Soil Cultivation Robot GNSS Positioning Under Multipath Interference

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Solution Overview

Problem

Current robotic vehicles for soil cultivation face challenges in achieving precise positioning due to multipath errors and interference from satellite signals, especially in areas with obstacles, which can lead to inaccurate location determination and navigation.

Innovation Solution

The use of a dual GNSS signal approach, where a fixed vehicle base provides a first set of GNSS signals for reference, and the vehicle receives a second set of signals for location determination, allowing for comparison of signal qualities to identify and exclude low-quality signals, combined with predictive methods using Ephemerides and Almanacs to forecast future accuracy, ensuring high-precision navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single GNSS receiver is used for location determination, then the device complexity is reduced, but the measurement precision deteriorates due to multipath errors and signal interference

Engineering Contradiction:
ImproveGNSS system structureVSAvoidlocation determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system divides the GNSS reception function into two separate receivers: a first GNSS receiver at a fixed base location and a second GNSS receiver on the movable vehicle. This segmentation allows the base receiver to provide reference measurements for comparing against the vehicle receiver's measurements, enabling identification and correction of multipath errors and signal interferences that would affect a single receiver's accuracy.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If GNSS signals are used in areas with obstacles, then the adaptability of the vehicle is improved, but the measurement precision deteriorates due to multipath errors

Engineering Contradiction:
Improveoperation in obstructed areasVSAvoidlocation determination accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously comparing the second set of GNSS signals received by the vehicle with the first set of signals received by the base. This comparison provides feedback information about signal quality and multipath effects, allowing the system to identify degraded signals and either correct them or exclude them from position calculations, thereby maintaining accuracy even when operating in areas with obstacles.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3696574B1Robotic vehicle for soil cultivation
Publication Date: 2024.09.04 STIGA S P A IN BREVE ANCHE ST SPA
  • EP3696574B1 patent drawingFigure 1~2
  • EP3696574B1 patent drawingFigure 3A~3D
  • EP3696574B1 patent drawingFigure 4~5

AI summary

The invention relates to a robotic vehicle (100) for movable operation in a work area (108), the movable operation comprising a soil cultivation, the work area (108) being represented by a set of discretized coordinate grid points (112), the vehicle (100) comprising a Global Navigation Satellite System, GNSS, receiver (106) and a controller (118), the controller (118) comprising a memory (122) and a processor, the memory (122) comprising instructions (124), wherein execution of the instructions (124) by the processor causes the vehicle (100) for each grid point of a subset of the grid points (112) at different first points in time performing an initialization process, the initialization process comprising : - receiving at the first point in time a first set of GNSS signals (114) from a vehicle base (104), the vehicle base (104) being spaced apart from the vehicle (100), - receiving at the first point in time a second set of GNSS signals (116) from the GNSS receiver (106), - determining an accuracy of a location determination, the location determination being based on the second set of GNSS signals (116), the determination of the accuracy being based on a comparison of the signal qualities of the first set of GNSS signals (114) and the second set of GNSS signals (116).