diff --git a/src/main/java/org/orekit/rugged/atmosphericrefraction/ConstantRefractionLayer.java b/src/main/java/org/orekit/rugged/atmosphericrefraction/ConstantRefractionLayer.java
new file mode 100644
index 0000000000000000000000000000000000000000..7baf32c2e5ccce065ffed27c49ffd71d70125b70
--- /dev/null
+++ b/src/main/java/org/orekit/rugged/atmosphericrefraction/ConstantRefractionLayer.java
@@ -0,0 +1,40 @@
+/* Copyright 2013-2016 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.
+ */
+package org.orekit.rugged.atmosphericrefraction;
+
+/**
+ * Class that represents a constant refraction layer to be used with {@link MultiLayerModel}.
+ *
+ * @author Sergio Esteves
+ */
+public class ConstantRefractionLayer {
+    private double lowestAltitude;
+    private double refractionIndex;
+
+    public ConstantRefractionLayer(double lowestAltitude, double refractionIndex) {
+        this.lowestAltitude = lowestAltitude;
+        this.refractionIndex = refractionIndex;
+    }
+
+    public double getLowestAltitude() {
+        return lowestAltitude;
+    }
+
+    public double getRefractionIndex() {
+        return refractionIndex;
+    }
+}
diff --git a/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java b/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
index f6b79e7aa00f38e5c51f55c553016edb0353c147..7212f5c497f5f2584c90d887638f593b0aeb16d9 100644
--- a/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
+++ b/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
@@ -19,26 +19,14 @@ package org.orekit.rugged.atmosphericrefraction;
 import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
 import org.apache.commons.math3.util.FastMath;
 import org.orekit.bodies.GeodeticPoint;
-import org.orekit.bodies.OneAxisEllipsoid;
 import org.orekit.errors.OrekitException;
-import org.orekit.frames.FramesFactory;
 import org.orekit.rugged.errors.RuggedException;
 import org.orekit.rugged.intersection.IntersectionAlgorithm;
-import org.orekit.rugged.intersection.duvenhage.MinMaxTreeTile;
-import org.orekit.rugged.intersection.duvenhage.MinMaxTreeTileFactory;
-import org.orekit.rugged.raster.Tile;
-import org.orekit.rugged.raster.TilesCache;
 import org.orekit.rugged.utils.ExtendedEllipsoid;
 import org.orekit.rugged.utils.NormalizedGeodeticPoint;
-import org.orekit.utils.Constants;
-import org.orekit.utils.IERSConventions;
 
 import java.util.ArrayList;
-import java.util.Collections;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
-import java.util.TreeMap;
 
 /**
  * Multi layer model for atmospheric refraction.
@@ -138,21 +126,3 @@ public class MultiLayerModel implements AtmosphericRefraction {
         }
     }
 }
-
-class ConstantRefractionLayer {
-    private double lowestAltitude;
-    private double refractionIndex;
-
-    public ConstantRefractionLayer(double lowestAltitude, double refractionIndex) {
-        this.lowestAltitude = lowestAltitude;
-        this.refractionIndex = refractionIndex;
-    }
-
-    public double getLowestAltitude() {
-        return lowestAltitude;
-    }
-
-    public double getRefractionIndex() {
-        return refractionIndex;
-    }
-}