Hybrid RTK Engine Positioning Accuracy Multipath Errors

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Solution Overview

Problem

GNSS devices face challenges in achieving accurate position measurements in conditions where receiving correction signals is difficult, such as under obstructions like trees or buildings, due to multipath errors and obscured line-of-sight to satellites.

Innovation Solution

The method involves storing raw GNSS data when accurate measurements cannot be made, allowing for post-processing to obtain accurate position data, and utilizing a hybrid RTK engine verification process that includes receiving GNSS signals and correction signals from a base unit, with algorithms to determine position data and handle errors like multipath errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If real-time RTK algorithm is used to determine position, then positioning speed is improved, but positioning accuracy deteriorates when correction signals are obscured or multipath errors occur

Engineering Contradiction:
Improvepositioning speedVSAvoidpositioning accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent stores raw GNSS signal data and base station data in advance before post-processing. By preliminarily collecting and preserving the raw measurement data, the system enables accurate position determination through post-processing even when real-time correction signals are obscured or contaminated by multipath errors, thus resolving the contradiction between positioning speed and accuracy.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If differential corrections are applied in real-time, then positioning accuracy is improved, but reliability deteriorates when base-to-rover communication is obscured

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary post-processing step that mediates between the rover's raw measurements and the base station data. When real-time correction signals are obscured, the system uses the stored raw data as an intermediary to perform offline differential correction, maintaining positioning reliability without sacrificing accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If carrier phase measurements are used to improve accuracy, then measurement precision is improved, but device complexity increases due to additional processing requirements

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs carrier phase ambiguity resolution and complex differential corrections in advance during post-processing using stored raw data. By preliminarily completing these complex processing tasks offline, the system achieves high measurement precision without requiring complex real-time processing capabilities, thus reducing device complexity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3408686B1Hybrid rtk
Publication Date: 2023.06.07 JAVAD GNSS INC
  • EP3408686B1 patent drawingFigure 1
  • EP3408686B1 patent drawingFigure 2
  • EP3408686B1 patent drawingFigure 3

AI summary

A GNSS deice includes executable instructions for several steps, A first algorithm is executed to determine first position data for the GNSS device based on the first plurality of GNSS signals and a correction signal received at the GNSS device from the GNSS base unit. The first position data is stored memory of the GNSS device. A second algorithm is executed to determine second position data for the GNSS device based on the second plurality of GNSS signals. In response to the second algorithm failing to determine the second position data, GNSS signal data is stored in memory of the GNSS device. The GNSS signal data is based on the second plurality of GNSS signals. The GNSS signal data are transmitted to an external device.