Passive RF Source Geolocation via Cross-Correlation
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Solution Overview
Problem
Current methods for geolocating radio frequency (RF) sources often require active transmission of signals, which can be hazardous or undesirable in certain applications, such as military scenarios, and lack the capability to identify multiple RF sources passively.
Innovation Solution
A passive system utilizing multiple antennas at a single or nearby location to receive RF signals, processing cross-correlations between signals from different antenna pairs to estimate the location of RF sources without emitting signals, allowing for the identification of multiple sources using cross-correlation techniques and hyperbola projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radar systems transmit signals to identify RF sources, then range and distance can be determined, but safety hazards increase and location concealment is lost
Solution Approach 1:
Instead of actively transmitting signals to locate RF sources (radar approach), the system passively receives RF signals and uses cross-correlation techniques to determine source locations. This inversion of the active/passive role eliminates the hazard of signal transmission while maintaining location identification capability through mathematical signal processing of received signals.
Solution Approach 2:
The patent replaces the mechanical signal transmission and reflection system (radar) with an electronic signal processing system that uses cross-correlation of received signals to determine location. This substitution eliminates the need for active transmission while achieving the same measurement objective through computational methods applied to passive signal reception.
2Object-affected harmful factors
If passive systems with single sensor location are used, then safety is improved, but capability to identify multiple RF sources is limited
Solution Approach 1:
The system divides the sensor array into multiple antenna elements that can independently receive signals. By processing cross-correlations between different antenna pairs, the system segments the detection task to identify multiple RF sources simultaneously. Each antenna pair contributes to the overall capability of resolving multiple sources through their respective signal characteristics.
Solution Approach 2:
The patent transitions from single-point sensor measurement to multi-dimensional signal space analysis by computing cross-correlations between multiple antenna pairs. This dimensional expansion in the signal processing domain enables the system to resolve multiple RF sources based on their distinct signal patterns and spatial relationships, even though the physical sensor location remains fixed.
3Measurement precision
If multiple antenna pairs are used for cross-correlation processing, then location estimation accuracy improves, but device complexity increases
Solution Approach 1:
The patent designs the sensor system so that multiple antenna pairs serve multiple functions: each pair provides cross-correlation data for location estimation, and collectively they enable identification of multiple RF sources. The same physical infrastructure (antenna array) performs both single-source and multi-source detection tasks, eliminating the need for separate systems for different detection objectives.
Data Source
AI summary
A sensor system may be configured to identify a location of a radio frequency (RF) source using an angle of arrival estimation technique. A sensor system may identify a candidate location of an RF source using hyperbola positioning techniques with two or more antennas at a similar geolocation with reference to the RF source. The sensor system may additionally be able to identify a plurality of RF sources using two or more antennas at a similar geolocation.