Restructured to allow sentences to be loaded from files

nmea.js

@@ -0,0 +1,99 @@
+module.exports = function() {
+  function toSentence(parts) {
+    var base = parts.join(',');
+    return base + computeChecksum(base);
+  }
+  var m_hex = [
+    '0',
+    '1',
+    '2',
+    '3',
+    '4',
+    '5',
+    '6',
+    '7',
+    '8',
+    '9',
+    'A',
+    'B',
+    'C',
+    'D',
+    'E',
+    'F'
+  ];
+
+  function computeChecksum(sentence) {
+    var c1;
+    var i;
+
+    // skip the $
+    i = 1;
+
+    // init to first character    var count;
+
+    c1 = sentence.charCodeAt(i);
+
+    // process rest of characters, zero delimited
+    for (i = 2; i < sentence.length; ++i) {
+      c1 = c1 ^ sentence.charCodeAt(i);
+    }
+
+    return '*' + toHexString(c1);
+  };
+
+  function toHexString(v) {
+    var lsn;
+    var msn;
+
+    msn = (v >> 4) & 0x0f;
+    lsn = (v >> 0) & 0x0f;
+    return m_hex[msn] + m_hex[lsn];
+  };
+
+  function radsToDeg(radians) {
+    return radians * 180 / Math.PI
+  }
+
+  function msToKnots(v) { 
+    return v*3600/1852.0; 
+  }
+
+  function msToKM(v) { 
+    return v*3600.0/1000.0; 
+  }
+
+  function mToNm(v) {
+    return v*0.000539957;
+  }
+
+
+  function padd(n, p, c)
+  {
+    var pad_char = typeof c !== 'undefined' ? c : '0';
+    var pad = new Array(1 + p).join(pad_char);
+    return (pad + n).slice(-pad.length);
+  }
+
+  function toNmeaDegrees(val)
+  {
+    val = Math.abs(val)
+    var minutes = Math.floor(val)
+    var minutes_decimal = val % 1
+    minutes_decimal *= 60.0;
+    return padd(minutes.toFixed(0),2) + padd(minutes_decimal.toFixed(4), 7)
+  }
+
+  function fixAngle(d) {
+    if ( d > Math.PI ) d = d - Math.PI;
+    if ( d < -Math.PI) d = d + Math.PI;
+    return d;
+  }
+  return {
+    toSentence: toSentence,
+    radsToDeg: radsToDeg,
+    msToKnots: msToKnots,
+    msToKM: msToKM,
+    toNmeaDegrees: toNmeaDegrees,
+    fixAngle: fixAngle    
+  };
+}();

sentences/APB.js

@@ -0,0 +1,62 @@
+    /*
+      ------------------------------------------------------------------------------
+      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
+
+      Example: $GPAPB,A,A,0.10,R,N,V,V,011,M,DEST,011,M,011,M*82
+    */
+// to verify
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "APB - Autopilot info",
+      keys: [
+        'navigation.courseGreatCircle.crossTrackError', 'navigation.courseGreatCircle.bearingTrackTrue', 'navigation.courseGreatCircle.nextPoint'
+      ],
+      f: function(xte, originToDest, nextPoint) {
+        return nmea.toSentence([
+          '$SKAPB', 'A', 'A', Math.abs(xte), xte > 0
+            ? 'L'
+            : 'R',
+          'M',
+          'V',
+          'V',
+          nmea.radsToDeg(originToDest).toFixed(0),
+          'T',
+          '00',
+          nmea.radsToDeg(nextPoint.bearingTrue).toFixed(0),
+          'T',
+          nmea.radsToDeg(nextPoint.bearingMagnetic).toFixed(0),
+          'M'
+        ]);
+      }
+    };
+}

sentences/DBK.js

@@ -0,0 +1,23 @@
+// NMEA0183 Encoder DBK   $IIDBK,102.9,f,31.38,M,17.2,F*39
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "DBK - Depth Below Keel",
+      keys: [
+        'environment.depth.belowKeel'
+      ],
+      f: function mwv(depth) {
+        var feet = depth * 3.28084
+        var fathoms = depth * 0.546807
+        return nmea.toSentence([
+          '$IIDBK',
+          feet.toFixed(1),
+          'f',
+          depth.toFixed(2),
+          'M',
+          fathoms.toFixed(1),
+          'F'
+        ]);
+      }
+    };
+}

sentences/DBS.js

@@ -0,0 +1,23 @@
+// to verify
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "DBS - Depth Below Surface",
+      keys: [
+        'environment.depth.belowSurface'
+      ],
+      f: function mwv(depth) {
+        var feet = depth * 3.28084
+        var fathoms = depth * 0.546807
+        return nmea.toSentence([
+          '$IIDBS',
+          feet.toFixed(1),
+          'f',
+          depth.toFixed(2),
+          'M',
+          fathoms.toFixed(1),
+          'F'
+        ]);
+      }
+    };
+}

