GNSS Spoofing Detection via Orbital Prediction

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Solution Overview

Problem

Global navigation satellite system (GNSS) spoofing poses a significant threat to avionics safety by causing GNSS receivers to output erroneous position data, potentially leading to catastrophic hazards during flight or landing, as it affects critical aircraft systems and deteriorates required navigation performance.

Innovation Solution

A method and system for detecting satellite signal spoofing by monitoring and comparing current and predicted orbital information values, such as satellite position and Doppler shift, to generate a spoofing alert signal when discrepancies exceed threshold levels, allowing for corrective actions to be taken.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If GNSS receivers use standard 24 channel receiver design, then the device complexity is reduced and ease of operation is improved, but the reliability deteriorates due to susceptibility to spoofing threats

Engineering Contradiction:
Improvespoofing resistanceVSAvoidreceiver design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by continuously monitoring satellite orbital information and calculating predicted values before spoofing can occur. The spoofing detection system pre-computes expected satellite positions, Doppler shifts, and dilution of precision values, then compares these predictions with actual received signals to detect anomalies before they compromise navigation safety.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously comparing predicted orbital information with actual satellite signal data. When discrepancies exceed threshold levels, the system generates spoofing alert signals that feed back to the navigation system, enabling real-time detection and response to spoofing threats without requiring fundamental changes to the receiver architecture.

Inventive Principle:
Principle #23Feedback

2Reliability

If GNSS receivers output position data continuously, then the productivity is improved for navigation systems, but the loss of information increases when spoofing occurs

Engineering Contradiction:
Improveposition data accuracyVSAvoiderroneous position output
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system uses feedback by continuously monitoring satellite signal parameters and comparing them against predicted values. When spoofing is detected through discriminator value analysis, the feedback mechanism triggers alerts that prevent the propagation of erroneous position data to navigation systems, ensuring that position information integrity is maintained even during spoofing events.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies preliminary anti-action by detecting spoofing threats before they can corrupt navigation position outputs. The continuous comparison of actual versus predicted orbital information enables the system to identify and counteract spoofing attempts proactively, preventing erroneous position data from being generated in the first place.

Inventive Principle:
Principle #9Preliminary anti-action

3Measurement precision

If spoofing detection systems monitor all satellite parameters continuously, then the measurement precision is improved for detecting spoofing, but the use of energy increases

Engineering Contradiction:
Improveorbital information accuracyVSAvoidreceiver energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system applies partial action by selectively monitoring and comparing specific satellite orbital parameters (orbital position, Doppler shift, dilution of precision) rather than all possible signal characteristics. This targeted approach maintains sufficient measurement precision for spoofing detection while reducing computational load and energy consumption compared to comprehensive continuous monitoring of all satellite signal parameters.

Inventive Principle:
Principle #16Partial or excessive action

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

The solution effectively detects and mitigates GNSS spoofing threats, ensuring improved safety by alerting vehicle systems and regulatory authorities, allowing for the avoidance of vulnerable locations and maintaining seamless navigation and required navigation performance.

Implementation Method 1

the current one or more orbital information values comprise satellite orbital position, Doppler shift, or dilution of precision

Methodology Applied
Scientific EffectDoppler shift: Doppler Effect

Data Source

PatentEP4336220A1GNSS spoofing threat detection and corrective action
Publication Date: 2024.03.13 HONEYWELL INTERNATIONAL INC
  • EP4336220A1 patent drawingFigure 1
  • EP4336220A1 patent drawingFigure 2
  • EP4336220A1 patent drawingFigure 3

AI summary

A method for detecting spoofing comprises monitoring GNSS satellite signals with a GNSS receiver; obtaining current time, current orbital information values, Doppler shift, and/or dilution of precision from the GNSS receiver, with the current orbital information values comprising orbital position with respect to a current position of the GNSS receiver; retrieving past orbital information values comprising orbital position, and calculating predicted orbital information values based on the past orbital information values, with respect to the current time from the receiver, with the predicted orbital information values comprising orbital position with respect to the current position of the receiver. The method compares the predicted orbital information values, Doppler shift, and/or dilution of precision, with the current orbital information values to obtain discriminator values; determines whether the discriminator values are greater than threshold levels; and outputs a spoofing alert signal when the discriminator values are greater than the threshold levels.