]> git.mxchange.org Git - flightgear.git/blobdiff - src/Cockpit/radiostack.cxx
Tweak #includes to use double quotes for local files not <>
[flightgear.git] / src / Cockpit / radiostack.cxx
index 89541efc3969b62111dae73a162882f19a39c098..14b940c03f7d1a6ec31b80e814094ba44283432e 100644 (file)
@@ -29,7 +29,8 @@
 #include <simgear/math/sg_random.h>
 
 #include <Aircraft/aircraft.hxx>
-#include <Main/bfi.hxx>
+#include <ATC/ATCdisplay.hxx>
+//#include <Navaids/atis.hxx>
 #include <Navaids/ilslist.hxx>
 #include <Navaids/mkrbeacons.hxx>
 #include <Navaids/navlist.hxx>
@@ -37,6 +38,9 @@
 
 #include "radiostack.hxx"
 
+#include <string>
+SG_USING_STD(string);
+
 static int nav1_play_count = 0;
 static int nav2_play_count = 0;
 static int adf_play_count = 0;
@@ -57,7 +61,7 @@ static double kludgeRange ( double stationElev, double aircraftElev,
                                // 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 factor = ((aircraftElev*SG_METER_TO_FEET) - stationElev) / 5000.0;
   double range = fabs(nominalRange * factor);
 
                                // Clamp the range to keep it sane; for
@@ -79,15 +83,41 @@ static void fgRadioSearch( void ) {
 }
 
 // Constructor
-FGRadioStack::FGRadioStack() {
-    nav1_radial = 0.0;
-    nav1_dme_dist = 0.0;
-    nav2_radial = 0.0;
-    nav2_dme_dist = 0.0;
-    need_update = true;
-    longitudeVal = fgGetValue("/position/longitude");
-    latitudeVal = fgGetValue("/position/latitude");
-    altitudeVal = fgGetValue("/position/altitude");
+FGRadioStack::FGRadioStack() :
+    lon_node(fgGetNode("/position/longitude-deg", true)),
+    lat_node(fgGetNode("/position/latitude-deg", true)),
+    alt_node(fgGetNode("/position/altitude-ft", true)),
+    need_update(true),
+    comm1_freq(0.0),
+    comm1_alt_freq(0.0),
+    comm2_freq(0.0),
+    comm2_alt_freq(0.0),
+    nav1_freq(0.0),
+    nav1_alt_freq(0.0),
+    nav1_radial(0.0),
+    nav2_freq(0.0),
+    nav2_alt_freq(0.0),
+    nav2_radial(0.0),
+    dme_freq(0.0),
+    dme_dist(0.0),
+    dme_prev_dist(0.0),
+    dme_spd(0.0),
+    dme_ete(0.0),
+    adf_freq(0.0),
+    adf_alt_freq(0.0)
+{
+    SGPath path( globals->get_fg_root() );
+    SGPath term = path;
+    term.append( "Navaids/range.term" );
+    SGPath low = path;
+    low.append( "Navaids/range.low" );
+    SGPath high = path;
+    high.append( "Navaids/range.high" );
+
+    term_tbl = new SGInterpTable( term.str() );
+    low_tbl = new SGInterpTable( low.str() );
+    high_tbl = new SGInterpTable( high.str() );
+    dme_last_time.stamp();
 }
 
 
@@ -95,6 +125,10 @@ FGRadioStack::FGRadioStack() {
 FGRadioStack::~FGRadioStack() 
 {
     unbind();                  // FIXME: should be called externally
+
+    delete term_tbl;
+    delete low_tbl;
+    delete high_tbl;
 }
 
 
@@ -102,22 +136,12 @@ void
 FGRadioStack::init ()
 {
     morse.init();
+    beacon.init();
+    blink.stamp();
 
     search();
     update();
 
