UAV Flight Detection via RF Backscatter and FMCW Radar

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Solution Overview

Problem

The increasing number of unmanned aerial vehicles (UAVs) in urban areas necessitates stricter regulation and monitoring of their flight movements to ensure only registered aircraft operate within controlled airspace, as previous regulations are inadequate for professional applications and large, heavy drones.

Innovation Solution

A toll system utilizing RF backscatter technology with detection modules and a control module to track and identify UAVs, reconstructing their flight paths through data transmission from multiple detection modules, and implementing a toll system for fee collection and traffic regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple detection modules are deployed to track UAV flight movements, then monitoring reliability is improved, but system complexity and infrastructure requirements worsen

Engineering Contradiction:
Improvemonitoring reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring system is divided into multiple independent detection modules distributed along the flight path. Each module independently queries and detects UAVs passing through its sector, allowing the system to achieve comprehensive coverage and high reliability without requiring a single complex centralized system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A transponder equipped with RF backscatter technology is introduced as an intermediary device on the UAV. This transponder passively responds to queries from detection modules, enabling reliable identification and tracking without requiring active transmission from the UAV, thus improving monitoring reliability while keeping the UAV system simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If RF backscatter technology is used for UAV identification, then energy consumption is reduced, but identification capability and reliability worsen

Engineering Contradiction:
Improveenergy consumptionVSAvoididentification capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The detection modules serve themselves by using the reflected RF signals from the UAV's transponder for both identification and basic measurement purposes. The RF backscatter transponder passively modulates the reflected signal to convey identification information, eliminating the need for active transmission while maintaining reliable identification capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system changes the parameters of the RF signal by using frequency modulation (FMCW) and analyzing the reflected signal's frequency characteristics. This allows the detection modules to extract identification information and distance data from the passive backscatter signal, achieving reliable identification with minimal energy consumption from the UAV side.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If FMCW radar is used for distance measurement, then measurement precision is improved, but energy consumption and device complexity worsen

Engineering Contradiction:
Improvedistance measurement precisionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system replaces active radar transmission with passive RF backscatter measurement. The FMCW radar is implemented in the ground-based detection modules rather than on the UAV, substituting a high-energy mechanical transmission system with a low-energy electromagnetic reflection-based measurement system while maintaining measurement precision through signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reliable monitoring and control of UAVs, ensuring compliance with prescribed flight routes and regulations, allowing for the registration of drones, and implementing a cost-effective toll system to manage drone traffic.

Implementation Method 1

the at least two detection modules each include an FMCW radar unit (interrogator), whereby the FMCW radar units perform a query using a frequency-modulated continuous wave signal (FMCW)

Methodology Applied
Scientific EffectFrequency-modulated continuous wave (FMCW):

Implementation Method 2

the transponder includes an RF back scatter transponder

Methodology Applied
Scientific EffectRF backscatter: Reflection

Data Source

PatentEP3604131B1System and method for detecting flight movements
Publication Date: 2024.03.20 HENSOLDT SENSORS GMBH
  • EP3604131B1 patent drawingFigure 1
  • EP3604131B1 patent drawingFigure 2
  • EP3604131B1 patent drawingFigure 3

AI summary

A system for detecting the flight movement (B) of an unmanned aircraft (10) having a transponder (12) comprises: at least two detection modules (111, 112) for detecting the unmanned aircraft (10) along the flight movement (B) by querying the transponder (12); and at least one control module (120) for triggering the query of the transponder (12) and for evaluating transmitted data from the transponder (12), wherein the evaluation includes identifying the unmanned aircraft (10) and its flight movement (B).