Prepared API for LOS calibration.

src/main/java/org/orekit/rugged/los/LOSBuilder.java

@@ -19,6 +19,8 @@ package org.orekit.rugged.los;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
+import org.apache.commons.math3.geometry.euclidean.threed.FieldVector3D;
 import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
 import org.orekit.time.AbsoluteDate;
 
@@ -115,7 +117,7 @@ public class LOSBuilder {
     private static class FixedLOS implements TimeDependentLOS {
 
         /** Fixed direction for los. */
-        private final Vector3D[]  los;
+        private final Vector3D[] los;
 
         /** Simple constructor.
          * @param raw raw directions
@@ -146,6 +148,15 @@ public class LOSBuilder {
             return los[index];
         }
 
+        /** {@inheritDoc} */
+        public FieldVector3D<DerivativeStructure> getLOS(final int index, final AbsoluteDate date,
+                                                         final double[] parameters) {
+            // fixed LOS do not depend on any parameters
+            return new FieldVector3D<DerivativeStructure>(new DerivativeStructure(parameters.length, 1, los[index].getX()),
+                                                          new DerivativeStructure(parameters.length, 1, los[index].getY()),
+                                                          new DerivativeStructure(parameters.length, 1, los[index].getZ()));
+        }
+
     }
 
     /** Implement time-dependent LOS by applying all registered transforms at runtime. */
@@ -194,6 +205,16 @@ public class LOSBuilder {
             return los.normalize();
         }
 
+        /** {@inheritDoc} */
+        public FieldVector3D<DerivativeStructure> getLOS(final int index, final AbsoluteDate date,
+                                                         final double[] parameters) {
+            // non-adjustable LOS do not depend on any parameters
+            final Vector3D los = getLOS(index, date);
+            return new FieldVector3D<DerivativeStructure>(new DerivativeStructure(parameters.length, 1, los.getX()),
+                                                          new DerivativeStructure(parameters.length, 1, los.getY()),
+                                                          new DerivativeStructure(parameters.length, 1, los.getZ()));
+        }
+
     }
 
 }

src/main/java/org/orekit/rugged/los/TimeDependentLOS.java

@@ -16,6 +16,8 @@
  */
 package org.orekit.rugged.los;
 
+import org.apache.commons.math3.analysis.differentiation.DerivativeStructure;
+import org.apache.commons.math3.geometry.euclidean.threed.FieldVector3D;
 import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
 import org.orekit.time.AbsoluteDate;
 
@@ -37,4 +39,18 @@ public interface TimeDependentLOS {
      */
     Vector3D getLOS(int index, AbsoluteDate date);
 
+    /** Get the line of sight and its partial derivatives for a given date.
+     * <p>
+     * This method is used for LOS calibration purposes. It allows to compute
+     * the Jacobian matrix of the LOS with respect to the parameters, which
+     * are typically polynomials coefficients representing rotation angles.
+     * These polynomials can be used for example to model thermo-elestic effects.
+     * </p>
+     * @param index los pixel index
+     * @param date date
+     * @param parameters current estimate of the adjusted parameters
+     * @return line of sight, and its first partial derivatives with respect to the parameters
+     */
+    FieldVector3D<DerivativeStructure> getLOS(int index, AbsoluteDate date, double[] parameters);
+
 }