5G Satellite Positioning Validation via Propagation Time

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Solution Overview

Problem

Current 5G satellite communication systems face challenges in accurately verifying the geographical position of user terminals due to large satellite cells and limited coverage, leading to unreliable GNSS position measurements, which affects routing, billing, and legal interception, especially in geostationary deployments with wide cells and low-precision positioning.

Innovation Solution

A method that involves determining first positioning data from user terminals via GNSS, second positioning data from propagation channel measurements by user terminals, and third positioning data from proximity base stations, with these data sets being compared in the 5G core network to validate the user terminal's position, using secret keys and electromagnetic fingerprints to secure the link.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GNSS coordinates are used for positioning in satellite networks, then the user terminal can determine its position, but the position data can be easily altered and is not reliable for network verification

Engineering Contradiction:
Improvepositioning accuracyVSAvoidposition data trustworthiness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the network verifies the GNSS position reported by the user terminal by comparing it with independently measured positioning data. The network measures the propagation time of signals between the user terminal and satellite, calculates the expected position, and feeds back validation results to determine whether to accept or reject the reported position, ensuring reliability of positioning data.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary verification mechanism where the network acts as a mediator to validate the positioning data. Instead of directly trusting the user terminal's GNSS report, the network intermediates by performing independent measurements through satellite signal propagation time analysis and comparing results to verify the authenticity of the position data before accepting it for billing and routing purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If conventional positioning techniques are used in satellite networks, then positioning can be implemented, but satellite cells are very large and geographical areas are not covered by multiple cells simultaneously

Engineering Contradiction:
Improvepositioning implementationVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces conventional terrestrial positioning methods with a satellite-based propagation time measurement system. Instead of relying on terrestrial base station triangulation which requires multiple overlapping cells, the system uses the satellite's orbital position and signal propagation time to calculate user terminal position, adapting the positioning mechanism to the satellite network's large cell structure and single-satellite coverage scenario.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental measurement parameter from terrestrial signal strength or angle-based positioning to satellite signal propagation time measurement. By measuring the time it takes for signals to travel between the satellite and user terminal and using the known satellite orbital parameters, the system achieves accurate positioning in large satellite cells without requiring multiple overlapping coverage areas.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If only one satellite or one NTN cell covers the service area, then satellite communication is possible, but new pilots like PRS and SRS become difficult to implement

Engineering Contradiction:
Improvesatellite coverage flexibilityVSAvoidpositioning signal implementation
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the existing satellite communication signals serve multiple functions. The same signals used for basic communication and timing synchronization are also utilized for positioning measurements. By extracting propagation time information from routine communication signals rather than requiring separate dedicated positioning pilots, the system achieves positioning capability with a single satellite or NTN cell without increasing device complexity or requiring additional signal infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a self-service positioning approach where the user terminal and network use existing communication signals for both communication and positioning purposes. The system leverages the necessary uplink and downlink signals already required for satellite communication to perform positioning measurements, eliminating the need for separate positioning signal infrastructure and reducing implementation complexity in single-satellite scenarios.

Inventive Principle:
Principle #25Self-service

4Area of stationary object

If geostationary satellites with wide cells are used, then large coverage area is achieved, but positioning accuracy remains very low

Engineering Contradiction:
Improvecoverage areaVSAvoidpositioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent performs preliminary measurements and calculations of signal propagation time before final position determination. By measuring the propagation time with high precision and using pre-calculated satellite orbital parameters and positions, the system compensates for the large cell size effect. The preliminary accurate time measurement allows calculation of precise position even when the satellite covers a large geographical area, overcoming the limitation of wide cell positioning accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4207889A1Method for validating a positioning of a user terminal in a 5g cell network
Publication Date: 2023.07.05 THALES SA
  • EP4207889A1 patent drawingFigure 1
  • EP4207889A1 patent drawingFigure 2
  • EP4207889A1 patent drawingFigure 3

AI summary

The invention relates to a 5G communication system comprising a 5G cellular radio network, each cell of said 5G cellular radio network comprising at least one base station, each base station being adapted to communicate with a 5G-compatible user terminal (UE). The communication system comprises a satellite (Sat), said satellite (Sat) being adapted to exchange service frames (TS) with the user terminal (UE), a gateway (GW), said gateway (GW) being adapted to exchange feeder link frames (TLF) with the satellite (Sat), a 5G core network (5GC), said core network (5GC) being connected to the gateway (GW), said core network (5GC) being capable of communicating with the base stations. The user terminal (UE) is capable of communicating at any given time with several base stations, referred to as proximity base stations (gNB1,..., gNBi, ..., gNBn).