diff --git a/README.md b/README.md
index 8b6be097..1ef6960e 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,9 @@
 - [HSC - Heading Steering Command](https://www.tronico.fi/OH6NT/docs/NMEA0183.pdf)
 - KEP - NKE Performance data
 - [MDA - Meteorological Composite](https://gpsd.gitlab.io/gpsd/NMEA.html#_mda_meteorilogical_composite)
+- [MTA - Mean Temperature of Air](https://www.nmea.org/Assets/100108_nmea_0183_sentences_not_recommended_for_new_designs.pdf)
 - [MTW - Mean Temperature of Water](https://gpsd.gitlab.io/gpsd/NMEA.html#_mtw_mean_temperature_of_water)
+- [MWD - Wind Speed and Direction](https://lists.nongnu.org/archive/html/gpsd-dev/2012-04/msg00048.html)
 - [MWV - Wind Speed and Angle](https://gpsd.gitlab.io/gpsd/NMEA.html#_mwv_wind_speed_and_angle)
 - [RMB - Recommended Minimum Navigation Information](https://gpsd.gitlab.io/gpsd/NMEA.html#_rmb_recommended_minimum_navigation_information)
 - [RMC - Recommended Minimum Navigation Information](https://gpsd.gitlab.io/gpsd/NMEA.html#_rmc_recommended_minimum_navigation_information)
@@ -38,6 +40,7 @@
 - [VPW - Speed - Measured Parallel to Wind](https://gpsd.gitlab.io/gpsd/NMEA.html#_vpw_speed_measured_parallel_to_wind)
 - [VTG - Track Made Good and Ground Speed](https://gpsd.gitlab.io/gpsd/NMEA.html#_vtg_track_made_good_and_ground_speed)
 - [VWR - Relative Wind Speed and Angle](https://gpsd.gitlab.io/gpsd/NMEA.html#_vwr_relative_wind_speed_and_angle)
+- [VWT - True Wind Angle and Speed](https://lists.nongnu.org/archive/html/gpsd-dev/2012-04/msg00048.html)
 - [ZDA - UTC day, month, and year, and local time zone offset](https://gpsd.gitlab.io/gpsd/NMEA.html#_zda_time_amp_date_utc_day_month_year_and_local_time_zone)
 - [XTE - Cross-track Error](https://www.tronico.fi/OH6NT/docs/NMEA0183.pdf)
 - [ZDA - UTC day, month, and year, and local time zone offset](http://www.trimble.com/oem_receiverhelp/v4.44/en/NMEA-0183messages_ZDA.html)
diff --git a/hooks/MTA.js b/hooks/MTA.js
new file mode 100644
index 00000000..b898efd6
--- /dev/null
+++ b/hooks/MTA.js
@@ -0,0 +1,57 @@
+/**
+ * Copyright 2016 Signal K <info@signalk.org> and contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict'
+
+ const utils = require('@signalk/nmea0183-utilities')
+
+ /*
+  * MTA - Mean Temperature of Air
+  *
+  *        0   1 2
+  *        |   | |
+  * $--MTA,x.x,C*hh<CR><LF>
+  *
+  * Field Number:
+  *   0.    Degrees
+  *   1.    Unit of Measurement, Celcius
+  *   2.    Checksum
+  *
+  */
+
+module.exports = function (input) {
+  const { id, sentence, parts, tags } = input;
+
+  if(parts[1] != 'C') {
+      return null;
+  }
+  const delta = {
+    updates: [
+      {
+        source: tags.source,
+        timestamp: tags.timestamp,
+        values: [
+          {
+            path: 'environment.outside.temperature',
+            value: utils.transform(utils.float(parts[0]), 'c', 'k')
+          }
+        ]
+      }
+    ],
+  }
+
+  return delta
+}
diff --git a/hooks/MWD.js b/hooks/MWD.js
new file mode 100644
index 00000000..7538b9be
--- /dev/null
+++ b/hooks/MWD.js
@@ -0,0 +1,93 @@
+'use strict'
+
+/**
+ * Copyright 2016 Signal K and Fabian Tollenaar <fabian@signalk.org>.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const debug = require('debug')('signalk-parser-nmea0183/MWD')
+const utils = require('@signalk/nmea0183-utilities')
+
+/*
+ * $WIMWD,<0>,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh
+ *
+ * NMEA 0183 standard Wind Direction and Speed, with respect to north.
