GPS Jammer Detection via Inertial Navigation Error Analysis

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Solution Overview

Problem

Current methods for detecting and mitigating GPS jamming and spoofing are either hardware-dependent, computationally expensive, or require modifications, making them inefficient and costly, especially in scenarios where rapid detection and minimal interference are crucial.

Innovation Solution

A software-based system that utilizes high-fidelity error models of Inertial Navigation Systems (INS) to detect GPS interference by computing sampled-autocorrelation functions and power spectral density, comparing INS and GPS position data, and implementing algorithms to identify deterministic errors caused by jamming or spoofing, which are immune to external interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If antenna nulling is used to minimize jamming effects, then interference attenuation is improved, but GPS signal loss increases when interference source is close to receiver

Engineering Contradiction:
Improvejamming interference attenuationVSAvoidGPS signal reception reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces an intermediary detection system that monitors GPS signal characteristics and identifies jamming/s spoofing conditions before they severely impact navigation. This intermediary detection layer allows the system to recognize interference sources and switch to alternative navigation modes (such as INS-only operation) without requiring aggressive antenna nulling that would cause signal loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If enhanced signal processing techniques are used to increase anti-jam capabilities, then interference resistance is improved, but computational cost increases

Engineering Contradiction:
Improveinterference resistanceVSAvoidcomputational energy consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by implementing a tiered detection approach that uses lightweight statistical tests (such as chi-square tests on signal power spectral density) rather than full-spectrum enhanced signal processing. The system performs basic monitoring continuously and only activates more intensive analysis when anomalies are detected, reducing overall computational energy consumption while maintaining adequate interference resistance.

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If 3rd GPS frequency receivers are deployed to minimize sensitivity to interference, then anti-jam capability is improved, but integration time and cost increase

Engineering Contradiction:
Improveinterference sensitivity reductionVSAvoidtechnology integration time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent creates a virtual model of expected GPS signal characteristics using Inertial Navigation System (INS) data and compares actual GPS signals against this model. This software-based copying approach replicates the functionality of hardware frequency diversity without requiring physical 3rd frequency receivers, thereby avoiding the long integration times and high costs associated with deploying new hardware frequencies.

Inventive Principle:
Principle #26Copying

4Ease of manufacture

If software-based detection methods are used to identify GPS interference, then hardware modification is avoided, but detection accuracy may be insufficient without enhanced processing

Engineering Contradiction:
Improvesystem implementation simplicityVSAvoidinterference detection accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent segments the interference detection problem into multiple independent analytical components: power spectral density analysis, autocorrelation function examination, chi-square statistical testing, and INS-GPS position discrepancy analysis. Each segment focuses on a specific aspect of signal characteristics, and the combination of these segmented analyses achieves high detection accuracy while keeping each individual software module computationally efficient and easy to implement.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3519862B1GPS jammer & spoofer detection
Publication Date: 2023.07.19 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC
  • EP3519862B1 patent drawingFigure 1
  • EP3519862B1 patent drawingFigure 2
  • EP3519862B1 patent drawingFigure 3A~3B

AI summary

A method for determining the presence of interference on a GPS receiver is described. The method involves monitoring global positioning system data received by a receiver under known non-interfering conditions, storing the data for analysis and, at a later time, comparing the data, over a period of time, with the position output of a pure inertial navigation system to determine the presence of characteristics indicating interference.