Adaptive Clutter Rejection in Phased Array Beam Patterns
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Solution Overview
Problem
Phased array radar systems face challenges in generating a Cosecant-squared antenna pattern with low side lobes due to module failures and auxiliary blockages, which degrades clutter rejection and signal-to-noise ratio.
Innovation Solution
An adaptive processing method that determines element weightings to generate a desired antenna beam pattern with low side lobes by approximating amplitude weights from an ideal linear array pattern and performing phase-only pattern synthesis, enabling selective module operation to achieve a Cosecant-squared pattern with −50 db side lobes in a two-dimensional array with arbitrary profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If module failures and auxiliary blockages are present in the phased array, then the system complexity increases, but the antenna pattern quality deteriorates with high side lobes
Solution Approach 1:
The patent implements dynamic adaptation by continuously monitoring the operational status of array elements and automatically recalculating excitation weights to compensate for failures and blockages. The system transitions from a static predetermined pattern to a dynamic adaptive pattern that maintains low side lobes despite changing array configurations.
Solution Approach 2:
The patent changes the excitation parameters (amplitude and phase weights) of remaining operational elements to compensate for failed elements and blockages. By adjusting these parameters through iterative optimization, the system maintains the desired Cosecant-squared pattern with low side lobes despite physical array deficiencies.
2Object-affected harmful factors
If traditional amplitude and phase control is used in the presence of failures, then the control complexity increases, but the clutter rejection performance deteriorates
Solution Approach 1:
The patent extracts the amplitude control function from the active element list by setting amplitude weights to zero for failed elements, effectively removing them from the radiation pattern generation. This simplifies the control approach by focusing phase adjustment only on operational elements while automatically excluding failed ones.
Solution Approach 2:
The patent implements an iterative feedback optimization process where the calculated antenna pattern is compared against the desired Cosecant-squared pattern, and excitation weights are adjusted in subsequent iterations to minimize side lobe levels and improve clutter rejection performance.
3Reliability
If a Cosecant-squared pattern is generated with failed elements, then the number of operational modules decreases, but the side lobe level increases
Solution Approach 1:
The patent applies local quality adjustment by assigning different excitation weights to different operational elements based on their positions and the desired pattern requirements. Elements near failed positions receive adjusted weights to compensate for the missing radiation, maintaining low side lobes locally while preserving overall pattern shape.
Solution Approach 2:
The patent performs preliminary identification and classification of failed elements before pattern synthesis, allowing the optimization algorithm to pre-adjust excitation weights of operational elements to compensate for anticipated gaps in the array configuration.
Data Source
AI summary
An adaptive processing method of and system for clutter rejection in a phased array beam pattern. The amplitude distribution of the transmit elements of a two-dimensional phased array is determined. A desired pattern with low side lobes for a linear array is synthesized. The amplitude distribution of the transmit elements of the two-dimensional phased array is compared with the synthesized pattern. Select elements of the two-dimensional array are disabled to best fit the determined amplitude distribution of the transmit elements of the two-dimensional phased array to the synthesized beam pattern. Phase only pattern synthesis is performed to produce a desired two-dimensional beam pattern with low side lobes to minimize any best fit errors.