Hybrid Drone Geolocation Using Signal Analysis

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Solution Overview

Problem

Current geolocation techniques using drones to determine the position of a ground-based transmitter are not satisfactory as they require wide-band signal transmission for TDOA and long-duration emission for FDOA, and combining these techniques does not fully address the precision and observability issues.

Innovation Solution

A method employing two drones with communication modules that analyze power, time, and frequency differences of radio signals, along with direction measurements, to determine the transmitter's position using a hybrid location process that combines PDOA, TDOA, FDOA, and triangulation techniques, allowing for precise geolocation independent of signal type.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If TDOA technique is used for geolocation, then the position of the transmitter can be determined using time difference of arrival, but the transmitter must transmit in a wide band which increases signal complexity and transmission requirements

Engineering Contradiction:
Improvegeolocation precisionVSAvoidsignal type compatibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent combines multiple geolocation techniques (TDOA, FDOA, and amplitude-based methods) into a unified hybrid system that processes different signal characteristics simultaneously. This merging allows the system to achieve precise geolocation without requiring wide-band transmission, as each technique contributes different aspects of signal analysis that together provide accurate positioning regardless of signal type.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The geolocation system is designed to perform multiple functions by analyzing different signal properties (time of arrival, frequency difference, and amplitude) from the same transmitter signals. This multi-functional approach enables the system to work with various signal types without requiring specialized wide-band transmission, thereby improving adaptability while maintaining precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If FDOA technique is used for geolocation, then the position can be determined using frequency difference of arrival, but a long-duration emission is required which increases observation time

Engineering Contradiction:
Improvegeolocation precisionVSAvoidobservation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges FDOA with TDOA and amplitude-based geolocation methods to create a hybrid system where multiple measurement types are processed simultaneously. This combination allows the system to achieve accurate geolocation without requiring the long observation periods needed for pure FDOA, as the additional measurement dimensions provide complementary information that accelerates the geolocation process.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If existing geolocation techniques are combined, then more signal characteristics can be analyzed, but the system complexity increases and does not fully resolve precision and observability issues

Engineering Contradiction:
Improvegeolocation precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the geolocation system into distinct functional modules: a signal reception module that collects signals from multiple drones, a signal processing module that separately analyzes time of arrival, frequency difference, and amplitude characteristics, and a position calculation module that integrates these measurements. This segmentation manages system complexity by organizing the combined techniques into manageable, independent processing stages that can be implemented and optimized separately.

Inventive Principle:
Principle #1Segmentation

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 method provides precise and reliable geolocation of transmitters by combining multiple signal analysis techniques, improving upon existing methods by enabling accurate positioning regardless of signal type and reducing the requirements for wide-band transmission or long-duration emission.

Implementation Method 1

Each communication module 12, 14 is able to receive radio signals from the transmitter 11

Methodology Applied
Scientific EffectRadio signal detection: Electromagnetic Induction

Data Source

PatentEP3557278B1Method for geolocation of a transmitter, associated geolocation system and computer program product
Publication Date: 2021.10.13 THALES SA
  • EP3557278B1 patent drawingFigure 1~2

AI summary

The present invention relates to a method for geolocating a radio signal transmitter using at least two drones. The method comprises the steps of taking (110, 120) a plurality of measurements by each of the drones in flight, analyzing (140) all the measurements taken and determining the relative position of the transmitter with respect to one of the drones, and determining (150) the absolute position of the transmitter as a function of said relative position and the absolute position of the corresponding drone. Each plurality of measurements includes measurements of received radio signal strengths and at least one type of measurement selected from a first group consisting of: measurements of direction of arrival, measurements of time of arrival, and measurements of frequencies.