AAM - Waypoint Arrival Alarm

        1 2 3   4 5    6
        | | |   | |    |
 $--AAM,A,A,x.x,N,c--c*hh<CR><LF>

 Field Number: 
 1) Status, BOOLEAN, A = Arrival circle entered
 2) Status, BOOLEAN, A = perpendicular passed at waypoint
 3) Arrival circle radius
 4) Units of radius, nautical miles
 5) Waypoint ID
 6) Checksum

 ALM - GPS Almanac Data

        1   2   3  4   5  6    7  8    9    10     11     12     13     14  15   16
        |   |   |  |   |  |    |  |    |    |      |      |      |      |   |    |
 $--ALM,x.x,x.x,xx,x.x,hh,hhhh,hh,hhhh,hhhh,hhhhhh,hhhhhh,hhhhhh,hhhhhh,hhh,hhh,*hh<CR><LF>

 Field Number: 
  1) Total number of messages
  2) Message Number
  3) Satellite PRN number (01 to 32)
  4) GPS Week Number :
	Date and time in GPS is computed as number of weeks from 6 January 1980 plus
     	number of seconds into the week.
  5) SV health, bits 17-24 of each almanac page
  6) Eccentricity
  7) Almanac Reference Time
  8) Inclination Angle
  9) Rate of Right Ascension
 10) Root of semi-major axis
 11) Argument of perigee
 12) Longitude of ascension node
 13) Mean anomaly
 14) F0 Clock Parameter
 15) F1 Clock Parameter
 16) Checksum

 APA - Autopilot Sentence "A"

        1 2  3   4 5 6 7  8  9 10    11
        | |  |   | | | |  |  | |     |
 $--APA,A,A,x.xx,L,N,A,A,xxx,M,c---c*hh<CR><LF>

 Field Number: 
  1) Status
     V = LORAN-C Blink or SNR warning
     V = general warning flag or other navigation systems when a reliable
         fix is not available
  2) Status
     V = Loran-C Cycle Lock warning flag
     A = OK or not used

  3) Cross Track Error Magnitude
  4) Direction to steer, L or R
  5) Cross Track Units (Nautic miles or kilometers)
  6) Status
     A = Arrival Circle Entered
  7) Status
     A = Perpendicular passed at waypoint
  8) Bearing origin to destination
  9) M = Magnetic, T = True
 10) Destination Waypoint ID
 11) checksum

 APB - Autopilot Sentence "B"
                                         13    15
        1 2 3   4 5 6 7 8   9 10   11  12|   14|
        | | |   | | | | |   | |    |   | |   | |
 $--APB,A,A,x.x,a,N,A,A,x.x,a,c--c,x.x,a,x.x,a*hh<CR><LF>

 Field Number: 
  1) Status
     V = LORAN-C Blink or SNR warning
     V = general warning flag or other navigation systems when a reliable
         fix is not available
  2) Status
     V = Loran-C Cycle Lock warning flag
     A = OK or not used
  3) Cross Track Error Magnitude
  4) Direction to steer, L or R
  5) Cross Track Units, N = Nautical Miles
  6) Status
     A = Arrival Circle Entered
  7) Status
     A = Perpendicular passed at waypoint
  8) Bearing origin to destination
  9) M = Magnetic, T = True
 10) Destination Waypoint ID
 11) Bearing, present position to Destination
 12) M = Magnetic, T = True
 13) Heading to steer to destination waypoint
 14) M = Magnetic, T = True
 15) Checksum

 ASD - Autopilot System Data
 FORMAT UNKOWN

 BEC - Bearing & Distance to Waypoint - Dead Reckoning
                                                         12
        1         2       3 4        5 6   7 8   9 10  11|    13
        |         |       | |        | |   | |   | |   | |    |
 $--BEC,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh<CR><LF>

 Field Number: 
  1) UTCTime
  2) Waypoint Latitude
  3) N = North, S = South
  4) Waypoint Longitude
  5) E = East, W = West
  6) Bearing, True
  7) T = True
  8) Bearing, Magnetic
  9) M = Magnetic
 10) Nautical Miles
 11) N = Nautical Miles
 12) Waypoint ID
 13) Checksum


 BOD - Bearing - Waypoint to Waypoint

        1   2 3   4 5    6    7
        |   | |   | |    |    |
 $--BOD,x.x,T,x.x,M,c--c,c--c*hh<CR><LF>