+ *
+ * <0> Wind direction, 0.0 to 359.9 degrees True, to the nearest 0.1 degree
+ * <1> T = True
+ * <2> Wind direction, 0.0 to 359.9 degrees Magnetic, to the nearest 0.1 degree
+ * <3> M = Magnetic
+ * <4> Wind speed, knots, to the nearest 0.1 knot.
+ * <5> N = Knots
+ * <6> Wind speed, meters/second, to the nearest 0.1 m/s.
+ * <7> M = Meters/second
+ */
+
+module.exports = function(input) {
+    const { id, sentence, parts, tags } = input;
+    var pathValues = [];
+
+    // get direction data:
+    // return both, true and magnetic direction, if present in the NMEA sentence
+    var haveDirection = false;
+    if(parts[0] != '' && parts[1] == 'T') {
+	haveDirection = true;
+	pathValues.push({
+	    'path': 'environment.wind.directionTrue',
+	    'value': utils.transform(utils.float(parts[0]), 'deg', 'rad')
+	})
+    }
+    if(parts[2] != '' && parts[3] == 'M') {
+	haveDirection = true;
+	pathValues.push({
+	    'path': 'environment.wind.directionMagnetic',
+	    'value': utils.transform(utils.float(parts[2]), 'deg', 'rad')
+	})
+    }
+    if( !haveDirection ) {
+	return null;
+    }
+    
+    // get speed data:
+    // speed given in kn is used in case no speed in m/s is present in the NMEA sentence
+    var haveSpeed = false;
+    var speed;
+    if(parts[4] != '' && parts[5] == 'N') {
+	haveSpeed = true;
+	speed = utils.transform(utils.float(parts[4]), 'knots', 'ms');
+    }
+    if(parts[6] != '' && parts[7] == 'M') {  
+	haveSpeed = true;
+	speed = utils.float(parts[6]);
+    }
+    if( !haveSpeed ) {
+	return null;
+    }
+    pathValues.push({
+	'path': 'environment.wind.speedTrue',
+	'value': speed
+    })
+
+    const delta = {
+	updates: [
+	    {
+		source: tags.source,
+		timestamp: tags.timestamp,
+		values: pathValues
+	    }
+	],
+    }
+
+    return delta
+}
diff --git a/hooks/VWT.js b/hooks/VWT.js
new file mode 100644
index 00000000..424f46a4
--- /dev/null
+++ b/hooks/VWT.js
@@ -0,0 +1,116 @@
+'use strict'
+
+/**
+ * Copyright 2016 Signal K and Fabian Tollenaar <fabian@signalk.org>.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const debug = require('debug')('signalk-parser-nmea0183/VWT')
+const utils = require('@signalk/nmea0183-utilities')
+
+/*
+ * $WIVWT,<0>,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh
+ *
+ * NMEA 0183 True wind angle in relation to the vessel's heading, and true wind
+ * speed referenced to the water. True wind is the vector sum of the Relative
+ * (apparent) wind vector and the vessel's velocity vector relative to the water along
+ * the heading line of the vessel. It represents the wind at the vessel if it were
+ * stationary relative to the water and heading in the same direction.
+ *
+ * <0> Calculated wind angle relative to the vessel, 0 to 180°, left/right of
+ *     vessel heading, to the nearest 0.1 degree
+ * <1> L = left, or R = right
+ * <2> Calculated wind speed, knots, to the nearest 0.1 knot
+ * <3> N = knots
+ * <4> Wind speed, meters per second, to the nearest 0.1 m/s
+ * <5> M = meters per second
+ * <6> Wind speed, km/h, to the nearest km/h
+ * <7> K = km/h
+ */
+
+// $IIVWT,030.,R,10.1,N,05.2,M,018.7,K*75
+
+
+function convertToWindAngle(angle) {
+  const numAngle = utils.float(angle) % 360
+  if (numAngle > 180 && numAngle <= 360) {
+    return numAngle - 360
+  }
+  return numAngle
+}
+
+module.exports = function(input) {
+    const { id, sentence, parts, tags } = input;
+
+    // get direction
+    if(!parts[0]) {
+	return null;
+    }
+    var angle = convertToWindAngle(parts[0]);
+
+    if(!parts[1]) {
+	return null;
+    }
+    switch( parts[1] ) {
+    case 'L':
+	angle = -1 * utils.transform( angle, 'deg', 'rad');
+	break;
+    case 'R':
+	angle = utils.transform( angle, 'deg', 'rad');
+	break;
+    default:
+	return null;
+    }
+
+    // get speed data:
+    // speed value given in m/s is given precedence if present in the NMEA sentence
+    var haveSpeed = false;
+    var speed;
+    if(parts[2] != '' && parts[3] == 'N') {
+	haveSpeed = true;
+	speed = utils.transform(utils.float(parts[2]), 'knots', 'ms');
+    }
+    if(parts[6] != '' && parts[7] == 'K') {
+	haveSpeed = true;
+	speed = utils.transform(utils.float(parts[6]), 'kph', 'ms');
+    }
+    if(parts[4] != '' && parts[5] == 'M') { // overwrite speed from knots or km/h if present
