Handheld Geodesic Device Multipath Error Compensation

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Solution Overview

Problem

Current GNSS-based navigation systems face challenges in achieving high accuracy, particularly in differential navigation/positioning applications, due to multipath errors caused by signal reflections, especially when the rover and base are moving, and the need for precise relative positioning in environments with obstacles like foliage or buildings.

Innovation Solution

A handheld geodesic device that captures images from multiple known points to determine the position of an unknown point using GNSS signals, horizon sensors for orientation correction, and image processing algorithms to improve positioning accuracy, even in obstructed environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If differential navigation/positioning is used to improve positioning accuracy, then positioning accuracy is improved, but multipath errors from signal reflections worsen measurement reliability

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

Solution Approach 1:

The patent converts the harmful multipath effect into a useful measurement by detecting reflected GNSS signals and using them to determine reflection characteristics of surfaces. The system identifies that multipath signals carry information about surface properties and uses this information to improve rather than degrade positioning accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces image sensors as intermediaries to capture visual information about the environment and surfaces. These images serve as mediators between the GNSS signals and the processing system, enabling the system to identify reflection characteristics and compensate for multipath errors through image-based analysis

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If carrier phase measurements are used to improve measurement accuracy, then measurement accuracy improves to within a small fraction of carrier wavelength, but the system becomes more sensitive to multipath errors

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmultipath error sensitivity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful multipath effect into a useful measurement by detecting reflected GNSS signals and using them to determine reflection characteristics of surfaces. The system identifies that multipath signals carry information about surface properties and uses this information to improve rather than degrade positioning accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements feedback by using image sensors to continuously monitor surface characteristics and environment changes that affect signal reflections. This visual feedback is processed to identify reflection characteristics, which then feed back into the positioning algorithm to compensate for multipath errors in real-time

Inventive Principle:
Principle #23Feedback

3Measurement precision

If a base receiver is used to provide differential corrections to improve positioning accuracy, then positioning accuracy is improved, but the system complexity and reliance on external infrastructure increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the rover receiver to serve itself by equipping it with image sensors and processing capabilities to independently detect and characterize multipath reflections. The system performs its own error characterization and compensation without requiring external base station infrastructure, making the system self-sufficient

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent makes the rover receiver multi-functional by integrating image sensing capabilities alongside GNSS reception. The same device that receives positioning signals also captures visual data for environmental analysis and multipath characterization, eliminating the need for separate base station infrastructure

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

4Ease of operation

If traditional GNSS receivers are used in obstructed environments, then positioning is achieved, but accuracy deteriorates due to signal blockage and multipath reflections

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

Solution Approach 1:

The patent introduces image sensors as intermediaries to capture visual information about the environment and surfaces. These images serve as mediators between the GNSS signals and the processing system, enabling the system to identify reflection characteristics and compensate for multipath errors through image-based analysis

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements feedback by using image sensors to continuously monitor surface characteristics and environment changes that affect signal reflections. This visual feedback is processed to identify reflection characteristics, which then feed back into the positioning algorithm to compensate for multipath errors in real-time

Inventive Principle:
Principle #23Feedback

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

Enhances positioning accuracy by compensating for multipath errors and orientation issues, allowing for precise relative positioning of moving objects, such as aircraft or vehicles, with improved productivity and reduced reliance on external base stations.

Implementation Method 1

by measuring the carrier phase of the signal received from a satellite in the base receiver and comparing it with the carrier phase of the same satellite measured in the rover receiver

Methodology Applied
Scientific EffectCarrier phase measurement:

Implementation Method 2

A first image is captured of the first point using an image sensor; the first image includes the unknown point and at least one of the second point or the third point

Methodology Applied
Scientific EffectImage capture: Photography

Implementation Method 3

horizon sensors for orientation correction

Methodology Applied
Scientific EffectHorizon sensing:

Data Source

PatentUS10613231B2Portable GNSS survey system
Publication Date: 2020.04.07 JAVAD GNSS INC
  • US10613231B2 patent drawing
  • US10613231B2 patent drawing
  • US10613231B2 patent drawing

AI summary

A method for using a GNSS device to determine a position of an unknown point includes determining positions of a first point, a second point, and a third point using the GNSS device. A first image is captured of the first point using an image sensor, the image includes the unknown point and at least one of the second point or the third point. A second image is captured from the second point; the second image includes the unknown point and at least one of the second point or the third point. A third image is captured from the third point; the third image includes the unknown point and at least one of the second point or the first point. A position of the unknown point is calculated based on the first, second, and third images and the first, second, and third positions.