 Field Number: 
  1) Bearing Degrees, TRUE
  2) T = True
  3) Bearing Degrees, Magnetic
  4) M = Magnetic
  5) TO Waypoint
  6) FROM Waypoint
  7) Checksum

 BWC - Bearing and Distance to Waypoint
 Latitude, N/S, Longitude, E/W, UTC, Status
                                                       11
        1         2       3 4        5 6   7 8   9 10  | 12   13
        |         |       | |        | |   | |   | |   | |    |
 $--BWC,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh<CR><LF>

 Field Number: 
  1) UTCTime
  2) Waypoint Latitude
  3) N = North, S = South
  4) Waypoint Longitude
  5) E = East, W = West
  6) Bearing, True
  7) T = True
  8) Bearing, Magnetic
  9) M = Magnetic
 10) Nautical Miles
 11) N = Nautical Miles
 12) Waypoint ID
 13) Checksum

 BWR - Bearing and Distance to Waypoint - Rhumb Line
 Latitude, N/S, Longitude, E/W, UTC, Status
                                                       11
        1         2       3 4        5 6   7 8   9 10  | 12   13
        |         |       | |        | |   | |   | |   | |    |
 $--BWR,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh<CR><LF>

 Field Number: 
  1) UTCTime
  2) Waypoint Latitude
  3) N = North, S = South
  4) Waypoint Longitude
  5) E = East, W = West
  6) Bearing, True
  7) T = True
  8) Bearing, Magnetic
  9) M = Magnetic
 10) Nautical Miles
 11) N = Nautical Miles
 12) Waypoint ID
 13) Checksum

 BWW - Bearing - Waypoint to Waypoint

        1   2 3   4 5    6    7
        |   | |   | |    |    |
 $--BWW,x.x,T,x.x,M,c--c,c--c*hh<CR><LF>

 Field Number: 
  1) Bearing Degrees, TRUE
  2) T = True
  3) Bearing Degrees, Magnetic
  4) M = Magnetic
  5) TO Waypoint
  6) FROM Waypoint
  7) Checksum

 DBK - Depth Below Keel

        1   2 3   4 5   6 7
        |   | |   | |   | |
 $--DBK,x.x,f,x.x,M,x.x,F*hh<CR><LF>

 Field Number: 
  1) Depth, feet
  2) f = feet
  3) Depth, meters
  4) M = meters
  5) Depth, Fathoms
  6) F = Fathoms
  7) Checksum

 DBS - Depth Below Surface

        1   2 3   4 5   6 7
        |   | |   | |   | |
 $--DBS,x.x,f,x.x,M,x.x,F*hh<CR><LF>

 Field Number: 
  1) Depth, feet
  2) f = feet
  3) Depth, meters
  4) M = meters
  5) Depth, Fathoms
  6) F = Fathoms
  7) Checksum

 DBT - Depth below transducer

        1   2 3   4 5   6 7
        |   | |   | |   | |
 $--DBT,x.x,f,x.x,M,x.x,F*hh<CR><LF>

 Field Number: 
  1) Depth, feet
  2) f = feet
  3) Depth, meters
  4) M = meters
  5) Depth, Fathoms
  6) F = Fathoms
  7) Checksum

 DCN - Decca Position
                                      11  13      16
        1  2  3   4 5  6   7 8  9   10| 12| 14  15| 17
        |  |  |   | |  |   | |  |   | | | | |   | | |
 $--DCN,xx,cc,x.x,A,cc,x.x,A,cc,x.x,A,A,A,A,x.x,N,x*hh<CR><LF>

 Field Number: 
  1) Decca chain identifier
  2) Red Zone Identifier
  3) Red Line Of Position
  4) Red Master Line Status
  5) Green Zone Identifier
  6) Green Line Of Position
  7) Green Master Line Status
  8) Purple Zone Identifier
  9) Purple Line Of Position
 10) Purple Master Line Status
 11) Red Line Navigation Use
 12) Green Line Navigation Use
 13) Purple Line Navigation Use
 14) Position Uncertainity
 15) N = Nautical Miles
 16) Fix Data Basis
     1 = Normal Pattern
     2 = Lane Identification Pattern
     3 = Lane Identification Transmissions
 17) Checksum

 DPT - Heading - Deviation & Variation

        1   2   3
        |   |   |
 $--DPT,x.x,x.x*hh<CR><LF>

 Field Number: 
  1) Depth, meters
  2) Offset from transducer, 
     positive means distance from tansducer to water line
     negative means distance from transducer to keel
  3) Checksum

 FSI - Frequency Set Information

        1      2      3 4 5
        |      |      | | |
 $--FSI,xxxxxx,xxxxxx,c,x*hh<CR><LF>

 Field Number: 
  1) Transmitting Frequency
  2) Receiving Frequency
  3) Communications Mode (NMEA Syntax 2)
  4) Power Level
  5) Checksum

 GGA - Global Positioning System Fix Data
 Time, Position and fix related data fora GPS receiver.

