diff --git a/src/blackmisc/simulation/interpolatorlinear.h b/src/blackmisc/simulation/interpolatorlinear.h
index e9355bace..56ee024cb 100644
--- a/src/blackmisc/simulation/interpolatorlinear.h
+++ b/src/blackmisc/simulation/interpolatorlinear.h
@@ -48,6 +48,9 @@ namespace BlackMisc
                 //! @}
 
                 //! Perform the interpolation
+                //! \param situation situation used as a base for interpolation. Contains for example the already interpolated PBH.
+                //! \param interpolateGndFactor whether to interpolate the GND factor.
+                //! \return \p situation with interpolated position and altitude, updated timestamp and possibly interpolated GND factor
                 Aviation::CAircraftSituation interpolatePositionAndAltitude(const Aviation::CAircraftSituation &situation, bool interpolateGndFactor) const;
 
                 //! Old situation
diff --git a/src/blackmisc/simulation/interpolatorspline.h b/src/blackmisc/simulation/interpolatorspline.h
index eab803b63..1d058e7cf 100644
--- a/src/blackmisc/simulation/interpolatorspline.h
+++ b/src/blackmisc/simulation/interpolatorspline.h
@@ -66,6 +66,9 @@ namespace BlackMisc::Simulation
             CInterpolant(const PosArray &pa, const PhysicalQuantities::CLengthUnit &altitudeUnit, const CInterpolatorPbh &pbh);
 
             //! Perform the interpolation
+            //! \param situation situation used as a base for interpolation. Contains for example the already interpolated PBH.
+            //! \param interpolateGndFactor whether to interpolate the GND factor.
+            //! \return \p situation with interpolated position and altitude, updated timestamp and possibly interpolated GND factor
             Aviation::CAircraftSituation interpolatePositionAndAltitude(const Aviation::CAircraftSituation &currentSituation, bool interpolateGndFactor) const;
 
             //! Set the time values