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NAVIGATION AND DATA ACQUISITION

The vessel was set-up for multibeam data acquisition and navigation with RESON PDS-2000. A workstation was used for the acquisition of (PDS-2000) multibeam data, interfacing by a multiserial and Ethernet link a RESON 8160 P1 processor, an IXEA OCTANS compass, DGPS receiver, by a MOXA Multi/serial I/O, TCP/IP and UDP network sockets.

The MBES was the 50kHz, 126 0.5°, 150°aperture RESON 8160 (5000 m range). The sonar head is positioned on the ship's keel using a low-angle V-shaped steel frame. A sound velocity probe at the Sonar Head is interfaced directly to the MBES processor, thus providing the necessary real-time data for the beam-forming.

The datum WGS84 and the UTM, zone 33, were chosen for navigation and display purposes. Timing was set to UTC for data acquisition. The PDS-2000 production DTM was set to grid sizes ranging from 20 to 25m. The DELPH Seismic SBP-CHIRP workstation received positions trough an NMEA sentence by the DGPS receiver. The positions were therefore recorded on the trace headers as Easting/Northing of the DGPS antenna. An ISMAR's Marine Magnetics SeaSpy Magnetometer tow fish was towed 120m (point STERN-LEFT), on the port side. An INGV's Geometrics G-811 Gradiometer system was towed 150-300m astern, on the starboard side. A gravimeter was installed very close to the center of gravity of ship.

Fig.6 shows the consoles of the main recording instruments on the recording and navigation room.

figure

Figure 6: Recording room on R/V Universitatis 
\begin{figure}\centerline{\epsfig{file=IMG/INSTRUMENTS.ps,width=17.5cm}}
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The instrumental offsets (PDS-2000) are presented in Fig. 7 and in Tab. 3.


Table 3: Instrumental Offsets on R/V Universitatis (PDS2000). The GPS antenna (primary positioning system) is located on point DGPS.
POSITION ACROSS ALONG HEIGHT
REFERENCE 0.00 0.00 0.00
DGPS 1.55 11.85 12.45
MBEAM 0.00 11.45 -3.84
OCTANS 0.00 0.0 0.25
SBE-911 5.00 -5.00 0.00
EA-400 0.00 11.45 -3.84
CHIRP -1.60 5.25 -3.80
STERN 0.00 -21 0.00
STERN-LEFT -4.38 -21.0 0.0
STERN-RIGHT 4.38 -21.0 0.0
GRAVIMETER 0.5 0.5 -1.0


figure

Figure 7: Cruise MRS06. Instrumental Offsets (PDS-2000) on R/V Universitatis 
\begin{figure}\centerline{\epsfig{file=IMG/MRS06_UNIVERSITATIS_OFFSETS.eps,width=15cm}}
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next up previous contents
Next: MULTIBEAM BATHYMETRY AND BACKSCATTER Up: MATERIALS AND METHODS Previous: MATERIALS AND METHODS   Contents
2006-11-01