                                                      11
        1         2       3 4        5 6 7  8   9  10 |  12 13  14   15
        |         |       | |        | | |  |   |   | |   | |   |    |
 $--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh<CR><LF>

 Field Number: 
  1) Universal Time Coordinated (UTC)
  2) Latitude
  3) N or S (North or South)
  4) Longitude
  5) E or W (East or West)
  6) GPS Quality Indicator,
     0 - fix not available,
     1 - GPS fix,
     2 - Differential GPS fix
  7) Number of satellites in view, 00 - 12
  8) Horizontal Dilution of precision
  9) Antenna Altitude above/below mean-sea-level (geoid) 
 10) Units of antenna altitude, meters
 11) Geoidal separation, the difference between the WGS-84 earth
     ellipsoid and mean-sea-level (geoid), "-" means mean-sea-level
     below ellipsoid
 12) Units of geoidal separation, meters
 13) Age of differential GPS data, time in seconds since last SC104
     type 1 or 9 update, null field when DGPS is not used
 14) Differential reference station ID, 0000-1023
 15) Checksum

 GLC - Geographic Position, Loran-C
                                           12    14
        1    2   3 4   5 6   7 8   9 10  11|   13|
        |    |   | |   | |   | |   | |   | |   | |
 $--GLC,xxxx,x.x,a,x.x,a,x.x,a.x,x,a,x.x,a,x.x,a*hh<CR><LF>

 Field Number: 
  1) GRI Microseconds/10
  2) Master TOA Microseconds
  3) Master TOA Signal Status
  4) Time Difference 1 Microseconds
  5) Time Difference 1 Signal Status
  6) Time Difference 2 Microseconds
  7) Time Difference 2 Signal Status
  8) Time Difference 3 Microseconds
  9) Time Difference 3 Signal Status
 10) Time Difference 4 Microseconds
 11) Time Difference 4 Signal Status
 12) Time Difference 5 Microseconds
 13) Time Difference 5 Signal Status
 14) Checksum

 GLL - Geographic Position - Latitude/Longitude

	1       2 3        4 5         6 7
	|       | |        | |         | |
 $--GLL,llll.ll,a,yyyyy.yy,a,hhmmss.ss,A*hh<CR><LF>

 Field Number: 
  1) Latitude
  2) N or S (North or South)
  3) Longitude
  4) E or W (East or West)
  5) Universal Time Coordinated (UTC)
  6) Status A - Data Valid, V - Data Invalid
  7) Checksum

 GSA - GPS DOP and active satellites

	1 2 3                        14 15  16  17  18
	| | |                         |  |   |   |   |
 $--GSA,a,a,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x.x,x.x,x.x*hh<CR><LF>

 Field Number: 
  1) Selection mode
  2) Mode
  3) ID of 1st satellite used for fix
  4) ID of 2nd satellite used for fix
  ...
  14) ID of 12th satellite used for fix
  15) PDOP in meters
  16) HDOP in meters
  17) VDOP in meters
  18) checksum

 GSV - Satellites in view

	1 2 3 4 5 6 7     n
	| | | | | | |     |
 $--GSV,x,x,x,x,x,x,x,...*hh<CR><LF>

 Field Number: 
  1) total number of messages
  2) message number
  3) satellites in view
  4) satellite number
  5) elevation in degrees
  6) azimuth in degrees to true
  7) SNR in dB
  more satellite infos like 4)-7)
  n) checksum

 GTD - Geographic Location in Time Differences

 	 1   2   3   4   5  6
	 |   |   |   |   |  |
 $--GTD,x.x,x.x,x.x,x.x,x.x*hh<CR><LF>

 Field Number: 
  1) time difference
  2) time difference
  3) time difference
  4) time difference
  5) time difference
  n) checksum

