The project had participants from these institutions:
The survey was conducted from May 20 to June 30, 2003, onboard University of Bergen research vessel RV Håkon Mosby. Pictures can be found here ... Content
1. Data, log files, format descriptions1.1 Data and log files
Table 1: Data, log files
1.2 Format description Survey Computer (EIVA) log files:Shot (= Event) files; format example:
Table 2. Shot (event) file format description.
|
06:21:59 23.05.2003; 553674.1175;6744618.7726; 060°49.995410'; 003°59.234563'; 326.2000; 12008.8500; 50667.0000 |
Field no. | Example | Parameter | Notes |
---|---|---|---|
1 | 06:21:59 | Time | Survey computer time not accurate - could differ by more then 10 seconds from UTC. |
2 | 23.05.2003 | Date | |
3 | 553674.1175 | UTM Easting | Refered to position of crane used to deploy the OBS. |
4 | 6744618.7726 | UTM Northing | Refered to position of crane used to deploy the OBS. |
5 | 060°49.995410' | Latitude | |
6 | 003°59.234563' | Longitude | |
7 | 326.2000 | Depth | From EK500 Echo Sounder |
8 | 12008.8500 | Gravity | (check - filtered, raw??) |
9 | 50667.0000 | Magnetometer | (Length of mag tow fish cable - check!) |
Table 3. 10 second interval log file format description.
=================== Event 00001 Wednesday, June 11, 2003 07:47:27 MANUAL =================== Message: OBS72 Cycle at 0.740 Gyro 320.35 Roll 0.00 Pitch 0.00 Heave 0.00 SOG 0.08 COG 63.78 LOP Code System Measurement Converted Error Wgt -------------------------------------------------------------------------------- 0 1 GPS1 (NMEA): Seapath 558940.057 558940.081 0.152 1.00 1 1 GPS1 (NMEA): Seapath 7640272.663 7640272.614 -7.836 1.00 2 1 GPS2 (NMEA): Trimble 558933.681 558933.768 0.918 1.00 3 1 GPS2 (NMEA): Trimble 7640292.477 7640293.055 2.864 1.00 4 1 Gyro: User Defined g 320.350 318.984 315.637 0.00 Position Easting Northing Height S.td Data --------------------------------------------------------------------------------- 1 : 558940.410 7640277.937 0.00 5.36 Filtered : 558939.738 7640277.812 0.00 -1.00 - Kran : 558937.809 7640273.477 0.00 0.00 - EK500 : 558934.193 7640279.616 -1.00 0.12 D 2995.50 B 1.00 input 1: : 559071.664 7640127.033 0.00 0.72 D 56013.00 B 0.00 input 2: : 558940.410 7640277.937 0.00 0.39 D 12534.17 B 0.00 |
Some navigation related abbreviations: LOP = line of position, SOG = speed over ground, COG = course over ground.
The LOP's listed (0..4) are the positioning devices used in UTM coordinate calculation. Data from each unit has a certain weight (Wgt) in the calculation.
The OBS is deployed from a crane; it's position is given in the "Kran" line.
EK500 is depth data, input 1 is magnetometer data (not valid as it is not in operation during OBS deployment) and input 2 is gravitymeter data (should be discarded, like mag data).
Click on image below to download pdf version.
Fig 2: Airgun source layout, signature, spectrum. Click to download pdf version. Software used: NUCLEUS, by PGS.
Ashtech GPS had to be reconfigured at start of survey. Use the Ashtech Evaluate program - there are two directories, "evaluate1" that holds unzipped main file, ready to be installed, and "Ashtech Evaluate" that is copied from already installed version (the latter may or may not work if it is just copied to a new PC).
Send these commands to the GPS (a modified version of this config file):
Command | Description |
---|---|
$PASHS,RST | Reset with default settings |
$PASHS,SYS,MIX | Set receiver in mixed GPS/GLONASS mode |
$PASHS,PEM,5 | Set elevation mask to 5 degrees |
$PASHS,NME,RMC,C,ON | Send NMEA message RMC on port C |
$PASHS,NME,PER,1.0 | Set NMEA "send message interval" to 1 Hz |
$PASHS,PHE,F | Set event marker signal to falling edge |
$PASHS,PPS,01.00,+000.0000,F | Set 1PPS trigger edge to falling edge |
$PASHS,NME,TTT,B,ON | Output Event marker message on port B |
$PASHS,TSC,GPS | Output Event marker time in GPS-system-time |
$PASHS,SAV,Y | Save settings in battery backed-up memory |
If this GPS should fail: Use the GUNSTAMP system (ask Trond S.).
This terminal program permits 600 bits/second datarate, this is not common in other terminal programs. It's here.
The map showing ship's position and past 24 hour trackline is updated every minute. The weather station graphs are updated every 10 min. The web page itself is refreshed every 30 sec. More information on this software: