Drone RF Frequency-Hopping Detection Under Noisy Multi-Target Signals

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Solution Overview

Problem

Current drone detection systems face challenges in accurately identifying frequency hopping parameters from noisy time-frequency samples, especially in multi-target scenarios, due to high implementation complexity and sensitivity to errors, which hinders real-time detection and mitigation capabilities.

Innovation Solution

The implementation of a frequency hopping parameter estimation method based on the random sample consensus (RANSAC) algorithm, which estimates parameters by fitting a model to observation data, classifying samples as inliers or outliers, and selecting the best model instance for accurate drone identification, enabling real-time detection with low complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If linear Least Squares methods are used for frequency hopping parameter estimation, then the implementation complexity is low, but the accuracy deteriorates under gross errors, timing errors, and multiple target scenarios

Engineering Contradiction:
Improveimplementation complexityVSAvoidparameter estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the frequency hopping signal analysis into multiple independent frequency bins, allowing parallel processing of different frequency components. This segmentation enables the RANSAC algorithm to evaluate multiple hypotheses simultaneously, improving accuracy without proportionally increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic hypothesis evaluation process where the RANSAC algorithm iteratively refines parameter estimates by randomly sampling data points and evaluating fitting errors. This dynamic approach adapts to varying signal conditions and error types, maintaining accuracy across different operational scenarios while managing computational complexity through adaptive iteration limits.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If RANSAC-based frequency hopping parameter estimation is implemented, then the accuracy improves under gross errors and multiple target scenarios, but the implementation complexity increases

Engineering Contradiction:
Improveparameter estimation accuracyVSAvoidimplementation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the frequency spectrum into multiple bins and processes each bin independently using the RANSAC algorithm. This segmentation allows the computationally intensive RANSAC method to be applied to smaller, manageable subsets of data, reducing the overall computational burden while maintaining high accuracy through parallel processing of frequency components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a limited number of RANSAC iterations (e.g., 10-100 iterations) rather than exhaustive search, providing a practical balance between accuracy and complexity. This partial action approach achieves sufficient parameter estimation accuracy for real-time drone detection without requiring computationally prohibitive exhaustive evaluation of all possible parameter combinations.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If frequency hopping parameters are accurately estimated in multi-target scenarios, then the drone identification accuracy improves, but the computational requirements and complexity increase

Engineering Contradiction:
Improvedrone identification accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the multi-target detection problem into multiple frequency bin analyses, where each bin independently estimates parameters for potential drones. This segmentation transforms a complex multi-target problem into multiple simpler single-frequency analysis tasks, enabling accurate drone identification in multi-target scenarios through parallel processing while managing computational complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary frequency binning and coarse parameter estimation before applying the full RANSAC algorithm. This preliminary action filters out obvious non-matching signals and prepares data structures that facilitate more efficient RANSAC execution, reducing the computational burden of accurate multi-target identification while maintaining high detection accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11894870B2Systems and methods for detecting, monitoring, and mitigating the presence of a drone using frequency hopping
Publication Date: 2024.02.06 SKYSAFE INC
  • US11894870B2 patent drawing
  • US11894870B2 patent drawing
  • US11894870B2 patent drawing

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.