 GXA - TRANSIT Position - Latitude/Longitude
 Location and time of TRANSIT fix at waypoint

        1         2       3 4        5 6    7 8
        |         |       | |        | |    | |
 $--GXA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,c--c,X*hh<CR><LF>

 Field Number: 
 1) UTC of position fix
 2) Latitude
 3) East or West
 4) Longitude
 5) North or South
 6) Waypoint ID
 7) Satelite number
 8) Checksum

 HDG - Heading - Deviation & Variation

        1   2   3 4   5 6
        |   |   | |   | |
 $--HDG,x.x,x.x,a,x.x,a*hh<CR><LF>

 Field Number: 
  1) Magnetic Sensor heading in degrees
  2) Magnetic Deviation, degrees
  3) Magnetic Deviation direction, E = Easterly, W = Westerly
  4) Magnetic Variation degrees
  5) Magnetic Variation direction, E = Easterly, W = Westerly
  6) Checksum

 HDM - Heading - Magnetic

        1   2 3
        |   | |
 $--HDM,x.x,M*hh<CR><LF>

 Field Number: 
  1) Heading Degrees, magnetic
  2) M = magnetic
  3) Checksum

 HDT - Heading - True

        1   2 3
        |   | |
 $--HDT,x.x,T*hh<CR><LF>

 Field Number: 
  1) Heading Degrees, true
  2) T = True
  3) Checksum

 HSC - Heading Steering Command

        1   2 3   4  5
        |   | |   |  |
 $--HSC,x.x,T,x.x,M,*hh<CR><LF>

 Field Number: 
  1) Heading Degrees, True
  2) T = True
  3) Heading Degrees, Magnetic
  4) M = Magnetic
  5) Checksum

 LCD - Loran-C Signal Data

        1    2   3   4   5   6   7   8   9   10  11  12  13  14
        |    |   |   |   |   |   |   |   |   |   |   |   |   |
 $--LCD,xxxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx*hh<CR><LF>

 Field Number: 
  1) GRI Microseconds/10
  2) Master Relative SNR
  3) Master Relative ECD
  4) Time Difference 1 Microseconds
  5) Time Difference 1 Signal Status
  6) Time Difference 2 Microseconds
  7) Time Difference 2 Signal Status
  8) Time Difference 3 Microseconds
  9) Time Difference 3 Signal Status
 10) Time Difference 4 Microseconds
 11) Time Difference 4 Signal Status
 12) Time Difference 5 Microseconds
 13) Time Difference 5 Signal Status
 14) Checksum

 MTW - Water Temperature

        1   2 3
        |   | | 
 $--MTW,x.x,C*hh<CR><LF>

 Field Number: 
  1) Degrees
  2) Unit of Measurement, Celcius
  3) Checksum

 MWV - Wind Speed and Angle

        1   2 3   4 5
        |   | |   | |
 $--MWV,x.x,a,x.x,a*hh<CR><LF>

 Field Number: 
  1) Wind Angle, 0 to 360 degrees
  2) Reference, R = Relative, T = True
  3) Wind Speed
  4) Wind Speed Units, K/M/N
  5) Status, A = Data Valid
  6) Checksum

 OLN - Omega Lane Numbers

        1          2          3          4
        |--------+ |--------+ |--------+ |
 $--OLN,aa,xxx,xxx,aa,xxx,xxx,aa,xxx,xxx*hh<CR><LF>

 Field Number: 
  1) Omega Pair 1
  2) Omega Pair 1
  3) Omega Pair 1
  4) Checksum

 OSD - Own Ship Data

        1   2 3   4 5   6 7   8   9 10
        |   | |   | |   | |   |   | |
 $--OSD,x.x,A,x.x,a,x.x,a,x.x,x.x,a*hh<CR><LF>

 Field Number: 
  1) Heading, degrees true
  2) Status, A = Data Valid
  3) Vessel Course, degrees True
  4) Course Reference
  5) Vessel Speed
  6) Speed Reference
  7) Vessel Set, degrees True
  8) Vessel drift (speed)
  9) Speed Units
 10) Checksum

 R00 - Waypoints in active route

        1                n
        |                | 
 $--R00,c---c,c---c,....*hh<CR><LF>

