feat: 导入 NMEA-0183 GPS 协议解析库（node-nmea）

NMEA-0183 语句解析器，含 21 个语句类型 codec 与配套单元测试。

- codecs/：APB/BWC/DBT/GGA/GLL/GRMT/GSA/GSV/HDG/HDM/HDT/MWV/RDID/
  RMB/RMC/ROT/RSA/TXT/VTG/VWR/ZDA
- test/：各 codec 对应的 mocha 用例
- .github/workflows/：node与 npm-publish 流水线

许可证：MIT（原作者 James Penn）

codecs/GGA.js

@@ -0,0 +1,72 @@
+var helpers = require("../helpers.js")
+
+exports.TYPE = 'fix';
+exports.ID = 'GGA';
+
+/*
+                                                     11
+       1         2       3 4        5 6 7  8   9  10 |  12 13  14  15
+       |         |       | |        | | |  |   |   | |   | |   |   |
+$--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh
+ 1) Time (UTC)
+ 2) Latitude
+ 3) N or S (North or South)
+ 4) Longitude
+ 5) E or W (East or West)
+ 6) GPS Quality Indicator,
+ 0 - fix not available,
+ 1 - GPS fix,
+ 2 - Differential GPS fix
+ 7) Number of satellites in view, 00 - 12
+ 8) Horizontal Dilution of precision
+ 9) Antenna Altitude above/below mean-sea-level (geoid)
+10) Units of antenna altitude, meters
+11) Geoidal separation, the difference between the WGS-84 earth
+ ellipsoid and mean-sea-level (geoid), "-" means mean-sea-level below ellipsoid
+12) Units of geoidal separation, meters
+13) Age of differential GPS data, time in seconds since last SC104
+ type 1 or 9 update, null field when DGPS is not used
+14) Differential reference station ID, 0000-1023
+15) Checksum
+*/
+var FIX_TYPE = ['none', 'fix', 'delta','pps','rtk','frtk','estimated','manual','simulation'];
+
+exports.decode = function(fields) {
+  return {
+    sentence: exports.ID,
+    type: exports.TYPE,
+    timestamp: fields[1],
+    lat: fields[2],
+    latPole: fields[3],
+    lon: fields[4],
+    lonPole: fields[5],
+    fixType: FIX_TYPE[+fields[6]],
+    numSat: +fields[7],
+    horDilution: +fields[8],
+    alt: +fields[9],
+    altUnit: fields[10],
+    geoidalSep: +fields[11],
+    geoidalSepUnit: fields[12],
+    differentialAge: +fields[13],
+    differentialRefStn: fields[14]
+  };
+}
+
+exports.encode = function (talker, msg) {
+  var result = ['$' + talker + exports.ID];
+  result.push(helpers.encodeTime(msg.timestamp));
+  result.push(helpers.encodeDegrees(msg.lat));
+  result.push(msg.latPole);
+  result.push(helpers.encodeDegrees(msg.lon));
+  result.push(msg.lonPole);
+  result.push(FIX_TYPE.indexOf(msg.fixType));
+  result.push(helpers.encodeValue(msg.numSat));
+  result.push(helpers.encodeFixed(msg.horDilution, 1));
+  result.push(helpers.encodeAltitude(msg.alt));
+  result.push(helpers.encodeGeoidalSeperation(msg.geoidalSep));
+  result.push(helpers.encodeFixed(msg.differentialAge, 2));
+  result.push(msg.differentialRefStn);
+
+  var resultMsg = result.join(',');
+  return resultMsg + helpers.computeChecksum(resultMsg);
+}