Interpreting NMEA data

$PAMTS… is a depth sentence – not relevant for us but on by default.

($P indicates proprietary code).

$YX indicates “Transducer”

$YXXDR(T).. gives Airmar sensor board temp and voltage which should not be enabled by default.

$YXXDR(B)… gives vessel attitude and is on by default

$IIMWV… is the LCJ Capteurs CV7 “wind” sentence. II stands for integrated instrumentation, MWV for acoustic wind sensor. The format is as follows:-

$IIMWV,318.0,R,014.8,N,A*3A

1)      is the wind direction in degrees, (318.0)

2)      R = relative or apparent wind,

3)      wind speed, (014.8)

4)      N = knots, it can be K/M/N (Kilometres/hr, M/s, knots)

5)      A indicates the CV7 status, “A” is a correct measure,V is an incorrect measure,

6)      3D is a checksum.

$WIXDR… is  the “Wind temperature” sentence from the CV7 sensor. The format is:-

$WIXDR,C,017.0,C,,*54 

1)      “017.0” is the temperature with one decimal place,

2)      C = the temperature scale (Centigrade),

3)       54 is a checksum.

$VMNLA… gives Nautical Leeway angle

$VWVHW… gives Speed through water VW indicates “Velocity sensor, speed log, water, mechanical

$GP…. Indicates GPS data.

$GPVWR gives Relative wind speed and angle. The format is:-

$GPVWR,42.00,L,14.80,N,7.61,M,27.41,K*7B

1)      Wind direction magnitude in degrees

2)      Wind direction Left/Right of Bow

3)      Speed

4)      N = Knots

5)      Speed

6)      M = metres/sec

7)      Speed

8)      K = Kilometres/hr

9)      Checksum

$GPMWV gives Wind speed and angle, the details are as for $IIMWV above

$GPVHW gives Water speed and heading. The format is:-

$GPVHW,,,,,4.79,N,8.87,K*56

1)      heading in degrees True

2)      T = True

3)      Heading in degrees Magnetic

4)      M = Magnetic

5)      speed (4.79) in knots,

6)      N = knots

7)      Speed relative to water in Kilometers/hr,

8)      K = kilometres,

9)      checksum.

 Here is a sample output from the multiplexer:-

$GPVWR,42.00,L,14.80,N,7.61,M,27.41,K*7B                       GPS or MX wind sentence

$GPMWV,318.00,R,14.80,N,A*1D                                             GPS wind speed and angle

$IIMWV,318.0,R,014.8,N,A*3A                                                  Wind sentence

$WIXDR,C,017.0,C,,*54                                                                  Wind or air temperature

$GPVHW,,,,,4.79,N,8.87,K*56                                                      GPS water speed & heading

$GPVLW,32.75,N,22.15,N,*71                                                     GPS log distance

$VMVHW,,,,,4.79,N,8.86,K*5B                                                     Water speed sentence

$VMNLA,-1.1,A*1A                                                                          Leeway sentence

$GPVWR,42.00,L,14.90,N,7.67,M,27.59,K*75

$GPMWV,318.00,R,14.90,N,A*1C

$IIMWV,318.0,R,014.9,N,A*3B

$WIXDR,C,017.0,C,,*54

$VMNLA,-1.5,A*1E

$GPVWR,42.00,L,14.90,N,7.67,M,27.59,K*75

$GPMWV,318.00,R,14.90,N,A*1C

$IIMWV,318.0,R,014.9,N,A*3B

$WIXDR,C,017.0,C,,*54

$VMNLA,-1.8,A*13

$GPVWR,44.00,L,14.80,N,7.61,M,27.41,K*7D

$GPMWV,316.00,R,14.80,N,A*13

$IIMWV,316.0,R,014.8,N,A*34

$WIXDR,C,017.0,C,,*54

$VMNLA,-1.8,A*13

$GPVWR,43.00,L,14.90,N,7.67,M,27.59,K*74

$GPMWV,317.00,R,14.90,N,A*13

$IIMWV,317.0,R,014.9,N,A*34

$WIXDR,C,017.0,C,,*54

$YXXDR,A,-6.5,D,PTCH,A,4.7,D,ROLL*70

$GPVWR,43.00,L,15.00,N,7.72,M,27.78,K*7B

$GPMWV,317.00,R,15.00,N,A*1B

Some standard GPS NMEA sentences taken from aprs.gids.nl/nmea/#allgp:

