RF Emitter Geo-location via Gain Projection MLS
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Solution Overview
Problem
Existing systems for locating radio frequency (RF) emitters require complex and expensive phase coherent receivers, making them costly and resource-intensive for use in determining the geographic location of RF emitters from a single moving platform.
Innovation Solution
The method employs a beamforming antenna array with multiple overlapping beams, synchronized receivers to measure time-of-arrival and amplitude, and a processor to form a Maximum Likelihood Surface (MLS) by projecting beamformed antenna gain patterns onto the underlying terrain, estimating the emitter's location without the need for phase coherent receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interferometer-based geo-location techniques using multiple phase coherent receivers are employed, then the location of RF emitters can be determined, but the system becomes complex and expensive
Solution Approach 1:
The patent replaces expensive phase coherent receivers with inexpensive amplitude-only receivers. The system uses multiple low-cost receivers that measure only signal amplitude and time of arrival, eliminating the need for complex phase measurement hardware while still achieving accurate emitter location through statistical processing of amplitude data from multiple receivers
Solution Approach 2:
The patent changes the measurement parameter from phase (which requires complex coherent receivers) to amplitude (which can be measured with simple receivers). By using amplitude measurements combined with time of arrival data from multiple receivers, the system achieves location determination without requiring phase coherent hardware
2Measurement precision
If interferometer-based techniques with phase coherent receivers are used, then emitter location can be determined, but the cost and resource requirements increase
Solution Approach 1:
The patent employs multiple inexpensive amplitude-only receivers instead of expensive phase coherent receivers. The receivers are simpler, cheaper devices that measure only signal amplitude and arrival time, and the system achieves accurate location determination through statistical processing of data from multiple such receivers
Solution Approach 2:
The patent uses multiple copies of simple amplitude-only receivers distributed in space rather than a single complex phase coherent receiver. By deploying multiple identical, inexpensive receivers and processing their combined measurements, the system achieves the same location determination capability as interferometer systems but at lower cost
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
This approach allows for accurate geo-location of RF emitters at a lower cost and with reduced processing resources, minimizing side-lobe influence and achieving improved accuracy by focusing on main-lobe detections, thus reducing the Area Error Probability.
Implementation Method 1
spatially filtering and receiving RF signals through use of a beamforming antenna array having multiple overlapping beams
Implementation Method 2
detecting and measuring the time-of-arrival and amplitude of signals which are received in each beam
Data Source
AI summary
A system and method for estimating the geographic location of an RF emitter which involves spatially filtering and receiving RF signals through use of a beamforming antenna array having multiple overlapping beams; detecting and measuring the time-of-arrival and amplitude of signals which are received in each beam through use of multiple synchronized receivers; identifying simultaneous detections of the same emitter which have occurred in adjacent beams; projecting the associated beamformed antenna gain patterns onto the underlying terrain for all instances in which there was a simultaneous detection in adjacent beams; weighting and accumulating all projections to form a Maximum Likelihood Surface (MLS); and finally, estimating the location of the emitter through analysis of the resulting MLS.