diff --git a/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java b/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
index ab5ad84e489dd9a7cb0997c424d2312acff8b38b..ca57ed5f981788733d4a02f3fa657f365d3b43d1 100644
--- a/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
+++ b/src/main/java/org/orekit/rugged/atmosphericrefraction/MultiLayerModel.java
@@ -8,9 +8,23 @@ import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
  */
 public class MultiLayerModel implements AtmosphericRefraction {
 
+    private static final double KARMA_LINE = 1000000;
+    private static final double LAYER_SIZE = KARMA_LINE * 0.25;
+
+    private int numberOfLayers = 1;
+
+    public MultiLayerModel() {
+    }
+
+    public MultiLayerModel(int numberOfLayers) {
+        this.numberOfLayers = numberOfLayers;
+    }
+
     @Override
     public long getDeviation(Vector3D pos, Vector3D los, double altitude) {
 
+        double numberOfCrossedLayers = (KARMA_LINE - altitude) / LAYER_SIZE;
+
 
 
         return 0;