User Terminal/Local Element System for Network Based Positioning using RTK/EGNOS in Urban Environment

Antonio Defina, Khalid Charqane, Fabrizio Dominici, Gianluca Marucco, Chiara Porporato, Mattia De Agostino, Ambrogio M. Manzino

Abstract:	This paper proposes an architectural solution for the exploitation and test of different augmentation systems for Global Navigation Satellite System (GNSS) receivers in urban environment. Such architecture, referring to the network based concept, relies on a Local Element (LE) linked through a communication network to some mobile units, called User Terminals (UTs). In the specific case the UT is built up with a laptop and a professional single frequency GPS sensor. The sensor is fully handled by the software running on the laptop. Such software was completely developed by the authors and allows a flexible managing of the sensor and of the differential corrections made available by the LE. It represents the interface of the system to the DGPS/RTK network. In particular, the LE gets data implementing the Networked Transport of RTCM via Internet Protocol (NTRIP). The user can select a particular augmentation service through a connection with the LE. In the GBAS case the choice is among different services involving different concepts for the correction calculation and use; ranging from simple differential correction (for code based positioning) to N-RTK. An interesting feature of the system is the possibility to perform the position computation by the LE side: raw measurements data are collected by an appropriate driver running on the UT laptop and sent to the LE. Here specific algorithms can be used to process raw data and differential data to compute a position with different strategies. The overall system can be based on different communication networks: preliminary test were performed with General Packet Radio Service (GPRS), mesh networks and Digital Mobile Radio (DMR). A geodetic dual frequency receiver has been being used in order to obtain a reference solution as a benchmark for the tests results
Published in:	Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008) September 16 - 19, 2008 Savannah International Convention Center Savannah, GA
Pages:	356 - 367
Cite this article:	Defina, Antonio, Charqane, Khalid, Dominici, Fabrizio, Marucco, Gianluca, Porporato, Chiara, De Agostino, Mattia, Manzino, Ambrogio M., "User Terminal/Local Element System for Network Based Positioning using RTK/EGNOS in Urban Environment," Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008), Savannah, GA, September 2008, pp. 356-367.
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