####################### # RBR Duet TP ####################### timestamp-iso1806, uptime-msec, temperature-degC, pressure-dbar Where: timestamp-iso1806 : date and time in ISO1806 format (yyyy/mm/ddThh:mm:ss.sssZ) uptime-msec : elapsed time since last start or sample rate change (milliseconds) temperature-degC : temperature (degrees C) pressure-dbar : pressure (decibar) ####################### # Honeywell HMR3300 Heading ####################### timestamp-iso1806, HX-heading-deg, HY-pitch-deg, HZ-roll-deg Where: timestamp-iso1806 : date and time in ISO1806 format (yyyy/mm/ddThh:mm:ss.sssZ) HX-heading-deg : heading degrees (range 0:360) HY-pitch-deg : pitch degrees (range -60:+60) HZ-roll-deg : roll degrees (range -60:+60) ####################### # Annotation ####################### timestamp-iso1806, message-txt Where: timestamp-iso1806 : date and time in ISO1806 format (yyyy/mm/ddThh:mm:ss.sssZ) message-txt : annotation string A new record is written each time a newline is sent from the annotation terminal session. ####################### # PLC ####################### timestamp-iso1806, event-text Where: timestamp-iso1806 : date and time in ISO1806 format (yyyy/mm/ddThh:mm:ss.sssZ) event-txt : text message describing PLC events, e.g. button presses. PLC events include : REC_START, REC_STOP : start/stop recording COMMS_ERR : communications error ####################### # Garmin 19xHVS GPS ####################### timestamp-iso1806, message-GPGGA timestamp-iso1806, message-GPRMC timestamp-iso1806, message-GPGSV Where: timestamp-iso1806 : date and time in ISO1806 format (yyyy/mm/ddThh:mm:ss.sssZ) message-GPxxx are NMEA0183 sentences, described below GGA - essential fix data which provide 3D location and accuracy data. $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47 Where: GGA Global Positioning System Fix Data 123519 Fix taken at 12:35:19 UTC 4807.038,N Latitude 48 deg 07.038' N 01131.000,E Longitude 11 deg 31.000' E 1 Fix quality: 0 = invalid 1 = GPS fix (SPS) 2 = DGPS fix 3 = PPS fix 4 = Real Time Kinematic 5 = Float RTK 6 = estimated (dead reckoning) (2.3 feature) 7 = Manual input mode 8 = Simulation mode 08 Number of satellites being tracked 0.9 Horizontal dilution of position 545.4,M Altitude, Meters, above mean sea level 46.9,M Height of geoid (mean sea level) above WGS84 ellipsoid (empty field) time in seconds since last DGPS update (empty field) DGPS station ID number *47 the checksum data, always begins with * If the height of geoid is missing then the altitude should be suspect. Some non-standard implementations report altitude with respect to the ellipsoid rather than geoid altitude. Some units do not report negative altitudes at all. This is the only sentence that reports altitude. RMC - NMEA has its own version of essential gps pvt (position, velocity, time) data. It is called RMC, The Recommended Minimum, which will look similar to: $GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A Where: RMC Recommended Minimum sentence C 123519 Fix taken at 12:35:19 UTC A Status A=active or V=Void. 4807.038,N Latitude 48 deg 07.038' N 01131.000,E Longitude 11 deg 31.000' E 022.4 Speed over the ground in knots 084.4 Track angle in degrees True 230394 Date - 23rd of March 1994 003.1,W Magnetic Variation *6A The checksum data, always begins with * Note that, as of the 2.3 release of NMEA, there is a new field in the RMC sentence at the end just prior to the checksum. For more information on this field see here. GSV - Satellites in View shows data about the satellites that the unit might be able to find based on its viewing mask and almanac data. It also shows current ability to track this data. Note that one GSV sentence only can provide data for up to 4 satellites and thus there may need to be 3 sentences for the full information. It is reasonable for the GSV sentence to contain more satellites than GGA might indicate since GSV may include satellites that are not used as part of the solution. It is not a requirment that the GSV sentences all appear in sequence. To avoid overloading the data bandwidth some receivers may place the various sentences in totally different samples since each sentence identifies which one it is. The field called SNR (Signal to Noise Ratio) in the NMEA standard is often referred to as signal strength. SNR is an indirect but more useful value that raw signal strength. It can range from 0 to 99 and has units of dB according to the NMEA standard, but the various manufacturers send different ranges of numbers with different starting numbers so the values themselves cannot necessarily be used to evaluate different units. The range of working values in a given gps will usually show a difference of about 25 to 35 between the lowest and highest values, however 0 is a special case and may be shown on satellites that are in view but not being tracked. $GPGSV,2,1,08,01,40,083,46,02,17,308,41,12,07,344,39,14,22,228,45*75 Where: GSV Satellites in view 2 Number of sentences for full data 1 sentence 1 of 2 08 Number of satellites in view 01 Satellite PRN number 40 Elevation, degrees 083 Azimuth, degrees 46 SNR - higher is better for up to 4 satellites per sentence *75 the checksum data, always begins with *