Adaptive Array Perturbational Processing for Direction Finding
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Solution Overview
Problem
Existing adaptive array antenna systems lack cost-effective and size-efficient solutions for signal source location and direction finding, particularly in applications with constraints on space, weight, cost, power, and computational capacity, and fail to provide viable methods for estimating the correlation matrix necessary for direction finding.
Innovation Solution
A correlation matrix estimation system using sequences of perturbation signals, including odd and even symmetry sequences, to modify and process received signals, enabling the derivation of a correlation matrix for direction finding purposes, even without access to individual antenna element signals, through a beamformer and weighting signal units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If parallel processing of individual antenna element signals is used for direction finding, then direction finding capability is achieved, but hardware complexity and computational capacity requirements increase significantly
Solution Approach 1:
The patent extracts only the necessary information for direction finding by using a single antenna output signal combined with perturbation sequences, rather than processing all individual element signals. This extraction approach obtains the correlation matrix elements needed for MUSIC algorithm while avoiding the complexity of parallel processing all antenna element signals.
Solution Approach 2:
The patent introduces perturbation sequences as an intermediary tool to enable correlation matrix estimation from a single antenna output. These known sequences are injected into the system and their effects are measured through the adaptive processor, allowing indirect extraction of correlation information without direct access to individual element signals.
2Object-affected harmful factors
If adaptive processing is implemented to reduce jamming effects, then anti-jam capability is improved, but the ability to determine jammer direction is lost
Solution Approach 1:
The patent performs preliminary action by injecting perturbation sequences into the adaptive processing system before actual signal processing occurs. This allows the system to pre-characterize its response and extract correlation matrix information that will be useful for subsequent direction finding operations without interfering with the adaptive jamming rejection function.
Solution Approach 2:
The patent implements feedback by using the known perturbation sequences as a reference to measure and extract correlation information from the adaptive processor output. The measured responses to the perturbation sequences are fed back to construct the correlation matrix, enabling direction finding while maintaining adaptive processing capabilities.
3Volume of moving object
If compact array configurations are used to meet size constraints, then space and weight are reduced, but computational capacity requirements increase
Solution Approach 1:
The patent extracts the essential correlation matrix information needed for direction finding from a single antenna output signal, avoiding the need to process and compute from all individual element signals. This extraction method reduces computational requirements while maintaining direction finding accuracy in compact array configurations.
Solution Approach 2:
The patent creates a simplified representation of the correlation matrix by measuring the system's response to known perturbation sequences. This copying approach reconstructs the necessary correlation information from indirect measurements rather than direct signal processing, reducing computational burden in compact arrays.
Data Source
AI summary
Prior adaptive antenna systems can reduce effects of a jamming or interfering signal by reducing antenna gain in the direction of such signal. However, direction finding capability to enable location of the source of such signal in order to permit corrective or other action has not been available on an economical, low computational basis. Described systems and methods provide correlation matrix estimation to enable direction finding. In an embodiment, a beamformer unit derives an adaptive output signal with use of odd symmetry sequence perturbation signals and weighting signals developed with use of odd symmetry sequence perturbation signals. An extractor unit utilizes even symmetry sequence perturbation signals to process a form of the adaptive output signal, in derivation of output signals representative of a correlation matrix usable for direction finding. The even symmetry sequence signals are thus used to process an adaptive output signal which includes even symmetry sequence values as a result of derivation of the adaptive output signal with interaction between components of odd symmetry sequence perturbation signals.