-    FGPath path( globals->get_fg_root() );
-    FGPath term = path;
-    term.append( "Navaids/range.term" );
-    FGPath low = path;
-    low.append( "Navaids/range.low" );
-    FGPath high = path;
-    high.append( "Navaids/range.high" );
-
-    term_tbl = new SGInterpTable( term.str() );
-    low_tbl = new SGInterpTable( low.str() );
-    high_tbl = new SGInterpTable( high.str() );
-
     // Search radio database once per second
     global_events.Register( "fgRadioSearch()", fgRadioSearch,
                            fgEVENT::FG_EVENT_READY, 1000);
@@ -127,112 +151,188 @@ void
 FGRadioStack::bind ()
 {
                                // User inputs
-    fgTie("/radios/nav1/frequencies/selected", this,
+    fgTie("/radios/comm[0]/frequencies/selected-mhz", this,
+         &FGRadioStack::get_comm1_freq, &FGRadioStack::set_comm1_freq);
+    fgSetArchivable("/radios/comm[0]/frequencies/selected-mhz");
+    fgTie("/radios/comm[0]/frequencies/standby-mhz", this,
+         &FGRadioStack::get_comm1_alt_freq, &FGRadioStack::set_comm1_alt_freq);
+    fgSetArchivable("/radios/comm[0]/frequencies/standby-mhz");
+     fgTie("/radios/comm[0]/volume", this,
+         &FGRadioStack::get_comm1_vol_btn,
+         &FGRadioStack::set_comm1_vol_btn);
+    fgSetArchivable("/radios/comm[0]/volume");
+    fgTie("/radios/comm[0]/ident", this,
+         &FGRadioStack::get_comm1_ident_btn,
+         &FGRadioStack::set_comm1_ident_btn);
+    fgSetArchivable("/radios/comm[0]/ident");
+
+    fgTie("/radios/comm[1]/frequencies/selected-mhz", this,
+         &FGRadioStack::get_comm2_freq, &FGRadioStack::set_comm2_freq);
+    fgSetArchivable("/radios/comm[0]/frequencies/selected-mhz");
+    fgTie("/radios/comm[1]/frequencies/standby-mhz", this,
+         &FGRadioStack::get_comm2_alt_freq, &FGRadioStack::set_comm2_alt_freq);
+    fgSetArchivable("/radios/comm[0]/frequencies/standby-mhz");
+     fgTie("/radios/comm[1]/volume", this,
+         &FGRadioStack::get_comm2_vol_btn,
+         &FGRadioStack::set_comm2_vol_btn);
+    fgSetArchivable("/radios/comm[0]/volume");
+    fgTie("/radios/comm[1]/ident", this,
+         &FGRadioStack::get_comm2_ident_btn,
+         &FGRadioStack::set_comm2_ident_btn);
+    fgSetArchivable("/radios/comm[1]/ident");
+
+    fgTie("/radios/nav[0]/frequencies/selected-mhz", this,
          &FGRadioStack::get_nav1_freq, &FGRadioStack::set_nav1_freq);
-    fgTie("/radios/nav1/frequencies/standby", this,
+    fgSetArchivable("/radios/nav[0]/frequencies/selected-mhz");
+    fgTie("/radios/nav[0]/frequencies/standby-mhz", this,
          &FGRadioStack::get_nav1_alt_freq, &FGRadioStack::set_nav1_alt_freq);
-    fgTie("/radios/nav1/radials/selected", this,
+    fgSetArchivable("/radios/nav[0]/frequencies/standby-mhz");
+    fgTie("/radios/nav[0]/radials/selected-deg", this,
          &FGRadioStack::get_nav1_sel_radial,
          &FGRadioStack::set_nav1_sel_radial);
-    fgTie("/radios/nav1/volume", this,
+    fgSetArchivable("/radios/nav[0]/radials/selected-deg");
+    fgTie("/radios/nav[0]/volume", this,
          &FGRadioStack::get_nav1_vol_btn,
          &FGRadioStack::set_nav1_vol_btn);
-    fgTie("/radios/nav1/ident", this,
+    fgSetArchivable("/radios/nav[0]/volume");
+    fgTie("/radios/nav[0]/ident", this,
          &FGRadioStack::get_nav1_ident_btn,
          &FGRadioStack::set_nav1_ident_btn);
+    fgSetArchivable("/radios/nav[0]/ident");
 
                                // Radio outputs
-    fgTie("/radios/nav1/radials/actual", this, &FGRadioStack::get_nav1_radial);
-    fgTie("/radios/nav1/to-flag", this, &FGRadioStack::get_nav1_to_flag);
-    fgTie("/radios/nav1/from-flag", this, &FGRadioStack::get_nav1_from_flag);
-    fgTie("/radios/nav1/in-range", this, &FGRadioStack::get_nav1_inrange);
-    fgTie("/radios/nav1/dme/distance", this, &FGRadioStack::get_nav1_dme_dist);
-    fgTie("/radios/nav1/dme/in-range", this,
-         &FGRadioStack::get_nav1_dme_inrange);
-    fgTie("/radios/nav1/heading-needle-deflection", this,
+    fgTie("/radios/nav[0]/radials/actual-deg", this,
+         &FGRadioStack::get_nav1_radial);
+    fgTie("/radios/nav[0]/to-flag", this, &FGRadioStack::get_nav1_to_flag);
+    fgTie("/radios/nav[0]/from-flag", this, &FGRadioStack::get_nav1_from_flag);
+    fgTie("/radios/nav[0]/in-range", this, &FGRadioStack::get_nav1_inrange);
+    fgTie("/radios/nav[0]/heading-needle-deflection", this,
          &FGRadioStack::get_nav1_heading_needle_deflection);
-    fgTie("/radios/nav1/gs-needle-deflection", this,
+    fgTie("/radios/nav[0]/gs-needle-deflection", this,
          &FGRadioStack::get_nav1_gs_needle_deflection);
 
