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The Role of the TRS in Precision Agriculture: DGPS with EGNOS and RTK Positioning Using Data from NTRIP Streams

  • I. OsórioEmail author
  • M. Cunha
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 138)

Abstract

For Precise Agriculture purposes, several steps of a maize crop-system were recorded by the use of a GPS receiver with EGNOS and RTK capabilities. The field is about 35 km far from two GNSS CORS, one from RENEP, operated by IGS, and the other from SERVIR, operated by IGEoE. Both networks disseminate real-time GNSS data streams over the Internet using the NTRIP protocol. The GNSS data streams from RENEP reference stations (including validated station coordinates) provide the user with a real-time access to the ETRS89 and, those same streams from IGEoE, a military institution, are in ITRS, allowing large scale scientific applications. The validation of the EGNOS and the RTK solutions, obtained in the two TRS systems, was achieved by the results from post-processed measurements. RTK solutions, when compared to the post-processed values in the same TRS, show sub-decimeter accuracy what is enough for many of the Precision Agriculture studies. However, the two RTK solutions have a translation with a magnitude of the order of 0.5 m that can be explained by the independence of the ETRS89 on the continental drift. Indeed, at the zone where the field is located, while the ETRFyy Cartesian coordinates have velocities less than 1 mm/year, the ITRFyy Cartesian coordinates have velocities greater than 1 cm/year, what give rise to a point position variation with a magnitude of 2.5 cm/year.

In order to correlate the tractor velocity, during a pre-emergence herbicide application, to the terrain slope, the field orthometric heights were obtained by the use of GRS80 ondulations, on a 1.5′ × 1.5′grid, in the local Portuguese geoid model GeodPT08. The global precision of this model is estimated in 4 cm, which is within the error for the real time solutions obtained.

Keywords

Precision agriculture TRS RTK positioning GNSS SBAS GBAS 

Abbreviations

CORS

Continuously Operating Reference Station

DGPS

Differential GPS

DORIS

Détermination d’Orbite et Radiopositionnement Intégrés par Satellite

EGNOS

European Geostationary Navigation Overlay Service

EPN EUREF

Permanent Network

ETRF

European Terrestrial Reference Frame

ETRS89

European Terrestrial System coincident with ITRS at the epoch 1989.0

GBAS

Ground-Based Augmentation System

GNSS

Global Navigation Satellite System

GPS

Global Positioning System

GRS80

Geodetic Reference System 1980

IERS

International Earth Rotation and Reference Systems Service

IGEoE

Instituto Geográfico do Exército

IGS

International GNSS Service

ITRS

InternationalTerrestrialReferenceSystem

ITRF

InternationalTerrestrialReferenceFrame

IGP

Instituto Geográfico Português

LLR

Lunar Laser Ranging

NTRIP

Network Transport of RTCM via Internet Protocol

RENEP

REde Nacional de Estações Permanentes (National CORS network)

RTCM

Radio Technical Commission for Maritime Services

RTK

Real Time Kinematic

SERVIR

Sistema de Estações de Referência VIRtuais (GNSS CORS operatingundertheconceptof VRS)

SBAS

Satellite-Based Augmentation System

SLR

Satellite Laser Ranging

TRF

Terrestrial Reference Frame

TRS

Terrestrial Reference System

VLBI

Very Long Baseline Interferometry

VRS

Virtual Reference Station

WAAS

Wide Area Augmentation System

Notes

Acknowledgements

Geo-Space Sciences Research Centre, Faculty of Sciences, University of Porto, financially supported by the Foundation for Science and Technology (FCT). Thanks are also due to Mr. P. Veloso for helping with fieldwork at “Qta de Crujes”.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  1. 1.Faculdade de CiênciasUniversidade do PortoPortoPortugal

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