Radio Emitter Localization Using Directional TOA Correlation
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Solution Overview
Problem
Existing methods for detecting unauthorized radio transmitting devices, such as drones, are ineffective due to their reliance on prior knowledge of the device and are difficult to differentiate from birds using traditional radar, especially when made from low-density materials.
Innovation Solution
A method using three or more sensors with directional and omnidirectional antennas to calculate the time-of-arrival of radio signals, applying correlation-based location finding and cluster filters to determine the radio emission source's location without prior knowledge of transmission frequencies, utilizing convex and elliptical/spherical boundaries to refine estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional radar methods are used to detect drones, then detection capability is limited, but the system cannot differentiate drones from birds effectively
Solution Approach 1:
The patent replaces traditional radar (mechanical/electromagnetic reflection-based system) with a radio signal emission detection system. Instead of detecting reflected radio waves from drone surfaces, the system detects radio signals actively emitted by drones for control and telemetry, fundamentally changing the detection mechanism to overcome the inability to differentiate drones from birds.
Solution Approach 2:
The patent introduces radio signal emission as an intermediary characteristic for detection. Rather than directly detecting physical presence through radar reflection, the system uses the intermediary of radio signal transmission (control signals, telemetry data) to identify drones, providing a reliable differentiation method since birds do not emit such signals.
2Reliability
If narrow range radio spectrum monitoring is used for drone detection, then known drones can be detected, but the system requires prior knowledge of signal patterns
Solution Approach 1:
The patent implements a universal detection system that monitors broad radio spectrum ranges rather than narrow, drone-specific frequencies. The system can detect and analyze radio signals from any radio-emitting device regardless of specific frequency or protocol, eliminating the need for pre-programmed signal pattern libraries for different drone types while maintaining high detection reliability.
Solution Approach 2:
The patent changes the detection parameter from specific frequency-range matching to broad spectrum analysis with signal characteristic identification. Instead of fixing detection to known drone frequencies and patterns, the system analyzes radio signals across wide frequency ranges and identifies drones based on transmission characteristics, enabling detection of unknown or modified drone signals without requiring updates to a signal library.
3Measurement precision
If correlation-based time-of-arrival location finding is used, then accurate location can be determined, but the system requires three or more sensors with complex coordination
Solution Approach 1:
The patent segments the location finding function across multiple independent sensors distributed in space. Each sensor independently detects radio signal arrival time and transmits this data to a central processing system. This segmentation allows the system to achieve accurate 3D location through time-difference-of-arrival calculations while maintaining operational simplicity at each sensor node, as each sensor only needs basic timing capability rather than complex coordination functions.
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 accurate detection and location of radio emission sources, including drones, within and outside a convex hull defined by sensor locations, enhancing security and safety by providing precise tracking and countermeasure deployment.
Implementation Method 1
Time-of-arrival methods, based on differences in transit time between an actively emitting object and a number of sensors
Implementation Method 2
carrying out a correlation based time-of-arrival location finding calculation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A method of detecting a radio emission source (2) includes receiving three or more radio signal datasets from three or more respective sensors (3). Each sensor corresponds to a physical location and includes at least one radio receiver. The three or more radio signal datasets include one or more directional datasets obtained using a directional antenna or a directional antenna array of the corresponding sensor, and two or more omnidirectional datasets, each obtained using an omnidirectional antenna or an omnidirectional antenna array of the corresponding sensor. The method also includes determining whether an emitter signal (8) within a target frequency range is present in any of the one or more directional datasets. The method also includes, for each directional dataset, in response to the emitter signal is present in that directional dataset, carrying out a correlation based time-of-arrival location finding calculation based on that directional dataset and at least two further radio signal datasets.