                                // User inputs
-    fgTie("/radios/nav2/frequencies/selected", this,
+    fgTie("/radios/nav[1]/frequencies/selected-mhz", this,
          &FGRadioStack::get_nav2_freq, &FGRadioStack::set_nav2_freq);
-    fgTie("/radios/nav2/frequencies/standby", this,
+    fgSetArchivable("/radios/nav[1]/frequencies/selected-mhz");
+    fgTie("/radios/nav[1]/frequencies/standby-mhz", this,
          &FGRadioStack::get_nav2_alt_freq, &FGRadioStack::set_nav2_alt_freq);
-    fgTie("/radios/nav2/radials/selected", this,
+    fgSetArchivable("/radios/nav[1]/frequencies/standby-mhz");
+    fgTie("/radios/nav[1]/radials/selected-deg", this,
          &FGRadioStack::get_nav2_sel_radial,
          &FGRadioStack::set_nav2_sel_radial);
-    fgTie("/radios/nav2/volume", this,
+    fgSetArchivable("/radios/nav[1]/radials/selected-deg");
+    fgTie("/radios/nav[1]/volume", this,
          &FGRadioStack::get_nav2_vol_btn,
          &FGRadioStack::set_nav2_vol_btn);
-    fgTie("/radios/nav2/ident", this,
+    fgSetArchivable("/radios/nav[1]/volume");
+    fgTie("/radios/nav[1]/ident", this,
          &FGRadioStack::get_nav2_ident_btn,
          &FGRadioStack::set_nav2_ident_btn);
+    fgSetArchivable("/radios/nav[1]/ident");
 
                                // Radio outputs
-    fgTie("/radios/nav2/radials/actual", this, &FGRadioStack::get_nav2_radial);
-    fgTie("/radios/nav2/to-flag", this, &FGRadioStack::get_nav2_to_flag);
-    fgTie("/radios/nav2/from-flag", this, &FGRadioStack::get_nav2_from_flag);
-    fgTie("/radios/nav2/in-range", this, &FGRadioStack::get_nav2_inrange);
-    fgTie("/radios/nav2/dme/distance", this, &FGRadioStack::get_nav2_dme_dist);
-    fgTie("/radios/nav2/dme/in-range", this,
-         &FGRadioStack::get_nav2_dme_inrange);
-    fgTie("/radios/nav2/heading-needle-deflection", this,
+    fgTie("/radios/nav[1]/radials/actual-deg", this,
+         &FGRadioStack::get_nav2_radial);
+    fgTie("/radios/nav[1]/to-flag", this, &FGRadioStack::get_nav2_to_flag);
+    fgTie("/radios/nav[1]/from-flag", this, &FGRadioStack::get_nav2_from_flag);
+    fgTie("/radios/nav[1]/in-range", this, &FGRadioStack::get_nav2_inrange);
+    fgTie("/radios/nav[1]/heading-needle-deflection", this,
          &FGRadioStack::get_nav2_heading_needle_deflection);
-    fgTie("/radios/nav2/gs-needle-deflection", this,
+    fgTie("/radios/nav[1]/gs-needle-deflection", this,
          &FGRadioStack::get_nav2_gs_needle_deflection);
 
