Direction Finding Using Wideband Power Spectrum Analysis
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Solution Overview
Problem
Existing direction finding systems face challenges in accurately determining the incident angle of RF signals, especially for short-lived or fast-moving signals, due to their reliance on single-frequency channels and voltage amplitudes, which limits their ability to track multiple signal sources simultaneously.
Innovation Solution
A method and apparatus that utilize an antenna array to generate direction finding signals based on measured power values across a wide bandwidth, allowing for the calculation of incident signal angles at multiple frequencies from a single set of measurements, using power spectrum measurements and antenna gain patterns to determine signal angles quickly and robustly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single receiver DF system is used, then device complexity is reduced, but the ability to detect and track short-lived or fast-moving signals deteriorates due to the need for rotation
Solution Approach 1:
The system divides the signal reception function across multiple receivers (antenna elements) arranged in an array, eliminating the need for a single receiver to rotate. Each receiver element simultaneously captures signals from different directions, enabling rapid detection of fast-moving signals while maintaining relatively simple individual receiver designs.
Solution Approach 2:
The system transitions from a single-point reception model to a spatial array model, adding dimensional distribution to the receiver configuration. By arranging multiple receivers in specific geometric patterns, the system achieves directional information without mechanical rotation, improving signal detection speed for moving targets.
2Measurement precision
If voltage amplitude measurements are used for direction finding, then measurement precision may be maintained, but the ability to track multiple signal sources simultaneously deteriorates due to single-frequency channel limitations
Solution Approach 1:
The system employs power spectrum measurements that can simultaneously process multiple frequency components and multiple signal sources. The power measurement approach is universally applicable across different frequencies and signal types, enabling the system to track multiple signal sources simultaneously while maintaining incident angle measurement precision through spectral analysis.
Solution Approach 2:
The system changes the measurement parameter from voltage amplitude to signal power, and from single-frequency to wideband spectrum measurements. This parameter transformation enables simultaneous processing of multiple frequency components and multiple signal sources, greatly enhancing multi-signal tracking capability while preserving direction-finding accuracy through spectral power distribution analysis.
3Device complexity
If single-frequency channels are used, then measurement simplicity is maintained, but productivity deteriorates due to inability to track multiple signal sources
Solution Approach 1:
The system transforms the measurement approach from single-frequency voltage amplitude to wideband power spectrum measurements. This parameter change enables simultaneous analysis of multiple frequency components, dramatically increasing signal tracking throughput and productivity while maintaining relatively simple measurement system architecture through direct power spectral estimation.
Data Source
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AI summary
A method of determining incident angles of Radio Frequency, RF, signals received by an antenna array comprising a plurality of antennae is described. The method comprises generating a plurality of direction finding, DF, signals based on antenna signals received from the antenna array, wherein each DF signal corresponds to a respective antenna array element and each antenna array element corresponds to one or more antennae. A plurality of DF spectra are then generated, each DF spectrum corresponding to a respective DF signal and comprising measured values of signal power at two or more given respective frequencies. An incident signal angle is calculated for each given frequency, based on the measured values of power at the frequency, the configuration of the antennae in the antenna array and antenna gain patterns corresponding to the antenna array elements.