diff --git a/pgns/129038.js b/pgns/129038.js
index ede74b4..48143c3 100644
--- a/pgns/129038.js
+++ b/pgns/129038.js
@@ -56,6 +56,12 @@ module.exports = [
   },
   {
     context: getMmsiContext
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'A'
+    }
   }
 ]
 
diff --git a/pgns/129039.js b/pgns/129039.js
index b81382d..570d0a0 100644
--- a/pgns/129039.js
+++ b/pgns/129039.js
@@ -34,5 +34,11 @@ module.exports = [
   },
   {
     context: getMmsiContext
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'B'
+    }
   }
 ]
diff --git a/pgns/129040.js b/pgns/129040.js
index 5f56e24..8236d45 100644
--- a/pgns/129040.js
+++ b/pgns/129040.js
@@ -84,5 +84,11 @@ module.exports = [
   },
   {
     context: getMmsiContext
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'B'
+    }
   }
 ]
diff --git a/pgns/129041.js b/pgns/129041.js
index 028810f..76bd7fe 100644
--- a/pgns/129041.js
+++ b/pgns/129041.js
@@ -90,6 +90,12 @@ module.exports = [
     context: function (n2k) {
       return n2k.fields['User ID'] ? 'atons.urn:mrn:imo:mmsi:' + n2k.fields['User ID'] : undefined
     }
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'ATON'
+    }
   }
 ]
 
diff --git a/pgns/129793.js b/pgns/129793.js
index 5f349ce..f5f71b4 100644
--- a/pgns/129793.js
+++ b/pgns/129793.js
@@ -31,5 +31,11 @@ module.exports = [
     context: function (n2k) {
       return n2k.fields['User ID'] ? 'shore.basestations.urn:mrn:imo:mmsi:' + n2k.fields['User ID'] : undefined
     }
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'BASE'
+    }
   }
 ]
diff --git a/pgns/129798.js b/pgns/129798.js
index ebdd014..0360f00 100644
--- a/pgns/129798.js
+++ b/pgns/129798.js
@@ -35,5 +35,11 @@ module.exports = [
     context: function (n2k) {
       return n2k.fields['User ID'] ? 'sar.urn:mrn:imo:mmsi:' + n2k.fields['User ID'] : undefined
     }
+  },
+  {
+    node: 'sensors.ais.class',
+    value: function (n2k) {
+      return 'SAR'
+    }
   }
 ]
diff --git a/test/129038_ais_class_a.js b/test/129038_ais_class_a.js
index aaedd90..2d029cc 100644
--- a/test/129038_ais_class_a.js
+++ b/test/129038_ais_class_a.js
@@ -1,4 +1,5 @@
 var chai = require('chai')
+const { assertSensorClass } = require('./ais_utils')
 chai.Should()
 chai.use(require('chai-things'))
 chai.use(require('@signalk/signalk-schema').chaiModule)
@@ -26,10 +27,15 @@ describe('129038 Class A Update', function () {
     tree.should.have.nested.property('navigation.headingTrue.value', 153.0)
     tree.should.have.nested.property('navigation.state')
     tree.should.have.nested.property('navigation.state.value', 'motoring')
+
+    //TODO remove when sensors.ais.class is in schema
+    delete tree.sensors.ais
+
     tree.should.be.validSignalKVesselIgnoringIdentity
     var delta = mapper.toDelta(msg)
     delta.updates.length.should.equal(1)
     delta.context.should.equal('vessels.urn:mrn:imo:mmsi:230982000')
+    assertSensorClass(delta, 'A')
   })
 
   it('special maneuver converts', function () {
diff --git a/test/129039_ais_class_b.js b/test/129039_ais_class_b.js
index 746a4b7..0cb4fdc 100644
--- a/test/129039_ais_class_b.js
+++ b/test/129039_ais_class_b.js
@@ -5,6 +5,7 @@ chai.use(require('chai-things'))
 chai.use(require('@signalk/signalk-schema').chaiModule)
 
 var mapper = require('./testMapper')
+const { assertSensorClass } = require('./ais_utils')
 
 describe('129039 Class B Update', function () {
   it('complete self sentence converts', function () {
@@ -23,10 +24,15 @@ describe('129039 Class B Update', function () {
     tree.navigation.position.value.latitude.should.equal(60.03951)
     tree.should.have.nested.property('navigation.headingTrue')
     tree.should.have.nested.property('navigation.headingTrue.value', 153.0)
+
+    //TODO remove when sensors.ais.class is in schema
+    delete tree.sensors.ais
+
     tree.should.be.validSignalKVesselIgnoringIdentity
     var delta = mapper.toDelta(msg)
     delta.updates.length.should.equal(1)
     assert.equal(delta.context, 'vessels.urn:mrn:imo:mmsi:230035780')
+    assertSensorClass(delta, 'B')
   })
 