                                // User inputs
-    fgTie("/radios/adf/frequencies/selected", this,
+    fgTie("/radios/dme/frequencies/selected-khz", this,
+         &FGRadioStack::get_dme_freq, &FGRadioStack::set_adf_freq);
+
+                               // Radio outputs
+    fgTie("/radios/dme/in-range", this, &FGRadioStack::get_dme_inrange);
+    fgTie("/radios/dme/distance-nm", this, &FGRadioStack::get_dme_dist);
+    fgTie("/radios/dme/speed-kt", this, &FGRadioStack::get_dme_spd);
+    fgTie("/radios/dme/ete-min", this, &FGRadioStack::get_dme_ete);
+
+                               // User inputs
+    fgTie("/radios/adf/frequencies/selected-khz", this,
          &FGRadioStack::get_adf_freq, &FGRadioStack::set_adf_freq);
-    fgTie("/radios/adf/frequencies/standby", this,
+    fgSetArchivable("/radios/adf/frequencies/selected-khz");
+    fgTie("/radios/adf/frequencies/standby-khz", this,
          &FGRadioStack::get_adf_alt_freq, &FGRadioStack::set_adf_alt_freq);
-    fgTie("/radios/adf/rotation", this,
+    fgSetArchivable("/radios/adf/frequencies/standby-khz");
+    fgTie("/radios/adf/rotation-deg", this,
          &FGRadioStack::get_adf_rotation, &FGRadioStack::set_adf_rotation);
+    fgSetArchivable("/radios/adf/rotation-deg");
     fgTie("/radios/adf/volume", this,
          &FGRadioStack::get_adf_vol_btn,
          &FGRadioStack::set_adf_vol_btn);
+    fgSetArchivable("/radios/adf/volume");
     fgTie("/radios/adf/ident", this,
          &FGRadioStack::get_adf_ident_btn,
          &FGRadioStack::set_adf_ident_btn);
+    fgSetArchivable("/radios/adf/ident");
+
+    fgTie("/radios/marker-beacon/inner", this,
+         &FGRadioStack::get_inner_blink);
+    fgTie("/radios/marker-beacon/middle", this,
+         &FGRadioStack::get_middle_blink);
+    fgTie("/radios/marker-beacon/outer", this,
+         &FGRadioStack::get_outer_blink);
 }
 
 void
 FGRadioStack::unbind ()
 {
-    fgUntie("/radios/nav1/frequencies/selected");
-    fgUntie("/radios/nav1/frequencies/standby");
-    fgUntie("/radios/nav1/radials/actual");
-    fgUntie("/radios/nav1/radials/selected");
-    fgUntie("/radios/nav1/on");
-    fgUntie("/radios/nav1/ident");
-    fgUntie("/radios/nav1/to-flag");
-    fgUntie("/radios/nav1/from-flag");
-    fgUntie("/radios/nav1/in-range");
-    fgUntie("/radios/nav1/dme/distance");
-    fgUntie("/radios/nav1/dme/in-range");
-    fgUntie("/radios/nav1/heading-needle-deflection");
-    fgUntie("/radios/nav1/gs-needle-deflection");
-
-    fgUntie("/radios/nav2/frequencies/selected");
-    fgUntie("/radios/nav2/frequencies/standby");
-    fgUntie("/radios/nav2/radials/actual");
-    fgUntie("/radios/nav2/radials/selected");
-    fgUntie("/radios/nav2/on");
-    fgUntie("/radios/nav2/ident");
-    fgUntie("/radios/nav2/to-flag");
-    fgUntie("/radios/nav2/from-flag");
-    fgUntie("/radios/nav2/in-range");
-    fgUntie("/radios/nav2/dme/distance");
-    fgUntie("/radios/nav2/dme/in-range");
-    fgUntie("/radios/nav2/heading-needle-deflection");
-    fgUntie("/radios/nav2/gs-needle-deflection");
-
-    fgUntie("/radios/adf/frequencies/selected");
-    fgUntie("/radios/adf/frequencies/standby");
-    fgUntie("/radios/adf/rotation");
+    fgUntie("/radios/comm[0]/frequencies/selected-mhz");
+    fgUntie("/radios/comm[0]/frequencies/standby-mhz");
+    fgUntie("/radios/comm[0]/on");
+    fgUntie("/radios/comm[0]/ident");
+
+    fgUntie("/radios/comm[1]/frequencies/selected-mhz");
+    fgUntie("/radios/comm[1]/frequencies/standby-mhz");
+    fgUntie("/radios/comm[1]/on");
+    fgUntie("/radios/comm[1]/ident");
+
+    fgUntie("/radios/nav[0]/frequencies/selected-mhz");
+    fgUntie("/radios/nav[0]/frequencies/standby-mhz");
+    fgUntie("/radios/nav[0]/radials/actual-deg");
+    fgUntie("/radios/nav[0]/radials/selected-deg");
+    fgUntie("/radios/nav[0]/on");
+    fgUntie("/radios/nav[0]/ident");
+    fgUntie("/radios/nav[0]/to-flag");
+    fgUntie("/radios/nav[0]/from-flag");
+    fgUntie("/radios/nav[0]/in-range");
+    fgUntie("/radios/nav[0]/heading-needle-deflection");
+    fgUntie("/radios/nav[0]/gs-needle-deflection");
+
+    fgUntie("/radios/nav[1]/frequencies/selected-mhz");
+    fgUntie("/radios/nav[1]/frequencies/standby-mhz");
+    fgUntie("/radios/nav[1]/radials/actual-deg");
+    fgUntie("/radios/nav[1]/radials/selected-deg");
+    fgUntie("/radios/nav[1]/on");
+    fgUntie("/radios/nav[1]/ident");
+    fgUntie("/radios/nav[1]/to-flag");
+    fgUntie("/radios/nav[1]/from-flag");
+    fgUntie("/radios/nav[1]/in-range");
+    fgUntie("/radios/nav[1]/heading-needle-deflection");
+    fgUntie("/radios/nav[1]/gs-needle-deflection");
+
+    fgUntie("/radios/dme/frequencies/selected-khz");
+
+                               // Radio outputs
+    fgUntie("/radios/dme/in-range");
+    fgUntie("/radios/dme/distance-nm");
+    fgUntie("/radios/dme/speed-kt");
+    fgUntie("/radios/dme/ete-min");
+
+    fgUntie("/radios/adf/frequencies/selected-khz");
+    fgUntie("/radios/adf/frequencies/standby-khz");
+    fgUntie("/radios/adf/rotation-deg");
     fgUntie("/radios/adf/on");
     fgUntie("/radios/adf/ident");
+
+    fgUntie("/radios/marker-beacon/inner");
+    fgUntie("/radios/marker-beacon/middle");
+    fgUntie("/radios/marker-beacon/outer");
 }
 
