Geoscience Reference
In-Depth Information
Fig. 3
Distribution of ISKANDARnet reference stations (as modified in Google Maps)
4 Real-Time GPS Data Streaming Using NTRIP Protocol
Ntrip protocol is used for the real-time GPS data streaming in this study. Ntrip (see
Fig.
4
) basically consists of the following components (Weber et al.
2006
):
(a) NtripSources generate continuous raw GPS data streams. Each GPS data
sources are recognized by a unique identifier called mount-point.
(b) NtripServers transfer raw GPS data stream of an NtripSource to the Ntrip-
Caster or control centre.
(c) NtripCaster provides security for the service providers and facilitates the
accessibility of data to multiple users. The administrator of the NtripCaster
organizes all available NtripSources and defines all source identifiers
(mountpoints), port number, and user passwords. Source-table containing
information on stations and data streams is also managed by NtripCaster. The
control centre and NtripCaster used for this study are located at GNSS and
Geodynamics Laboratory, Universiti Teknologi Malaysia.
(d) NtripClient receives final position solution from the NtripCaster or control
centre.
In this study, the Ntrip protocol was utilized to test the RRTK algorithm (see
Fig.
5
) by streaming raw GPS data from both the reference and roving stations to
the control centre for processing, and transmission of the position solution to the
