diff --git a/src/Cockpit/navcom.cxx b/src/Cockpit/navcom.cxx
index 3f8f21aee..1fe7b3882 100644
--- a/src/Cockpit/navcom.cxx
+++ b/src/Cockpit/navcom.cxx
@@ -29,6 +29,7 @@
 
 #include <simgear/compiler.h>
 #include <simgear/math/sg_random.h>
+#include <simgear/math/vector.hxx>
 
 #include <Aircraft/aircraft.hxx>
 #include <Navaids/ilslist.hxx>
@@ -325,9 +326,20 @@ FGNavCom::update(double dt)
 	nav_loc_dist = aircraft.distance3D( station );
 
 	if ( nav_has_gs ) {
-	    station = Point3D( nav_gs_x, nav_gs_y, nav_gs_z );
-	    nav_gs_dist = aircraft.distance3D( station );
-            // wgs84 heading to glide slope
+            // find closest distance to the gs base line
+            sgdVec3 p;
+            sgdSetVec3( p, aircraft.x(), aircraft.y(), aircraft.z() );
+            sgdVec3 p0;
+            sgdSetVec3( p0, nav_gs_x, nav_gs_y, nav_gs_z );
+            double dist = sgdClosestPointToLineDistSquared( p, p0,
+                                                            gs_base_vec );
+            nav_gs_dist = sqrt( dist );
+            // cout << nav_gs_dist;
+
+            Point3D tmp( nav_gs_x, nav_gs_y, nav_gs_z );
+            // cout << " (" << aircraft.distance3D( tmp ) << ")" << endl;
+
+            // wgs84 heading to glide slope (to determine sign of distance)
             geo_inverse_wgs_84( elev,
                                 lat * SGD_RADIANS_TO_DEGREES,
                                 lon * SGD_RADIANS_TO_DEGREES, 
@@ -491,6 +503,22 @@ void FGNavCom::search()
 	    nav_gs_y = ils->get_gs_y();
 	    nav_gs_z = ils->get_gs_z();
 
+            // derive GS baseline
+            double tlon, tlat, taz;
+            geo_direct_wgs_84 ( 0.0, nav_gslat, nav_gslon, nav_radial + 90,  
+                                100.0, &tlat, &tlon, &taz );
+            cout << nav_gslon << "," << nav_gslat << "  "
+                 << tlon << "," << tlat << "  (" << nav_elev << ")" << endl;
+            Point3D p1 = sgGeodToCart( Point3D(tlon*SGD_DEGREES_TO_RADIANS,
+                                               tlat*SGD_DEGREES_TO_RADIANS,
+                                               nav_elev*SG_FEET_TO_METER) );
+            cout << nav_gs_x << "," << nav_gs_y << "," << nav_gs_z << endl;
+            cout << p1 << endl;
+            sgdSetVec3( gs_base_vec,
+                        p1.x()-nav_gs_x, p1.y()-nav_gs_y, p1.z()-nav_gs_z );
+            cout << gs_base_vec[0] << "," << gs_base_vec[1] << ","
+                 << gs_base_vec[2] << endl;
+
 	    if ( globals->get_soundmgr()->exists( nav_fx_name ) ) {
 		globals->get_soundmgr()->remove( nav_fx_name );
 	    }
@@ -625,7 +653,8 @@ double FGNavCom::get_nav_gs_needle_deflection() const {
 	double x = nav_gs_dist;
 	double y = (fgGetDouble("/position/altitude-ft") - nav_elev)
             * SG_FEET_TO_METER;
-	double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
+        // cout << "dist = " << x << " height = " << y << endl;
+	double angle = asin( y / x ) * SGD_RADIANS_TO_DEGREES;
 	return (nav_target_gs - angle) * 5.0;
     } else {
 	return 0.0;
diff --git a/src/Cockpit/navcom.hxx b/src/Cockpit/navcom.hxx
index 33a01dcf5..960d8cdbc 100644
--- a/src/Cockpit/navcom.hxx
+++ b/src/Cockpit/navcom.hxx
@@ -102,6 +102,7 @@ class FGNavCom : public FGSubsystem
     double nav_gs_x;
     double nav_gs_y;
     double nav_gs_z;
+    sgdVec3 gs_base_vec;
     double nav_gs_dist;
     double nav_gs_dist_signed;
     SGTimeStamp prev_time;
diff --git a/src/Navaids/ils.hxx b/src/Navaids/ils.hxx
index 953132d9f..a9b7da167 100644
--- a/src/Navaids/ils.hxx
+++ b/src/Navaids/ils.hxx
@@ -179,7 +179,9 @@ operator >> ( istream& in, FGILS& i )
     // generate cartesian coordinates
     Point3D geod, cart;
 
-    geod = Point3D( i.loclon * SGD_DEGREES_TO_RADIANS, i.loclat * SGD_DEGREES_TO_RADIANS, i.gselev );
+    geod = Point3D( i.loclon * SGD_DEGREES_TO_RADIANS,
+                    i.loclat * SGD_DEGREES_TO_RADIANS,
+                    i.gselev * SG_FEET_TO_METER );
     cart = sgGeodToCart( geod );
     i.x = cart.x();
     i.y = cart.y();
@@ -190,7 +192,9 @@ operator >> ( istream& in, FGILS& i )
     } else {
 	i.has_gs = true;
 
-	geod = Point3D( i.gslon * SGD_DEGREES_TO_RADIANS, i.gslat * SGD_DEGREES_TO_RADIANS, i.gselev );
+	geod = Point3D( i.gslon * SGD_DEGREES_TO_RADIANS,
+                        i.gslat * SGD_DEGREES_TO_RADIANS,
+                        i.gselev * SG_FEET_TO_METER );
 	cart = sgGeodToCart( geod );
 	i.gs_x = cart.x();
 	i.gs_y = cart.y();
@@ -203,7 +207,9 @@ operator >> ( istream& in, FGILS& i )
     } else {
 	i.has_dme = true;
 
-	geod = Point3D( i.dmelon * SGD_DEGREES_TO_RADIANS, i.dmelat * SGD_DEGREES_TO_RADIANS, i.gselev);
+	geod = Point3D( i.dmelon * SGD_DEGREES_TO_RADIANS,
+                        i.dmelat * SGD_DEGREES_TO_RADIANS,
+                        i.gselev * SG_FEET_TO_METER );
 	cart = sgGeodToCart( geod );
 	i.dme_x = cart.x();
 	i.dme_y = cart.y();