R/V Atlantis Athena metadata file
Thu 19/Sep/2002 12:42:59

True wind speed & direction (TWind)
  Format:   Speed, Direction  (meters/sec, degrees)
  Wind direction is given in meteorological terms; a 0 degree wind comes from
   the north.  Ship speed and direction of travel are obtaned from GPS data
  (GGA SOG & COG).  Sensor mounting orientation is corrected using the
  direction the ship is pointing obtained from the gyro (the ship is not necessarily
  moving in the direction its pointing).  

True wind speed (Wnd_Spd)
  Format:  Wnd_spd  (meters/sec)
  Wind speed obtained from the IMET wind sensor and corrected for ship heading
  (gyro) plus ship course and speed (GPS SOG & COG).


True wind direction (Wnd_Dir)
  Format:  Wnd_dir  (degrees)
  Wind direction obtained from the IMET wind sensor and corrected for ship
   heading (gyro) plus ship course and speed (GPS SOG & COG).

Sound velocity  ( SSV)
  Format:  Sound_Velocity  (meters/sec)
  Surface sound velocity calculated from sea surface temperature and
  conductivity data values.  Intermediate salinity values are calculated in
  accordance with UNESCO 44.

Salinity (Salinity)
  Format:  Salinity
  Salinity calculated from sea surface temperature and conductivity data values
  in accordance with UNESCO 44.


IMET Precipation (IMET_PRC)
  Format:  Precipitation (millimeters)

Sea Surface Temperature (SSTMP)
  Falmouth Scientific TSG (OTM-S-212) sea surface conductivity (degrees C)
  Format:     Sea surface temperature
  OTM sensor is mounted in the bow thruster room on the suction side of the clean
  sea water distribution pump.  Sea water intake is from a bow sea chest located
  12 feet below the waterline.

IMET Wind (IMET_WND)
  Format: X, Y, Total, Max, Min, LastVane, LastCompass, C1, C2

	Wind X (m/sec), Positive for a stbd to port wind
	Wind Y (m/sec), Positive for a bow to stern wind
	Wind Total (m/sec), Averaged over previous minute
	Wind Max (m/sec, 15 sec interval),
	Wind Min (m/sec, 15 sec interval),
	Last Vane Reading (deg),
	Last Compass Reading (deg),
	Counter1 ("0"), Counter2 ("4")
	
	Note - Wind direction is not provided as a
	  single quantity.  Direction values are ship relative.
	  The wind sensor does not have a compass installed
	  (value should always be 0.0).


IMET relative humidity (HRH)
  Format:   Humidity (%RH)
  Data is obtained from IMET_HRH primary sensor.

IMET Humidity (IMET_HRH)
   Format:  Humidity (%RH), Temperature (C)
   Note - IMET humidity and air temperature data are both obtained from this instrument.


IMET Shortwave Radiation (IMET_SWR)
  Format:  Radiation (watts/square meter)

IMET Barometric Pressure (IMET_BPR)
  Format:  Barometric pressure (milli-bars)

IMET Air Temperature (Air_Temp)
  Format: Temp (C)
  Data is obtained from IMET_HRH primary sensor.

Sea Surface Conductivity (SSCND)
  Falmouth Scientific TSG (OCM-S-212) sea surface conductivity (mmho/cm)
  Format:   Conductivity
  OCM sensor is mounted in the bow thruster room on the suction side of the clean
   sea water distribution pump.  Sea water intake is from a bow sea chest located
  12 feet below the waterline.

GPS type (GPS_TYPE)
  GPS position type (Std, Diff, P-Code)
  GPS position type indicator is obtained from the "quality indicator" included
  as part of the GPS NMEA GGA data sentence.

NMEA Gyro (HEHDT)
  Ship's heading obtained from the Sperry Gyro.
  NMEA format:  Header ($HEHDT), Heading (degrees), T (true),
  Heading (degrees), M (magnetic) * checksum.

  Version 2.20 (1/1/97) of the NMEA 0183 standard does not show magnetic
   heading in this data sentence and the validity of this item is questionable.

Gyro heading (Gyro)
  Ship's heading (degrees true) obtained from the Gyro NMEA HEHDT data
  sentence.
  Format:   Heading  (degrees true)

GPS Navigation data (GPS)
  Complete NMEA data output from the primary GPS receiver.
  The datum used by both the P-Code and Northstar GPS receivers is WGS84.

  The single digit following the position information in the GPS_GGA data string
   indicates the type of GPS fix as follows:
      0=No valid fix; 1=Standard; 2=Differential; 3=P-Code

  NMEA GPS_GGA data sentence:  Header , UTC of position, Latitude, N/S,
  Longitude, E/W, Quality indicator, Number of satellites in use, Horizontal dilution,
  Altitude, M (meters),  Geoidal seperation, M (meters), Age of differential data
  (secs), Differential reference station I.D. * checksum.
  (Lat & Lon values are "degrees minutes.decimal_minutes") 

  NMEA GPS-VTG data sentence:  Header, Course, T (degrees true),
  Course, M (magnetic), Speed, N (knots), Speed, K (km/hr) * checksum.

Position from GPS receiver (Lat_Lon)
  Latitude & Longitude in decimal degrees.
  Format:  +/-dd.dddddd  +/-ddd.dddddd
  (N & E are "+")

GPS speed over ground (GPS_SOG)
  Speed over ground (knots) obtained from NMEA GPS_VTG data sentence.
  Format:  Speed


GPS course over ground (GPS_COG)
  Course over ground (true) obtained from NMEA GPS_VTG data sentence.
  Format:  Course

Latitude (GPS_Lat)
  Latitude from GPS NMEA GGA data sentence formatted for display.
  Format:  dd mm.mmm, N/S

Longitude (GPS_Lon)
  Longitude from GPS NMEA GGA data sentence formatted for display.
  Format:  ddd mm.mmm, E/W