From: curt <curt>
Date: Tue, 30 May 2000 16:49:44 +0000 (+0000)
Subject: Updates [hack] from David Megginson so VOR reception range scales with
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=2e08c972048c9d0ee321d0ad960dadd5c21a573f;p=flightgear.git

Updates [hack] from David Megginson so VOR reception range scales with
altitude.
---

diff --git a/src/Cockpit/radiostack.cxx b/src/Cockpit/radiostack.cxx
index 80db998ed..e6c048db0 100644
--- a/src/Cockpit/radiostack.cxx
+++ b/src/Cockpit/radiostack.cxx
@@ -27,6 +27,30 @@
 
 #include "radiostack.hxx"
 
+/**
+ * Boy, this is ugly!  Make the VOR range vary by altitude difference.
+ */
+static inline double
+kludgeRange (double stationElev, double aircraftElev, double nominalRange)
+{
+				// Assume that the nominal range (usually
+				// 50nm) applies at a 5,000 ft difference.
+				// Just a wild guess!
+  double factor = ((aircraftElev*METER_TO_FEET) - stationElev) / 5000.0;
+  double range = fabs(nominalRange * factor);
+
+				// Clamp the range to keep it sane; for
+				// now, never less than 25% or more than
+				// 500% of nominal range.
+  if (range < nominalRange/4.0) {
+    range = nominalRange/4.0;
+  } else if (range > nominalRange*5.0) {
+    range = nominalRange*5.0;
+  }
+
+  return range;
+}
+
 
 FGRadioStack *current_radiostack;
 
@@ -205,7 +229,7 @@ void FGRadioStack::search( double lon, double lat, double elev ) {
 	nav1_loclon = nav.get_lon();
 	nav1_loclat = nav.get_lat();
 	nav1_elev = nav.get_elev();
-	nav1_effective_range = nav.get_range();
+	nav1_effective_range = kludgeRange(nav1_elev, elev, nav.get_range());
 	nav1_target_gs = 0.0;
 	nav1_radial = nav1_sel_radial;
 	nav1_x = nav1_dme_x = nav.get_x();
@@ -251,7 +275,7 @@ void FGRadioStack::search( double lon, double lat, double elev ) {
 	nav2_loclon = nav.get_lon();
 	nav2_loclat = nav.get_lat();
 	nav2_elev = nav.get_elev();
-	nav2_effective_range = nav.get_range();
+	nav2_effective_range = kludgeRange(nav2_elev, elev, nav.get_range());
 	nav2_target_gs = 0.0;
 	nav2_radial = nav2_sel_radial;
 	nav2_x = nav2_dme_x = nav.get_x();
@@ -271,7 +295,7 @@ void FGRadioStack::search( double lon, double lat, double elev ) {
 	adf_lon = nav.get_lon();
 	adf_lat = nav.get_lat();
 	adf_elev = nav.get_elev();
-	adf_effective_range = nav.get_range();
+	adf_effective_range = kludgeRange(adf_elev, elev, nav.get_range());
 	adf_x = nav.get_x();
 	adf_y = nav.get_y();
 	adf_z = nav.get_z();
diff --git a/src/Navaids/navlist.cxx b/src/Navaids/navlist.cxx
index 432d23c67..75f15ee90 100644
--- a/src/Navaids/navlist.cxx
+++ b/src/Navaids/navlist.cxx
@@ -131,7 +131,7 @@ bool FGNavList::query( double lon, double lat, double elev, double freq,
 	// cout << "  dist = " << sqrt(d)
 	//      << "  range = " << current->get_range() * NM_TO_METER << endl;
 	if ( d < (current->get_range() * NM_TO_METER 
-		  * current->get_range() * NM_TO_METER) ) {
+		  * current->get_range() * NM_TO_METER * 5.0) ) {
 	    // cout << "matched = " << current->get_ident() << endl;
 	    *n = *current;
 	    return true;