 Field Number: 
  1) waypoint ID
  ...
  n) checksum

 RMA - Recommended Minimum Navigation Information
                                                    12
        1 2       3 4        5 6   7   8   9   10  11|
        | |       | |        | |   |   |   |   |   | |
 $--RMA,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,x.x,x.x,a*hh<CR><LF>

 Field Number: 
  1) Blink Warning
  2) Latitude
  3) N or S
  4) Longitude
  5) E or W
  6) Time Difference A, uS
  7) Time Difference B, uS
  8) Speed Over Ground, Knots
  9) Track Made Good, degrees true
 10) Magnetic Variation, degrees
 11) E or W
 12) Checksum

 RMB - Recommended Minimum Navigation Information
                                                             14
        1 2   3 4    5    6       7 8        9 10  11  12  13|
        | |   | |    |    |       | |        | |   |   |   | |
 $--RMB,A,x.x,a,c--c,c--c,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,A*hh<CR><LF>

 Field Number: 
  1) Status, V = Navigation receiver warning
  2) Cross Track error - nautical miles
  3) Direction to Steer, Left or Right
  4) TO Waypoint ID
  5) FROM Waypoint ID
  6) Destination Waypoint Latitude
  7) N or S
  8) Destination Waypoint Longitude
  9) E or W
 10) Range to destination in nautical miles
 11) Bearing to destination in degrees True
 12) Destination closing velocity in knots
 13) Arrival Status, A = Arrival Circle Entered
 14) Checksum

 RMC - Recommended Minimum Navigation Information
                                                            12
        1         2 3       4 5        6 7   8   9    10  11|
        |         | |       | |        | |   |   |    |   | |
 $--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh<CR><LF>

 Field Number: 
  1) UTC Time
  2) Status, V = Navigation receiver warning
  3) Latitude
  4) N or S
  5) Longitude
  6) E or W
  7) Speed over ground, knots
  8) Track made good, degrees true
  9) Date, ddmmyy
 10) Magnetic Variation, degrees
 11) E or W
 12) Checksum

 ROT - Rate Of Turn

        1   2 3
        |   | |
 $--ROT,x.x,A*hh<CR><LF>

 Field Number: 
  1) Rate Of Turn, degrees per minute, "-" means bow turns to port
  2) Status, A means data is valid
  3) Checksum

 RPM - Revolutions

        1 2 3   4   5 6
        | | |   |   | |
 $--RPM,a,x,x.x,x.x,A*hh<CR><LF>

 Field Number: 
  1) Sourse, S = Shaft, E = Engine
  2) Engine or shaft number
  3) Speed, Revolutions per minute
  4) Propeller pitch, % of maximum, "-" means astern
  5) Status, A means data is valid
  6) Checksum

 RSA - Rudder Sensor Angle

        1   2 3   4 5
        |   | |   | |
 $--RSA,x.x,A,x.x,A*hh<CR><LF>

 Field Number: 
  1) Starboard (or single) rudder sensor, "-" means Turn To Port
  2) Status, A means data is valid
  3) Port rudder sensor
  4) Status, A means data is valid
  5) Checksum

 RSD - RADAR System Data
                                                        14
        1   2   3   4   5   6   7   8   9   10  11 12 13|
        |   |   |   |   |   |   |   |   |   |   |   | | |
 $--RSD,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,a,a*hh<CR><LF>

 Field Number: 
  9) Cursor Range From Own Ship
 10) Cursor Bearing Degrees Clockwise From Zero
 11) Range Scale
 12) Range Units
 14) Checksum

 RTE - Routes

        1   2   3 4	 5		       x    n
        |   |   | |    |           |    |
 $--RTE,x.x,x.x,a,c--c,c--c, ..... c--c*hh<CR><LF>

 Field Number: 
  1) Total number of messages being transmitted
  2) Message Number
  3) Message mode
     c = complete route, all waypoints
     w = working route, the waypoint you just left, the waypoint you're heading to then all the rest
  4) Waypoint ID
  x) More Waypoints
  n) Checksum

 SFI - Scanning Frequency Information

        1   2   3      4                     x
        |   |   |      |                     |
 $--SFI,x.x,x.x,xxxxxx,c .......... xxxxxx,c*hh<CR><LF>

 Field Number: 
  1) Total Number Of Messages
  2) Message Number
  3) Frequency 1
  4) Mode 1
  x) Checksum