+	haveSpeed = true;
+	speed = utils.float(parts[4]);
+    }
+    if( !haveSpeed ) {
+	return null;
+    }
+		
+    const delta = {
+	updates: [
+	    {
+		source: tags.source,
+		timestamp: tags.timestamp,
+		values: [
+		    {
+			path: 'environment.wind.speedTrue',
+			value: speed
+		    },
+		    {
+			path: 'environment.wind.angleTrueWater',
+			value: angle
+		    }
+		]
+	    }
+	],
+    }
+
+    return delta
+}
diff --git a/hooks/index.js b/hooks/index.js
index d0c68f21..5083c5cb 100644
--- a/hooks/index.js
+++ b/hooks/index.js
@@ -14,7 +14,9 @@ module.exports = {
   'PBVE': require('./proprietary/PBVE.js'),
   'PNKEP': require('./proprietary/PNKEP.js'),
   'MDA': require('./MDA.js'),
+  'MTA': require('./MTA.js'),
   'MTW': require('./MTW.js'),
+  'MWD': require('./MWD.js'),
   'MWV': require('./MWV.js'),
   'RMB': require('./RMB.js'),
   'RMC': require('./RMC.js'),
@@ -29,6 +31,7 @@ module.exports = {
   'VPW': require('./VPW.js'),
   'VTG': require('./VTG.js'),
   'VWR': require('./VWR.js'),
+  'VWT': require('./VWT.js'),
   'ZDA': require('./ZDA.js'),
   'XTE': require('./XTE.js'),
   'BOD': require('./BOD.js'),
diff --git a/test/MTA.js b/test/MTA.js
new file mode 100644
index 00000000..5902909b
--- /dev/null
+++ b/test/MTA.js
@@ -0,0 +1,38 @@
+/**
+ * Copyright 2016 Signal K and contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict'
+
+const Parser = require('../lib')
+const chai = require('chai')
+const should = chai.Should()
+
+chai.use(require('chai-things'))
+
+describe('MTA', () => {
+    it('Converts OK using individual parser', () => {
+	const delta = new Parser().parse('$IIMTA,26.,C*31')
+
+	delta.updates[0].values[0].path.should.equal('environment.outside.temperature')
+	delta.updates[0].values[0].value.should.be.closeTo(299.15, 0.005)
+    })
+    it('Does not accept units other than Celsius', () => {
+	var should = chai.should();
+	const delta = new Parser().parse('$IIMTA,26.,F*34')
+
+	should.equal(delta,null);
+    })
+})
diff --git a/test/MWD.js b/test/MWD.js
new file mode 100644
index 00000000..d180326b
--- /dev/null
+++ b/test/MWD.js
@@ -0,0 +1,109 @@
+/**
+ * Copyright 2016 Signal K and contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict'
+
+const Parser = require('../lib')
+const chai = require('chai')
+const should = chai.Should()
+
+chai.use(require('chai-things'))
+
+describe('MWD', () => {
+
+    it('speed & direction data (#1)', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,M,10.1,N,05.2,M*0B')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.directionMagnetic')
+	delta.updates[0].values[0].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[1].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[1].value.should.equal(5.2)
+    })
+
+    it('speed & direction data (#2)', () => {
+	const delta = new Parser().parse('$IIMWD,046.,T,046.,M,10.1,N,,*17')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.directionTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[1].path.should.equal('environment.wind.directionMagnetic')
+	delta.updates[0].values[1].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[2].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[2].value.should.be.closeTo(5.2, 0.005)
+    })
+
+    it('speed & direction data (#3)', () => {
+	const delta = new Parser().parse('$IIMWD,046.,T,,,,,5.2,M*72')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.directionTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[1].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[1].value.should.be.equal(5.2)
+    })
+
+    it('missing direction data', () => {
+	const delta = new Parser().parse('$IIMWD,,,,,,,5.2,M*3A')
+
+	should.equal(delta,null);
+    })
+
+    it('missing speed data', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,M,,,,*0F')
+
+	should.equal(delta,null);
+    })
+
+    it('improper direction designator (#1)', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,T,,,,*16')
+
+	should.equal(delta,null);
+    })
+
+    it('improper direction designator (#2)', () => {
+	const delta = new Parser().parse('$IIMWD,046.,M,,,,,,*0F')
+
+	should.equal(delta,null);
+    })
+
+    it('improper speed designator (#1)', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,M,10.1,n,,*7F')
+
