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	Title Petrobar-2007 Survey Notes on instrumentation support
	By O.M.	Date 27 Nov 2012	Version 0.1

Click to see photo album.

Offset distances

• EIVA Survey Computer offset is such that positions are referred to ship's Center of Gravity (CG).
• Guns: 64 meter behind ship's CG.

Navigation data, logs, GPS timestamp of shot events

Ashtech "GG24" GPS - Time stamp of shotpoints

NOTE:

• Time is GPS-time. As of 16 August 2007, GPS time is 14 seconds ahead of UTC time.
• Files contain two types of data:
  • NMEA GPGGA sentences, every 10 seconds. The number of satellites used can be monitored.
  • Time stamps. Example:
    $PASHR,TTT,2,21:59:03.5468332*0D

Sonobuoys

The Sonobuoy receiver system consists of these parts:

1. Antenna:
   • Mfr.: Vårgårda
   • Model: 3EL2
   • Supplier: Permo Electronics
2. Radio receivers
   These receivers are ordered from Greenridge Sciences. They modify the low-frequency properties so that bandwidth is extended down to 5 Hz (- 3dB).
   • Mfr: ICOM
   • Model: PCR1500
     Modified, calibrated sonobuoy radio receiver
     Lower -3dB frequency cut-off: 5 Hz
     Upper -3dB frequency cut-off: 20 kHz
   • Supplier: Greeneridge Science, Inc.
3. Antenna pre-amplifier:
   • Model: P160-175VDG-C
     Preamplifier, receive only, 160-175MHz, w/BNC connectors, w/choke (powered via coax), packaged in a watertight container for mounting near antenna.
   • Supplier: Greeneridge Science, Inc.
4. DC-Injector, for antenna preamplifier
   • Model: 3 DC-INJ-B
     DC Injector Bias 'T', w/BNC connectors. Pair of banana jacks to accept 10-16 VDC from user supplied power supply.
   • Supplier: Greeneridge Sciences, Inc.
5. Software for tuning and controlling multiple radios from a single window
   • Supplier: Greeneridge Sciences, Inc.

TIPS: Two receivers can be operated at the same time on a Win XP computer, by starting a separate session in two different user accounts.