Added a class diagram for orbit determination parameters.

src/design/orbit-determination-parameters-class-diagram.puml

+' Copyright 2002-2015 CS Systèmes d'Information
+' Licensed to CS Systèmes d'Information (CS) under one or more
+' contributor license agreements.  See the NOTICE file distributed with
+' this work for additional information regarding copyright ownership.
+' CS licenses this file to You 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.
+ 
+@startuml
+
+  skinparam svek                  true
+  skinparam ClassBackgroundColor  #F3EFEB/CCC9C5
+  skinparam ClassArrowColor       #691616
+  skinparam ClassBorderColor      #691616
+  skinparam NoteBackgroundColor   #F3EFEB
+  skinparam NoteBorderColor       #691616
+  skinparam NoteFontColor         #691616
+  skinparam ClassFontSize         11
+  skinparam PackageFontSize       12
+
+  package org.orekit #ECEBD8 {
+
+    package estimation #DDEBD8 {
+
+      package leastsquares #CEEBD8 { 
+        class BatchLSEstimator
+      }
+
+      abstract class Parameter {
+        +getName()
+        +getDimension()
+        +[is|set]Estimated()
+        +[get|set]Value()
+        #valueChanged()
+      }
+    
+      BatchLSEstimator --> Parameter : change value
+
+      package measurement #CEEBD8 {
+        interface Measurement {
+          +getSupportedParameters()
+        }
+        class GroundStation {
+          #valueChanged()
+        }
+        Range     ..|> Measurement
+        RangeRate ..|> Measurement
+        GroundStation "1" <--* Range
+        GroundStation "1" <--* RangeRate
+        Parameter <|-- GroundStation : position offset
+      }
+
+    }
+
+    package frames #DDEBD8 {
+      class TopocentricFrame
+      GroundStation *--> TopocentricFrame : updated on parameter change
+    }
+
+    
+  }
+
+
+@enduml