 STN - Multiple Data ID

        1   2
        |   |
 $--STN,x.x,*hh<CR><LF>

 Field Number: 
  1) Talker ID Number
  2) Checksum

 TRF - TRANSIT Fix Data
                                                                    13
        1         2      3       4 5        6 7   8   9   10  11  12|
        |         |      |       | |        | |   |   |   |   |   | |
 $--TRF,hhmmss.ss,xxxxxx,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,x.x,xxx,A*hh<CR><LF>

 Field Number: 
  1) UTC Time
  2) Date, ddmmyy
  3) Latitude
  4) N or S
  5) Longitude
  6) E or W
  7) Elevation Angle
  8) Number of iterations
  9) Number of Doppler intervals
 10) Update distance, nautical miles
 11) Satellite ID
 12) Data Validity
 13) Checksum

 TTM - Tracked Target Message

                                         11     13
        1  2   3   4 5   6   7 8   9   10|    12| 14
        |  |   |   | |   |   | |   |   | |    | | |
 $--TTM,xx,x.x,x.x,a,x.x,x.x,a,x.x,x.x,a,c--c,a,a*hh<CR><LF>

 Field Number: 
  1) Target Number
  2) Target Distance
  3) Bearing from own ship
  4) Bearing Units
  5) Target speed
  6) Target Course
  7) Course Units
  8) Distance of closest-point-of-approach
  9) Time until closest-point-of-approach "-" means increasing
 10) "-" means increasing
 11) Target name
 12) Target Status
 13) Reference Target
 14) Checksum

 VBW - Dual Ground/Water Speed

        1   2   3 4   5   6 7
        |   |   | |   |   | |
 $--VBW,x.x,x.x,A,x.x,x.x,A*hh<CR><LF>

 Field Number: 
  1) Longitudinal water speed, "-" means astern
  2) Transverse water speed, "-" means port
  3) Status, A = Data Valid
  4) Longitudinal ground speed, "-" means astern
  5) Transverse ground speed, "-" means port
  6) Status, A = Data Valid
  7) Checksum

 VDR - Set and Drift

        1   2 3   4 5   6 7
        |   | |   | |   | |
 $--VDR,x.x,T,x.x,M,x.x,N*hh<CR><LF>

 Field Number: 
  1) Degress True
  2) T = True
  3) Degrees Magnetic
  4) M = Magnetic
  5) Knots (speed of current)
  6) N = Knots
  7) Checksum

 VHW - Water speed and heading

        1   2 3   4 5   6 7   8 9
        |   | |   | |   | |   | |
 $--VHW,x.x,T,x.x,M,x.x,N,x.x,K*hh<CR><LF>

 Field Number: 
  1) Degress True
  2) T = True
  3) Degrees Magnetic
  4) M = Magnetic
  5) Knots (speed of vessel relative to the water)
  6) N = Knots
  7) Kilometers (speed of vessel relative to the water)
  8) K = Kilometers
  9) Checksum

 VLW - Distance Traveled through Water

        1   2 3   4 5
        |   | |   | |
 $--VLW,x.x,N,x.x,N*hh<CR><LF>

 Field Number: 
  1) Total cumulative distance
  2) N = Nautical Miles
  3) Distance since Reset
  4) N = Nautical Miles
  5) Checksum

 VPW - Speed - Measured Parallel to Wind

        1   2 3   4 5
        |   | |   | |
 $--VPW,x.x,N,x.x,M*hh<CR><LF>

 Field Number: 
  1) Speed, "-" means downwind
  2) N = Knots
  3) Speed, "-" means downwind
  4) M = Meters per second
  5) Checksum

 VTG - Track made good and Ground speed

        1   2 3   4 5	 6 7   8 9
        |   | |   | |	 | |   | |
 $--VTG,x.x,T,x.x,M,x.x,N,x.x,K*hh<CR><LF>

 Field Number: 
  1) Track Degrees
  2) T = True
  3) Track Degrees
  4) M = Magnetic
  5) Speed Knots
  6) N = Knots
  7) Speed Kilometers Per Hour
  8) K = Kilometers Per Hour
  9) Checksum

 VWR - Relative Wind Speed and Angle

         1  2  3  4  5  6  7  8 9
         |  |  |  |  |  |  |  | |
 $--VWR,x.x,a,x.x,N,x.x,M,x.x,K*hh<CR><LF>

