Safe Ephemeris Data Verification for Spoofing-Resistant RTK Positioning

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Solution Overview

Problem

Real-time kinematic (RTK) GNSS systems are vulnerable to spoofing, jamming, and interference, which can lead to inaccurate carrier phase measurements and ephemeris data, affecting the reliability of position computation.

Innovation Solution

A method is introduced to transmit safe correction data from a base station to a rover, where the safe ephemeris data is verified to be unaffected by spoofing, allowing for the comparison with reference ephemeris data to determine signal authenticity, and only trusted data is used for position computation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If RTK GNSS systems use carrier phase measurements for high precision positioning, then measurement precision is improved, but the system becomes vulnerable to spoofing and interference

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsignal authenticity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces safe ephemeris data as an intermediary verification layer between the satellite signals and the position computation. The base station receives and validates ephemeris data from multiple sources, compares them for consistency, and only transmits verified safe ephemeris data to the rover. This intermediary validation process protects the high-precision RTK positioning system from spoofing attacks without reducing measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the system transmits correction data from base station to rover, then positioning accuracy is improved, but the transmission of unverified data may propagate spoofing errors

Engineering Contradiction:
Improveposition accuracyVSAvoidspoofing propagation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary verification of ephemeris data at the base station before transmission to the rover. The base station receives ephemeris data, performs consistency checks by comparing multiple sources, validates the data for spoofing indicators, and only then transmits the verified safe ephemeris data along with correction data. This preliminary action prevents spoofing errors from being propagated to the rover while maintaining the benefits of correction data transmission for accurate positioning.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the system implements comprehensive signal verification, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesignal authenticityVSAvoidverification process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service verification mechanism where the base station autonomously performs ephemeris data validation by receiving data from multiple sources, comparing consistency, detecting spoofing indicators, and automatically determining which data to transmit. The system also enables the rover to self-verify received data against computed expectations. This self-service approach improves reliability through comprehensive verification while minimizing the need for external intervention or manual configuration, thereby controlling system complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4365635A1Rover position computation using safe data
Publication Date: 2024.05.08 TRIMBLE INC
  • EP4365635A1 patent drawingFigure 1
  • EP4365635A1 patent drawingFigure 2
  • EP4365635A1 patent drawingFigure 3

AI summary

Described herein are systems, methods, and other techniques for computing a position of a rover using satellite signals from a plurality of satellites. Safe ephemeris data may be received at a base station. The safe ephemeris data may indicate positions of the plurality of satellites. The safe ephemeris data may be wirelessly transmitted from the base station to the rover. Rover carrier-phase measurements may be obtained based on the satellite signals received at the rover. The position of the rover may be computed using at least the rover carrier phase measurements and the safe ephemeris data.