Antenna Array Signal Detection via 2D Fourier Transform
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Solution Overview
Problem
Existing surveillance systems face difficulties in detecting weak signals and distinguishing between signals of identical frequency originating from different directions, limiting the maximum detection distance and accuracy.
Innovation Solution
A method and system using an array of antenna elements that perform a two-dimensional Fourier transform on sampled signals to determine the frequency and azimuth angle of electromagnetic radiation sources, capable of detecting signals over a wide angle of view and distinguishing between sources with identical frequencies by calculating a two-dimensional Fourier transform and identifying peaks in the frequency-azimuth plot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection systems are used, then the system structure is simple, but the detection distance is limited and weak signals cannot be detected
Solution Approach 1:
The patent applies two-dimensional Fourier transform to convert the signal processing from one dimension to two dimensions, creating a frequency-azimuth plot that enables simultaneous resolution of frequency and directional information. This dimensional transformation allows the system to distinguish between signals of identical frequency from different directions and extend detection capability to weak signals without requiring complex additional hardware.
2Measurement precision
If conventional signal processing is used, then the processing is simple, but signals from different directions with identical frequency cannot be distinguished
Solution Approach 1:
The patent introduces a second dimension to signal processing by computing the two-dimensional Fourier transform, which maps signals onto a frequency-azimuth plot. This creates a new dimensional space where signals are separated not only by frequency but also by azimuth angle, enabling the system to distinguish between multiple sources with identical frequencies from different directions through peak identification in the transformed domain.
3Measurement precision
If the antenna array is tuned for narrow frequency band, then the frequency selectivity is improved, but the ability to detect signals over wide angle of view is reduced
Solution Approach 1:
The patent designs the antenna array to be tuned across a wide frequency band, enabling the system to detect signals from multiple frequency sources simultaneously. The two-dimensional Fourier transform processing then provides frequency selectivity by identifying peaks in the frequency-azimuth plot, allowing the system to achieve both wide angle of view coverage and accurate frequency detection without requiring multiple separate antenna arrays tuned to different frequency bands.
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
Enables the detection of weak signals and accurate determination of frequency and azimuth angle, even when the number of sources, frequencies, or directions are unknown, with enhanced sensitivity and ability to differentiate between signals spatially separated sources with the same frequency.
Implementation Method 1
Signal sources in the surveillance space radiate electromagnetic (EM) signals towards the receiving antenna array which collects the radiated signals
Implementation Method 2
The azimuth determination processing involves calculating a two dimensional Fourier transform of the input array
Data Source
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AI summary
A respective electromagnetic parameter and spatial disposition of an unknown number of signal sources in a surveillance space simultaneously bombarded by multiple signals are determined by receiving multiple signals at each of a plurality of widebeam, wideband antennas equally spaced apart in a linear array. Respective antenna signals are simultaneously sampled to generate a two-dimensional array of values. A two- dimensional Fourier transform is computed whose peaks satisfy one or more predetermined criteria, each peak being indicative of a signal source in the surveillance space, whereby the location of the peak in the Fourier transform Fjk indicates the frequency and the azimuth of the respective signal source and the amplitude of the peak indicates the amplitude of the signal source. When implemented using two mutually perpendicular arrays of receiving antennas, an additional Fourier transform of the two- dimensional Fourier transform generates, for each identified emitter, independent azimuth and elevation angles.