 Field Number: 
  1) Wind direction magnitude in degrees
  2) Wind direction Left/Right of bow
  3) Speed
  4) N = Knots
  5) Speed
  6) M = Meters Per Second
  7) Speed
  8) K = Kilometers Per Hour
  9) Checksum

 WCV - Waypoint Closure Velocity

        1   2 3    4
        |   | |    |
 $--WCV,x.x,N,c--c*hh<CR><LF>

 Field Number: 
  1) Velocity
  2) N = knots
  3) Waypoint ID
  4) Checksum

 WNC - Distance - Waypoint to Waypoint

        1   2 3   4 5    6    7
        |   | |   | |    |    |
 $--WNC,x.x,N,x.x,K,c--c,c--c*hh<CR><LF>

 Field Number: 
  1) Distance, Nautical Miles
  2) N = Nautical Miles
  3) Distance, Kilometers
  4) K = Kilometers
  5) TO Waypoint
  6) FROM Waypoint
  7) Checksum

 WPL - Waypoint Location

	1       2 3        4 5    6
        |       | |        | |    |
 $--WPL,llll.ll,a,yyyyy.yy,a,c--c*hh<CR><LF>

 Field Number: 
  1) Latitude
  2) N or S (North or South)
  3) Longitude
  4) E or W (East or West)
  5) Waypoint name
  6) Checksum     

 XDR - Cross Track Error - Dead Reckoning

        1 2   3 4			    n
        | |   | |            |
 $--XDR,a,x.x,a,c--c, ..... *hh<CR><LF>

 Field Number: 
  1) Transducer Type
  2) Measurement Data
  3) Units of measurement
  4) Name of transducer
  x) More of the same
  n) Checksum

 XTE - Cross-Track Error, Measured

        1 2 3   4 5  6
        | | |   | |  |
 $--XTE,A,A,x.x,a,N,*hh<CR><LF>

 Field Number: 
  1) Status
     V = LORAN-C Blink or SNR warning
     V = general warning flag or other navigation systems when a reliable
         fix is not available
  2) Status
     V = Loran-C Cycle Lock warning flag
     A = OK or not used
  3) Cross Track Error Magnitude
  4) Direction to steer, L or R
  5) Cross Track Units, N = Nautical Miles
  6) Checksum

 XTR - Cross Track Error - Dead Reckoning

        1   2 3 4
        |   | | |
 $--XTR,x.x,a,N*hh<CR><LF>

 Field Number: 
  1) Magnitude of cross track error
  2) Direction to steer, L or R
  3) Units, N = Nautical Miles
  4) Checksum

 ZDA - Time & Date
 UTC, day, month, year and local time zone

	1         2  3  4    5  6  7
        |         |  |  |    |  |  |
 $--ZDA,hhmmss.ss,xx,xx,xxxx,xx,xx*hh<CR><LF>

 Field Number: 
  1) Local zone minutes description, same sign as local hours
  2) Local zone description, 00 to +- 13 hours
  3) Year
  4) Month, 01 to 12
  5) Day, 01 to 31
  6) Universal Time Coordinated (UTC)
  7) Checksum

 ZFO - UTC & Time from origin Waypoint

        1         2         3    4
        |         |         |    |
 $--ZFO,hhmmss.ss,hhmmss.ss,c--c*hh<CR><LF>

 Field Number: 
  1) Universal Time Coordinated (UTC)
  2) Elapsed Time
  3) Origin Waypoint ID
  4) Checksum

 ZTG - UTC & Time to Destination Waypoint

        1         2         3    4
        |         |         |    |
 $--ZTG,hhmmss.ss,hhmmss.ss,c--c*hh<CR><LF>

 Field Number: 
  1) Universal Time Coordinated (UTC)
  2) Time Remaining
  3) Destination Waypoint ID
  4) Checksum

****************************************************************

New found in web: (data fields unknown)

DSC - Digital Selective Calling Information
DSE - Extended DSC
DSI - DSC Transponder Initiate
DSR - DSC Transponder Response
DTM - Datum Reference
GBS - GPS Satellite Fault Detection
GRS - GPS Range Residuals
GST - GPS Pseudorange Noise Statistics
MSK - MSK Receiver Interface 
MSS - MSK Receiver Signal Status 
MWD - Wind Direction & Speed
TLL - Target Latitude and Longitude
WDC - Distance to Waypoint - Great Circle
WDR - Distance to Waypoint - Rhumb Line
ZDL - Time and Distance to Variable Point