diff --git a/ontology/saref4auto.ttl b/ontology/saref4auto.ttl
index e1397c47f8b9bf6733b1091666f9ffbba8199b82..402d0a67202586d30dc2e4eff77dd9bad0f1bda5 100644
--- a/ontology/saref4auto.ttl
+++ b/ontology/saref4auto.ttl
@@ -282,7 +282,7 @@ saref:relatesToProperty rdf:type owl:ObjectProperty ;
 :hasConfidence rdf:type owl:ObjectProperty ;
                owl:inverseOf :isConfidenceOf ;
                rdfs:range :Confidence ;
-               rdfs:comment "A relation between an estimated measurement (saref:Measurement class) and its confidence (s4auto:Confidence)"@en ;
+               rdfs:comment "A relation between an estimated measurement (saref:Observation class) and its confidence (s4auto:Confidence)"@en ;
                rdfs:label "hasConfidence"@en .
 
 
@@ -505,7 +505,7 @@ saref:relatesToProperty rdf:type owl:ObjectProperty ;
 
 ###  https://saref.etsi.org/saref4auto/isConfidenceOf
 :isConfidenceOf rdf:type owl:ObjectProperty ;
-                rdfs:comment "A relation between the confidence (s4auto:Confidence class) of an estimated measurement and this measurement (saref:Measurement class)"@en ;
+                rdfs:comment "A relation between the confidence (s4auto:Confidence class) of an estimated measurement and this measurement (saref:Observation class)"@en ;
                 rdfs:label "isConfidenceOf"@en .
 
 
@@ -754,7 +754,7 @@ saref:Device rdf:type owl:Class ;
                              ] ,
                              [ rdf:type owl:Restriction ;
                                owl:onProperty saref:makesMeasurement ;
-                               owl:allValuesFrom saref:Measurement
+                               owl:allValuesFrom saref:Observation
                              ] ,
                              [ rdf:type owl:Restriction ;
                                owl:onProperty saref:measuresProperty ;
@@ -780,48 +780,6 @@ saref:FeatureOfInterest rdf:type owl:Class ;
                         rdfs:label "FeatureOfInterest"@en .
 
 
-###  https://saref.etsi.org/core/Measurement
-saref:Measurement rdf:type owl:Class ;
-                  rdfs:subClassOf [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:measurementMadeBy ;
-                                    owl:someValuesFrom saref:Device
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty :hasConfidence ;
-                                    owl:someValuesFrom :Confidence
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:isMeasuredIn ;
-                                    owl:allValuesFrom saref:UnitOfMeasure
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:relatesToProperty ;
-                                    owl:allValuesFrom saref:Property
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:isMeasuredIn ;
-                                    owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
-                                    owl:onClass saref:UnitOfMeasure
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:relatesToProperty ;
-                                    owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
-                                    owl:onClass saref:Property
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:hasTimestamp ;
-                                    owl:allValuesFrom xsd:dateTime
-                                  ] ,
-                                  [ rdf:type owl:Restriction ;
-                                    owl:onProperty saref:hasValue ;
-                                    owl:qualifiedCardinality "1"^^xsd:nonNegativeInteger ;
-                                    owl:onDataRange xsd:float
-                                  ] ;
-                  rdfs:comment "Represents the measured value made over a property. It is also linked to the unit of measure in which the value is expressed and the timestamp of the measurement."@en ;
-                  rdfs:isDefinedBy saref: ;
-                  rdfs:label "Measurement"@en .
-
-
 ###  https://saref.etsi.org/core/Property
 saref:Property rdf:type owl:Class ;
                rdfs:subClassOf [ rdf:type owl:Restriction ;
@@ -834,7 +792,7 @@ saref:Property rdf:type owl:Class ;
                                ] ,
                                [ rdf:type owl:Restriction ;
                                  owl:onProperty saref:relatesToMeasurement ;
-                                 owl:allValuesFrom saref:Measurement
+                                 owl:allValuesFrom saref:Observation
                                ] ;
                rdfs:comment "Anything that can be sensed, measured or controlled by a device (measured by a sensor, controlled by an actuator) ."@en ;
                rdfs:isDefinedBy <https://saref.etsi.org/core> ;
@@ -1089,7 +1047,7 @@ saref:UnitOfMeasure rdf:type owl:Class ;
                                        ] ,
                                        [ rdf:type owl:Restriction ;
                                          owl:onProperty :usesMeasurement ;
-                                         owl:someValuesFrom saref:Measurement
+                                         owl:someValuesFrom saref:Observation
                                        ] ,
                                        [ rdf:type owl:Restriction ;
                                          owl:onProperty s4syst:subSystemOf ;
@@ -1588,7 +1546,7 @@ saref:UnitOfMeasure rdf:type owl:Class ;
                   rdfs:subClassOf saref:Actuator ,
                                   [ rdf:type owl:Restriction ;
                                     owl:onProperty :usesMeasurement ;
-                                    owl:someValuesFrom saref:Measurement
+                                    owl:someValuesFrom saref:Observation
                                   ] ;
                   rdfs:comment "Devices deployed along the road that produce signals based on road side sensor data measurements. Types of road side actuators that are relevant are devices such as traffic light controllers changing from red to green based on detected vehicles."@en ;
                   rdfs:label """RoadSideActuator