From 258cd292c6638459e7ea1eaa50f1ddf7ac3029b5 Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Sun, 20 Jun 2004 18:58:44 +0000
Subject: [PATCH] When searching for nav records ignore stations > 300nm away.

---
 src/Cockpit/navcom.cxx    |  3 ++-
 src/Navaids/navlist.cxx   | 21 +++++++--------------
 src/Navaids/navrecord.hxx |  7 ++++---
 3 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/src/Cockpit/navcom.cxx b/src/Cockpit/navcom.cxx
index f37a2e741..583bc5d10 100644
--- a/src/Cockpit/navcom.cxx
+++ b/src/Cockpit/navcom.cxx
@@ -613,9 +613,9 @@ void FGNavCom::search()
         gs = globals->get_gslist()->findByFreq(nav_freq, lon, lat, elev);
     }
         
-
     if ( loc != NULL ) {
 	nav_id = loc->get_ident();
+        // cout << "localizer = " << nav_id << endl;
 	nav_valid = true;
 	if ( last_nav_id != nav_id || last_nav_vor ) {
 	    nav_trans_ident = loc->get_trans_ident();
@@ -701,6 +701,7 @@ void FGNavCom::search()
 	}
     } else if ( nav != NULL ) {
 	nav_id = nav->get_ident();
+        // cout << "nav = " << nav_id << endl;
 	nav_valid = true;
 	if ( last_nav_id != nav_id || !last_nav_vor ) {
 	    last_nav_id = nav_id;
diff --git a/src/Navaids/navlist.cxx b/src/Navaids/navlist.cxx
index f8aab3e0d..8b8aabd10 100644
--- a/src/Navaids/navlist.cxx
+++ b/src/Navaids/navlist.cxx
@@ -182,31 +182,24 @@ FGNavRecord *FGNavList::findNavFromList( const Point3D &aircraft,
 {
     FGNavRecord *nav = NULL;
     Point3D station;
-    double d2;
-    double min_dist = 999999999.0;
+    double dist;
+    double min_dist = FG_NAV_MAX_RANGE * SG_NM_TO_METER;
 
-    // prime the pump with info from stations[0]
-    if ( stations.size() > 0 ) {
-        nav = stations[0];
-	station = Point3D( nav->get_x(), nav->get_y(), nav->get_z());
-	min_dist = aircraft.distance3Dsquared( station );
-    }
-
-    // check if any of the remaining stations are closer
-    for ( unsigned int i = 1; i < stations.size(); ++i ) {
+    // find the closest station within a sensible range (FG_NAV_MAX_RANGE)
+    for ( unsigned int i = 0; i < stations.size(); ++i ) {
 	// cout << "testing " << current->get_ident() << endl;
 	station = Point3D( stations[i]->get_x(),
                            stations[i]->get_y(),
                            stations[i]->get_z() );
 
-	d2 = aircraft.distance3Dsquared( station );
+	dist = aircraft.distance3D( station );
 
 	// cout << "  dist = " << sqrt(d)
 	//      << "  range = " << current->get_range() * SG_NM_TO_METER
         //      << endl;
 
-        if ( d2 < min_dist ) {
-            min_dist = d2;
+        if ( dist < min_dist ) {
+            min_dist = dist;
             nav = stations[i];
         }
     }
diff --git a/src/Navaids/navrecord.hxx b/src/Navaids/navrecord.hxx
index ab1ca85c0..dcd7b36bd 100644
--- a/src/Navaids/navrecord.hxx
+++ b/src/Navaids/navrecord.hxx
@@ -43,9 +43,10 @@
 SG_USING_STD(istream);
 
 
-#define FG_NAV_DEFAULT_RANGE 50
-#define FG_LOC_DEFAULT_RANGE 18
-#define FG_DME_DEFAULT_RANGE 50
+#define FG_NAV_DEFAULT_RANGE 50 // nm
+#define FG_LOC_DEFAULT_RANGE 18 // nm
+#define FG_DME_DEFAULT_RANGE 50 // nm
+#define FG_NAV_MAX_RANGE 300    // nm
 
 
 class FGNavRecord {