   it('complete other sentence converts', function () {
@@ -43,9 +49,14 @@ describe('129039 Class B Update', function () {
     tree.should.have.nested.property('navigation.speedOverGround.value', 2.88)
     tree.navigation.position.value.longitude.should.equal(-76.1882515)
     tree.navigation.position.value.latitude.should.equal(39.1087383)
+
+    //TODO remove when sensors.ais.class is in schema
+    delete tree.sensors.ais
+
     tree.should.be.validSignalKVesselIgnoringIdentity
     var delta = mapper.toDelta(msg)
     delta.updates.length.should.equal(1)
     delta.context.should.equal('vessels.urn:mrn:imo:mmsi:235087238')
+    assertSensorClass(delta, 'B')
   })
 })
diff --git a/test/129040_class_b_extended.js b/test/129040_class_b_extended.js
index 0febb4b..18a095d 100644
--- a/test/129040_class_b_extended.js
+++ b/test/129040_class_b_extended.js
@@ -1,4 +1,5 @@
 var chai = require('chai')
+const { assertSensorClass } = require('./ais_utils')
 chai.Should()
 chai.use(require('chai-things'))
 chai.use(require('@signalk/signalk-schema').chaiModule)
@@ -15,6 +16,8 @@ describe('129040 AIS Class B Extended Position Repeat', function () {
     delta.context.should.equal('vessels.urn:mrn:imo:mmsi:230939100')
     delta.updates[0].values[0].path.should.equal('')
     delta.updates[0].values[0].value.name.should.equal('RESCUE RAUTAUOMA')
+    assertSensorClass(delta, 'B')
+    
     var tree = mapper.toNested(msg)
     tree.should.have.nested.property('design.length.value.overall', 16.0)
     tree.should.have.nested.property('design.aisShipType.value.id', 51)
@@ -37,6 +40,10 @@ describe('129040 AIS Class B Extended Position Repeat', function () {
     tree.should.have.nested.property('sensors.ais.fromBow.value', 9.0)
     tree.should.have.nested.property('sensors.ais.fromCenter.value', 0)
     delete tree.design.aisShipType
+
+    //TODO remove when sensors.ais.class is in schema
+    delete tree.sensors.ais
+
     tree.should.be.validSignalKVesselIgnoringIdentity
   })
 })
diff --git a/test/129793_ais_base_station_data.js b/test/129793_ais_base_station_data.js
index 3bf1caa..9e12bf5 100644
--- a/test/129793_ais_base_station_data.js
+++ b/test/129793_ais_base_station_data.js
@@ -1,4 +1,5 @@
 var chai = require('chai')
+const { assertSensorClass } = require('./ais_utils')
 chai.Should()
 chai.use(require('chai-things'))
 chai.use(require('@signalk/signalk-schema').chaiModule)
@@ -35,7 +36,7 @@ describe('129793 AIS UTC and Date Report (Base Station)', function () {
     console.log(JSON.stringify(delta, null, 2))
     delta.updates.length.should.equal(1)
     const values = delta.updates[0].values
-    values.length.should.equal(2)
+    values.length.should.equal(3)
     values[0].path.should.equal('navigation.position')
     values[0].value.should.deep.equal({
       longitude: 4.5183933,
@@ -46,5 +47,6 @@ describe('129793 AIS UTC and Date Report (Base Station)', function () {
       mmsi: '2442103'
     })
     delta.context.should.equal('shore.basestations.urn:mrn:imo:mmsi:2442103')
+    assertSensorClass(delta, 'BASE')
   })
 })
diff --git a/test/129794_ais_class_a_static_data.js b/test/129794_ais_class_a_static_data.js
index 0ef28ed..244303d 100644
--- a/test/129794_ais_class_a_static_data.js
+++ b/test/129794_ais_class_a_static_data.js
@@ -32,6 +32,7 @@
  */
 
 const chai = require('chai')
+const { assertSensorClass } = require('./ais_utils')
 const expect = chai.expect
 chai.Should()
 chai.use(require('chai-things'))
@@ -47,7 +48,7 @@ describe('129794 AIS Class A Static and Voyage Related Data', function () {
     var delta = mapper.toDelta(msg)
     delta.updates.length.should.equal(1)
     delta.context.should.equal('vessels.urn:mrn:imo:mmsi:356307000')
-    delta.updates[0].values.find(pathValue => pathValue.path === 'sensors.ais.class').value.should.equal('A')
+    assertSensorClass(delta, 'A')
 
     const valuesWithEmptyPath = delta.updates[0].values.filter(pathValue => pathValue.path === '')
     valuesWithEmptyPath.length.should.equal(3)
diff --git a/test/129798_sar.js b/test/129798_sar.js
index 6527924..01d8bf1 100644
--- a/test/129798_sar.js
+++ b/test/129798_sar.js
@@ -1,4 +1,5 @@
 var chai = require('chai')
+const { assertSensorClass } = require('./ais_utils')
 chai.Should()
 chai.use(require('chai-things'))
 chai.use(require('@signalk/signalk-schema').chaiModule)
@@ -13,6 +14,7 @@ describe('129798 AIS SAR Aircraft Position Report', function () {
     var delta = mapper.toDelta(msg)
     delta.updates.length.should.equal(1)
     delta.context.should.equal('sar.urn:mrn:imo:mmsi:100046')
+    assertSensorClass(delta, 'SAR')
     var tree = mapper.toNested(msg)
     tree.navigation.position.value.longitude.should.equal(-75.8338099)
     tree.navigation.position.value.latitude.should.equal(39.6475617)
@@ -21,7 +23,10 @@ describe('129798 AIS SAR Aircraft Position Report', function () {
       2.227
     )
     tree.should.have.nested.property('navigation.speedOverGround.value', 694.4)
-    console.log(JSON.stringify(tree))
+
+    //TODO remove when sensors.ais.class is in schema
+    delete tree.sensors.ais
+
     tree.should.be.validSignalKVesselIgnoringIdentity
   })
 })
diff --git a/test/ais_utils.js b/test/ais_utils.js
new file mode 100644
index 0000000..00b3b8a
--- /dev/null
+++ b/test/ais_utils.js
@@ -0,0 +1,6 @@
+module.exports = {
+  assertSensorClass: (delta, theClass) =>
+    delta.updates[0].values
+      .find((pathValue) => pathValue.path === "sensors.ais.class")
+      .value.should.equal(theClass)
+}