+	should.equal(delta,null);
+    })
+
+    it('improper speed designator (#2)', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,M,,,0.0,m*4C')
+
+	should.equal(delta,null);
+    })
+
+    it('improper direction designator for degrees magnetic, using degrees true', () => {
+	const delta = new Parser().parse('$IIMWD,046.,T,0.,m,10.1,N,5.2,M*51')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.directionTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[1].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[1].value.should.equal(5.2)
+    })
+
+    it('improper speed designator for m/s, using speed in kn', () => {
+	const delta = new Parser().parse('$IIMWD,,,046.,M,10.1,N,0.0,m*1C')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.directionMagnetic')
+	delta.updates[0].values[0].value.should.be.closeTo(0.802851, 0.00005)
+	delta.updates[0].values[1].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[1].value.should.be.closeTo(5.2, 0.005)
+    })
+})
diff --git a/test/VWT.js b/test/VWT.js
new file mode 100644
index 00000000..d1779170
--- /dev/null
+++ b/test/VWT.js
@@ -0,0 +1,129 @@
+'use strict'
+
+const Parser = require('../lib')
+const chai = require('chai')
+const should = chai.Should()
+
+chai.use(require('chai-things'))
+
+describe('VWT', () => {
+    it('speed & direction data (#1)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,N,05.2,M,018.7,K*75')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('speed & direction data (#2)', () => {
+	const delta = new Parser().parse('$IIVWT,180.,R,10.1,N,05.2,M,018.7,K*7F')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(3.1415, 0.005)
+    })
+
+    it('speed & direction data (#3)', () => { // 190R = 170L
+	const delta = new Parser().parse('$IIVWT,190.,R,10.1,N,05.2,M,018.7,K*7E')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(-2.967, 0.005)
+    })
+
+    it('speed & direction data (#4)', () => { 
+	const delta = new Parser().parse('$IIVWT,170.,L,10.1,N,05.2,M,018.7,K*6E')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(-2.967, 0.005)
+    })
+
+    it('speed & direction data (#5)', () => { // 170 + 360 = 530
+	const delta = new Parser().parse('$IIVWT,530.,L,10.1,N,05.2,M,018.7,K*6E')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(-2.967, 0.005)
+    })
+
+    it('missing speed data (#1)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,,N,05.2,M,018.7,*20')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('missing speed data (#2)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,N,,,018.7,K*21')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(5.2, 0.05)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('missing speed data (#3)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,N,,,,K*01')
+	
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(5.2, 0.05)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('missing direction data (#1)', () => {
+	const delta = new Parser().parse('$IIVWT,,R,10.1,N,,,,K*1C')
+	
+	should.equal(delta,null);
+    })
+
+    it('missing direction data (#2)', () => {
+	const delta = new Parser().parse('$IIVWT,0.0,,10.1,N,,,,K*60')
+	
+	should.equal(delta,null);
+    })
+
+    it('improper direction designator (#1)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,r,10.1,N,05.2,M,018.7,K*55')
+
+	should.equal(delta,null);
+    })
+
+    it('improper speed designator (#1)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,X,05.2,M,018.7,X*70')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.equal(5.2)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('improper speed designator (#2)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,N,05.2,X,018.7,K*60')
+
+	delta.updates[0].values[0].path.should.equal('environment.wind.speedTrue')
+	delta.updates[0].values[0].value.should.be.closeTo(5.2, 0.05)
+	delta.updates[0].values[1].path.should.equal('environment.wind.angleTrueWater')
+	delta.updates[0].values[1].value.should.be.closeTo(0.523599, 0.005)
+    })
+
+    it('improper speed designator (#3)', () => {
+	const delta = new Parser().parse('$IIVWT,030.,R,10.1,X,05.2,X,018.7,X*65')
+
+	should.equal(delta,null);
+    })
+
+    it('Doesn\'t choke on empty sentences', () => {
+	const delta = new Parser().parse('$IIVWT,,,,*55')
+	should.equal(delta, null)
+    })
+
+})