Geolocation Receiver Synchronization Validation Using Ephemeris Word Extraction

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Solution Overview

Problem

Current methods for validating synchronization between a geolocation receiver and a transmitting satellite during the acquisition phase are inefficient, often requiring a complete decoding of ephemeris data sets and comparison with almanac data, which takes a long time, especially in systems like GPS and SBAS, leading to potential false synchronization and distorted positioning.

Innovation Solution

A method that validates synchronization using only part of the ephemeris words received, reducing the time required to confirm the absence or presence of false synchronization by implementing a probability-based validation process that compares extracted ephemeris words with stored values, allowing for rapid identification of cross-correlation errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complete ephemeris data sets are decoded and compared with almanac data to validate synchronization, then the reliability of synchronization validation is improved, but the time required for validation increases significantly

Engineering Contradiction:
Improvesynchronization validation reliabilityVSAvoidvalidation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts only the necessary ephemeris words (specifically words 0, 4, 8, 12, 16) from the complete ephemeris data set for validation purposes. This extraction principle allows the system to validate synchronization without processing all ephemeris data, thereby reducing validation time while maintaining reliability through targeted comparison of critical satellite position information.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the ephemeris validation process into discrete, independently processable ephemeris words. By dividing the complete ephemeris data set into individual words and selectively validating only specific ones, the system achieves faster validation without compromising the overall reliability of synchronization confirmation.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If traditional synchronization validation methods are used, then the accuracy of positioning information is ensured, but the productivity of the geolocation system decreases due to long validation times

Engineering Contradiction:
Improvepositioning information accuracyVSAvoidsystem response speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-identifying which ephemeris words are critical for synchronization validation (words 0, 4, 8, 12, 16). This preliminary selection allows the system to focus validation efforts on only these essential words, maintaining positioning accuracy while significantly improving system response speed by avoiding processing of non-critical data.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements partial action by validating only a subset of ephemeris words rather than the complete data set. This partial validation approach is sufficient to ensure positioning accuracy while dramatically reducing the computational burden and improving productivity.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If all ephemeris words are processed for synchronization validation, then the integrity of navigation information is improved, but the device complexity and processing requirements increase

Engineering Contradiction:
Improvenavigation information integrityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential ephemeris words needed for synchronization validation (words 0, 4, 8, 12, 16), eliminating the need to process the complete ephemeris data set. This extraction reduces processing complexity while maintaining navigation information integrity through focused validation of critical satellite position data.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3179276B1Methods and devices for validating the synchnonization between a geolocalizing receptor and an emitting satellite
Publication Date: 2023.07.05 THALES SA
  • EP3179276B1 patent drawingFigure 1
  • EP3179276B1 patent drawingFigure 2
  • EP3179276B1 patent drawingFigure 3

AI summary

The invention relates to a method for validating synchronization between a geolocation receiver (12) with an identified transmitting satellite, the receiver (12) being capable of receiving a composite radio signal comprising a plurality of navigation signals each emitted by a transmitting satellite belonging to a constellation of satellites (4, 6, 8), as well as a method for validating synchronization between a geolocation receiver (12) with a transmitting satellite (10) during an acquisition phase of an augmentation signal comprising geolocation correction and integrity data.The method of the invention comprises, for each identified transmitting satellite (4, 6, 8, 10), the extraction of received ephemeris words or words of any type from the received signal associated with the identified satellite as it is received, and the comparison of at least one received word with at least one word of the same rank received or stored for said identified satellite and/or for at least one other satellite. The validation or failure of synchronization with said identified transmitting satellite depends on a predetermined probability of false alarm and/or probability of non-detection.