factors
If antenna architecture is modified to reduce grating lobe size, then false detection rate is reduced, but system complexity and hardware requirements increase
Solution Approach 1:
The patent replaces physical antenna architecture modifications with digital signal processing methods. Instead of changing the mechanical arrangement of antenna elements or adding guard horns, the system uses digital receive weights, subarray weights, and beam pattern scaling to achieve grating lobe mitigation, thereby reducing hardware complexity while maintaining effectiveness
3Measurement precision
If post-processing digital filtering is applied to distinguish mainlobe from grating lobe detections, then detection accuracy is improved, but processing time and computational complexity increase
Solution Approach 1:
The patent performs preliminary beamforming and grating lobe mitigation during the signal reception and initial processing stages. By pre-steering subarrays away from grating lobe directions and applying scale factors based on beam patterns before target detection, the system reduces the need for extensive post-processing filtering, thus improving detection accuracy while minimizing additional processing time
Data Source
AI summary
A method that digitally distinguishes mainlobe detections from grating lobe and sidelobe detections without need for added antenna or receiver architecture. The method includes applying receive weights to return radar data for each radar receive element to steer each subarray of a array radar antenna to a direction other than the subarray transmit angle and includes applying a subarray weight to each subarray to generate the array radar antenna receive beam data having magnitude and phase components. The method includes applying predetermined scale factors to the subarray beam data magnitude for each subarray to generate scaled subarray beam data magnitudes. The method includes generating guard beam data for each subarray based on the scaled subarray beam data magnitudes. The method also includes determining if the return radar data corresponds to a mainlobe or a grating lobe or sidelobe based on the receive beam data and the guard beam data.