• $GPAAM - Waypoint Arrival Alarm
• $GPALM - GPS Almanac Data
• $GPAPA - Autopilot Sentence "A"
• $GPAPB - Autopilot Sentence "B"
• $GPASD - Autopilot System Data
• $GPBEC - Bearing & Distance to Waypoint, Dead Reckoning
• $GPBOD - Bearing, Origin to Destination
• $GPBWC - Bearing & Distance to Waypoint, Great Circle
• $GPBWR - Bearing & Distance to Waypoint, Rhumb Line
• $GPBWW - Bearing, Waypoint to Waypoint
• $GPDBT - Depth Below Transducer
• $GPDCN - Decca Position
• $GPDPT - Depth
• $GPFSI - Frequency Set Information
• $GPGGA - Global Positioning System Fix Data
• $GPGLC - Geographic Position, Loran-C
• $GPGLL - Geographic Position, Latitude/Longitude
• $GPGSA - GPS DOP and Active Satellites
• $GPGSV - GPS Satellites in View
• $GPGXA - TRANSIT Position
• $GPHDG - Heading, Deviation & Variation
• $GPHDT - Heading, True
• $GPHSC - Heading Steering Command
• $GPLCD - Loran-C Signal Data
• $GPMTA - Air Temperature (to be phased out)
• $GPMTW - Water Temperature
• $GPMWD - Wind Direction
• $GPMWV - Wind Speed and Angle
• $GPOLN - Omega Lane Numbers
• $GPOSD - Own Ship Data
• $GPR00 - Waypoint active route (not standard)
• $GPRMA - Recommended Minimum Specific Loran-C Data
• $GPRMB - Recommended Minimum Navigation Information
• $GPRMC - Recommended Minimum Specific GPS/TRANSIT Data
• $GPROT - Rate of Turn
• $GPRPM - Revolutions
• $GPRSA - Rudder Sensor Angle
• $GPRSD - RADAR System Data
• $GPRTE - Routes
• $GPSFI - Scanning Frequency Information
• $GPSTN - Multiple Data ID
• $GPTRF - Transit Fix Data
• $GPTTM - Tracked Target Message
• $GPVBW - Dual Ground/Water Speed
• $GPVDR - Set and Drift
• $GPVHW - Water Speed and Heading
• $GPVLW - Distance Traveled through the Water
• $GPVPW - Speed, Measured Parallel to Wind
• $GPVTG - Track Made Good and Ground Speed
• $GPWCV - Waypoint Closure Velocity
• $GPWNC - Distance, Waypoint to Waypoint
• $GPWPL - Waypoint Location
• $GPXDR - Transducer Measurements
• $GPXTE - Cross-Track Error, Measured
• $GPXTR - Cross-Track Error, Dead Reckoning
• $GPZDA - Time & Date
• $GPZFO - UTC & Time from Origin Waypoint
• $GPZTG - UTC & Time to Destination Waypoint
• $GPOLN - Omega Lane Numbers
• $GPOSD - Own Ship Data
• $GPR00 - Waypoint active route (not standard)
• $GPRMA - Recommended Minimum Specific Loran-C Data
• $GPRMB - Recommended Minimum Navigation Information
• $GPRMC - Recommended Minimum Specific GPS/TRANSIT Data
• $GPROT - Rate of Turn
• $GPRPM - Revolutions
• $GPRSA - Rudder Sensor Angle
• $GPRSD - RADAR System Data
• $GPRTE - Routes
• $GPSFI - Scanning Frequency Information
• $GPSTN - Multiple Data ID
• $GPTRF - Transit Fix Data
• $GPTTM - Tracked Target Message
• $GPVBW - Dual Ground/Water Speed
• $GPVDR - Set and Drift
• $GPVHW - Water Speed and Heading
• $GPVLW - Distance Traveled through the Water
• $GPVPW - Speed, Measured Parallel to Wind
• $GPVTG - Track Made Good and Ground Speed
• $GPWCV - Waypoint Closure Velocity
• $GPWNC - Distance, Waypoint to Waypoint
• $GPWPL - Waypoint Location
• $GPXDR - Transducer Measurements
• $GPXTE - Cross-Track Error, Measured
• $GPXTR - Cross-Track Error, Dead Reckoning
• $GPZDA - Time & Date
• $GPZFO - UTC & Time from Origin Waypoint
• $GPZTG - UTC & Time to Destination Waypoint

Can use NavMonPc advanced routing to select which NMEA messages are used, but need to have sensors and Mux running and outputting NMEA sentences so that they can be “collected”. (See p44 -48 of NavMonPc user manual).