sentences/DBT.js

@@ -0,0 +1,23 @@
+// NMEA0183 Encoder DBT   $IIDBT,103.0,f,31.38,M,17.2,F*2E
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "DBT - Depth Below Transducer",
+      keys: [
+        'environment.depth.belowTransducer'
+      ],
+      f: function mwv(depth) {
+        var feet = depth * 3.28084
+        var fathoms = depth * 0.546807
+        return nmea.toSentence([
+          '$IIDBT',
+          feet.toFixed(1),
+          'f',
+          depth.toFixed(2),
+          'M',
+          fathoms.toFixed(1),
+          'F'
+        ]);
+      }
+    };
+};

sentences/DPT.js

@@ -0,0 +1,28 @@
+
+ /**
+Depth:
+$IIDPT,x.x,x.x,,*hh
+ I I_Sensor offset, >0 = surface transducer distance, >0 = keel transducer distance.
+ I_Bottom transducer distance
+
+
+
+ */
+// NMEA0183 Encoder DPT   $IIDPT,69.21,-0.001*60
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "DPT - Depth",
+      keys: [
+        'environment.depth.belowTransducer', 'environment.depth.transducerToKeel'
+      ],
+      f: function dpt(belowTransducer, transducerToKeel) {
+        return nmea.toSentence([
+          '$IIDPT',
+          belowTransducer.toFixed(2),
+          transducerToKeel.toFixed(3)
+        ]);
+      }
+    };
+}
+

sentences/GLL.js

@@ -0,0 +1,37 @@
+
+
+
+ /*
+Geographical position, latitude and longitude:
+$IIGLL,IIII.II,a,yyyyy.yy,a,hhmmss.ss,A,A*hh
+ I I I I I I_Statut, A= valid data, V= non valid data
+ I I I I I_UTC time
+ I I I___ I_Longitude, E/W
+ I__I_Latidude, N/S 
+*/
+// NMEA0183 Encoder GLL   $IIGLL,5943.4970,N,2444.1983,E,200001.020,A*16
+
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "GLL - Geographical position, latitude and longitude",
+      keys: [
+        'navigation.datetime', 'navigation.position'
+      ],
+      f: function gll(datetime8601, position) {
+        var datetime = new Date(datetime8601);
+        var hours = ('00' + datetime.getHours()).slice(-2);
+        var minutes = ('00' + datetime.getMinutes()).slice(-2);
+        var seconds = ('00' + datetime.getSeconds()).slice(-2);
+        return nmea.toSentence([
+          '$IIGLL',
+          nmea.toNmeaDegrees(position.latitude),
+          position.latitude < 0 ? 'S' : 'N',
+          nmea.toNmeaDegrees(position.longitude),
+          position.longitude < 0 ? 'W' : 'E',
+          hours + minutes + seconds + '.020',
+          'A'
+        ]);
+      }
+    };
+}

sentences/HDG.js

@@ -0,0 +1,29 @@
+
+
+
+/*
+Heading magnetic:
+$IIHDG,x.x,,,,*hh
+ I_Heading magnetic
+ */
+// NMEA0183 Encoder HDG   $IIHDG,206.71,,,,*7B
+
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "HDG - Heading magnetic:.",
+      keys: [
+        'navigation.headingMagnetic'
+      ],
+      f: function hdg(headingMagnetic) {
+        return nmea.toSentence([
+          '$IIHDG',
+          nmea.radsToDeg(headingMagnetic).toFixed(2),
+          '',
+          '',
+          '',
+          ''
+        ]);
+      }
+  };
+}

sentences/HDM.js

@@ -0,0 +1,18 @@
+// NMEA0183 Encoder HDM   $IIHDM,206.7,M*21  
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "HDM - Heading Magnetic",
+      keys: [
+        'navigation.headingMagnetic'
+      ],
+      f: function mwv(heading) {
+        return nmea.toSentence([
+          '$IIHDM',
+          nmea.radsToDeg(heading).toFixed(1),
+          'M'
+        ]);
+      }
+  };
+}
+

sentences/HDMC.js

@@ -0,0 +1,18 @@
+// NMEA0183 Encoder HDMC   $IIHDM,212.2,M*21
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "HDM - Heading Magnetic, calculated from True",
+      keys: [
+        'navigation.headingTrue', 'navigation.magneticVariation'
+      ],
+      f: function mwv(headingTrue, magneticVariation) {
+        var heading = headingTrue + magneticVariation;
+        return nmea.toSentence([
+          '$IIHDM',
+          nmea.radsToDeg(heading).toFixed(1),
+          'M'
+        ]);
+      }
+  };
+}

sentences/HDT.js

@@ -0,0 +1,20 @@
+
+//NMEA0183 Encoder HDT   $IIHDT,200.1,T*21
+const nmea = require('../nmea.js');
+module.exports = function(app) {
+  return {
+      title: "HDT - Heading True",
+      keys: [
+        'navigation.headingTrue'
+      ],
+      f: function mwv(heading) {
+        return nmea.toSentence([
+          '$IIHDT',
+          nmea.radsToDeg(heading).toFixed(1),
+          'T'
+        ]);
+      }
+  };
+}
+
+