Drone RF Detection Using RANSAC Frequency Hopping Estimation

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Solution Overview

Problem

Current drone detection systems face challenges in accurately estimating frequency hopping parameters in real-time, especially under conditions of gross errors, timing errors, and multiple target scenarios, which affects their ability to effectively detect and mitigate unauthorized drone activities.

Innovation Solution

The implementation of a frequency hopping parameter estimation method based on the random sample consensus (RANSAC) algorithm, which allows for accurate estimation using a small set of samples and is robust to errors, enabling real-time detection and mitigation of drones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional frequency hopping parameter estimation methods are used, then the system can detect drones, but the accuracy deteriorates under conditions of gross errors, timing errors, and multiple target scenarios

Engineering Contradiction:
Improvefrequency hopping parameter estimation accuracyVSAvoiddetection reliability under errors and multiple targets
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the frequency hopping signal analysis into multiple independent parameter estimation processes. Each parameter (frequency, time, bandwidth) is estimated separately using RANSAC, allowing the system to handle gross errors in individual parameters without compromising overall detection accuracy. This segmentation enables robust parameter estimation even when some measurements are corrupted by timing errors or interference from multiple drones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary signal acquisition and preprocessing before parameter estimation. By collecting a sufficient number of signal samples and pre-processing them to extract potential frequency hopping patterns, the system prepares clean input data for the RANSAC algorithm. This preliminary action ensures that the main parameter estimation stage receives high-quality data, improving accuracy even in noisy environments with multiple targets.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If more samples are collected for parameter estimation, then accuracy improves, but the detection time increases

Engineering Contradiction:
Improveparameter estimation accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The RANSAC algorithm implements partial action by randomly selecting a subset of samples (typically 3-5 points) from the available signal data for each parameter estimation iteration. This partial sampling approach provides sufficient accuracy for frequency hopping parameter estimation without requiring processing of the entire signal dataset, thereby maintaining real-time detection capability while achieving robust accuracy even in the presence of gross errors.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system skips unnecessary processing steps by directly applying RANSAC to estimate parameters from randomly selected samples, rather than processing all samples sequentially. This rushing through the estimation process with minimal samples per iteration enables rapid parameter acquisition, reducing detection time while maintaining accuracy through the iterative nature of RANSAC that quickly converges on correct parameter values.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Use of energy by moving object

If the system tolerates higher false alarm rates, then it can operate in low signal-to-noise ratio conditions, but the measurement precision deteriorates

Engineering Contradiction:
Improvesignal detection capability in low SNRVSAvoidparameter estimation precision
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of low signal-to-noise ratio and potential gross errors into a benefit by using RANSAC's iterative random sampling approach. The algorithm randomly selects sample subsets and evaluates them, which means that even if some samples are corrupted by noise or represent false alarms, the correct parameter values will emerge consistently across multiple iterations. This transforms the presence of noise and false alarms from a detrimental factor into a manageable condition that the algorithm is designed to handle.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The RANSAC implementation includes feedback mechanisms where each iteration evaluates the quality of parameter estimates by checking how well they fit the observed signal data. The algorithm uses this feedback to accept or reject parameter estimates and continues iterating until convergence or a maximum number of iterations is reached. This feedback loop allows the system to maintain precision by continuously refining estimates even in low SNR conditions where initial measurements may be inaccurate or represent false alarms.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3977626B1Systems and methods for detecting, monitoring, and mitigating the presence of a drone using frequency hopping
Publication Date: 2024.06.12 SKYSAFE INC
  • EP3977626B1 patent drawingFigure 1
  • EP3977626B1 patent drawingFigure 2A
  • EP3977626B1 patent drawingFigure 2B~2C

AI summary

Systems and methods for detecting, monitoring, and mitigating the presence of a drone are provided herein. In one aspect, a system for detecting presence of a one or more drones includes a radio-frequency (RF) receiver configured to receive an RF signal transmitted between a drone and a controller. The system can further include a processor and a computer-readable memory in communication with the processor and having stored thereon computer-executable instructions to cause the at least one processor to receive a set of samples from the RF receiver for a time interval, the set of samples comprising samples of the first RF signal, obtain a parameter model of the first frequency hopping parameters, and fit the parameter model to the set of samples.