International cooperation and technology transfer

Fras, Mojca Kosmatin

Bibliographic data

Monograph

Persistent identifier:: 856490555

Author:: Fras, Mojca Kosmatin

Title:: International cooperation and technology transfer

Sub title:: Ljubljana, Slovenia, February 2 - 5, 2000 : proceedings of the workshop

Scope:: VI, 163 Seiten

Year of publication:: 2000

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856490555

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: RESULTS OF DGPS EXPERIMENTS WITH DIFFERENT RTCM RADIO SOURCES IN THE CEI AREA. R. Cefalo, R. Pagurut, J. Plasil, T. Sluga

Document type:: Monograph

Structure type:: Chapter

RESULTS OF DGPS EXPERIMENTS WITH DIFFERENT RTCM RADIO SOURCES IN THE CEI AREA R. Cefalo *, R. Pagurut *, J. Plasil °, T. Sluga * * Department of Civil Engineering, University of Trieste, Italy ° Faculty of Electrical Engineering, Czech Technical University, Praha cefalo@dic.univ.trieste.it Commission VI, Working Group 3 KEY WORDS: DGPS, RTCM, LW transmission, FM transmission. ABSTRACT Several radio sources generating RTCM corrections are available in the CEI area, even without a full coverage. Some of them are simultaneously present in some areas, thus allowing static and kinematic analyses of accuracy and continuity. Our intent was to test some different RTCM correction sources received in one place, in order to compare the different accuracy of the systems. All this, in view of detecting one or more RTCM correction systems able to give satisfatorily accurate results with a full coverage on the CEI area. The considered DGPS radiodiffusion methods are two Low Frequency transmitted signals, i.e. ALF, and LF signal from Podebrady (Prague), and one FM transmitted signal: DARC. This paper reports the adopted techniques and the detailed results of some experiments performed together by different components of the CEI Working Group on Satellite Navigation Systems. 1. EXISTING METHODS At least the following DGPS radiodiffusion methods are available in the CEI area, some on a large area, others only locally, giving different positioning accuracy greatly due to the distance from the correction source: TERRESTRIAL ANTENNAS: - LOW FREQUENCY: ALF (Accurate Positioning by Low Frequency) operated by Bundesamt fuer Cartographie und Geodesie (BKG) in Frankfurt am Main; LF transmitter in Podebrady, a small town 50 km east of Prague, which transmits DGPS corrections generated in the Czech Technical University (CTU) Reference Station, in Prague; MARINE RADIOBEACON: Some years ago, an experimental emission from Venice, Punta Maestra by Italian Navy and Codevintec Italiana, Milan, was successfully experimented with a car trajectory from the top of the Apennine Highway to Trieste; -HIGH FREQUENCY (VHF,UHF): RDS (Radio Data System): It should be soon available for experiments in the Italian eastern highways; DARC (Data Radio Channel)/Swift (System for Wireless Infotainment Forwarding and Télédistribution) - the RTCM and RTK emission is a service by ORF (Österreichische Rundfunk) on the FM band; DAB (Digital Audio Broadcasting), about 250 MHz: Bavaria, province of Bozen (RAI and RAS); MOBILE TELEPHONES: Experiments were done with TACS, showing difficulties in maintaining the connection. These systems are very useful for research since there is no need of transmission licence, but the number of users is limited. TELECOM UNICATION SATELLITE EMISSIONS: RACAL: several experiments on the highways showed the feasibility of the method on open areas. The method is less feasible in urban areas, due to building covering; OMNISTAR: Same as RACAL; and EGNOS (European Geostationary Overlay Service): Same as RACAL. 2. THE CZECH TECHNICAL UNIVERSITY (CTU) REFERENCE STATION The Czech Technical University (CTU) Reference Station is based on three GPS receivers: 1. Leica MX9400R receiver 2. Trimble GPS Pathfinder Community Base Station 3. Novatel GPSCard 951R in 486 PC computer The Leica receiver is the core of the reference station and gives corrections which are disseminated wireless. The Trimble receiver generates corrections for postprocessing. It also backs up Leica. The Novatel Card is the first - and by now rather obsolete - receiver that backs up both receivers mentioned above. Corrections are broadcast with one-second step in real time by 1) VHFR(B)DS channel 2) LF channel Correction Dissemination by VHF RDS Channel cover Prague and its near surroundings. The data of pseudorange measurements made by Leica receiver modulate an LF transmitter in Podebrady (Fig. 1) - a small town 50 km east of Prague. The transmitter works on 111.8 kHz frequency, with a 500 bps bit rate. The transmitter output power is 80 kW. It is backed up by a 5 kW standby transmitter. Corrections are placed into 60 bit frames. FEC is provided by CRC code (60,41). The CTU designed and manufactured receivers for both LF and VHF channels. They receive signals, prove message parity, and ignore frames with detected errors. At receiver output, there are corrections in RTCM 104 format. LF signal coverage is shown in Fig. 2. It covers a large share of Central Europe. Flags mark the places where corrections were tested, even if by different GPS receivers. It was noticed that the accuracy of position determination first and foremost depends on the quality of the GPS receiver. 2D accuracy (95%) - approximately 0.76 m - was obtained in Prague and its surroundings. Deutsche Telecomm did experiments on the Baltic coast, and reported that accuracy was about 6 meters.

Access restriction

Copyright

fullscreen: International cooperation and technology transfer

Monograph

Chapter

Table of contents

Cite and reuse

Monograph

Chapter

Image

Image fragment

Citation links

Citation recommendation