 
@@ -249,8 +349,8 @@ double FGRadioStack::adjustNavRange( double stationElev, double aircraftElev,
     // to model diminishing returns at too-high altitudes.
 
     // altitude difference
-    double alt = ( aircraftElev * METER_TO_FEET - stationElev );
-    // cout << "aircraft elev = " << aircraftElev * METER_TO_FEET
+    double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
+    // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
     //      << " station elev = " << stationElev << endl;
 
     if ( nominalRange < 25.0 + SG_EPSILON ) {
@@ -277,7 +377,7 @@ double FGRadioStack::adjustILSRange( double stationElev, double aircraftElev,
     // assumptions we model the standard service volume, plus
 
     // altitude difference
-    // double alt = ( aircraftElev * METER_TO_FEET - stationElev );
+    // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
     double offset = fabs( offsetDegrees );
 
     if ( offset < 10 ) {
@@ -286,6 +386,12 @@ double FGRadioStack::adjustILSRange( double stationElev, double aircraftElev,
        return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
     } else if ( offset < 45 ) {
        return (45 - offset);
+    } else if ( offset > 170 ) {
+        return FG_ILS_DEFAULT_RANGE;
+    } else if ( offset > 145 ) {
+       return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
+    } else if ( offset > 135 ) {
+        return (offset - 135);
     } else {
        return 0;
     }
@@ -296,9 +402,12 @@ double FGRadioStack::adjustILSRange( double stationElev, double aircraftElev,
 void 
 FGRadioStack::update() 
 {
-    double lon = longitudeVal->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
-    double lat = latitudeVal->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
-    double elev = altitudeVal->getDoubleValue() * FEET_TO_METER;
+    //DCL
+    string transmission;
+
+    double lon = lon_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+    double lat = lat_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+    double elev = alt_node->getDoubleValue() * SG_FEET_TO_METER;
 
     need_update = false;
 
@@ -306,18 +415,56 @@ FGRadioStack::update()
     Point3D station;
     double az1, az2, s;
 
+    ////////////////////////////////////////////////////////////////////////
+    // Comm1.
+    ////////////////////////////////////////////////////////////////////////
+
+    static bool repeating_message_registered = false;
+    static int dcl_i = 0;   //Hack to only call the transmission now and then - should use the event scheduler
+    if ( comm1_valid ) {
+       station = Point3D( comm1_x, comm1_y, comm1_z );
+       comm1_dist = aircraft.distance3D( station );
+       if ( comm1_dist < comm1_effective_range * SG_NM_TO_METER ) {
+           comm1_inrange = true;
+           // TODO - only get the transmission and register every now and then
+           if(dcl_i == 0) {
+               transmission = atis.get_transmission();
+               current_atcdisplay->ChangeRepeatingMessage(transmission);
+           }
+           if(!repeating_message_registered) {
+               current_atcdisplay->RegisterRepeatingMessage(transmission);
+               repeating_message_registered = true;
+           }
+           dcl_i++;
+           if(dcl_i == 2000) {
+               dcl_i = 0;
+           }
+       } else {
+           comm1_inrange = false;
+           if(repeating_message_registered) {
+               current_atcdisplay->CancelRepeatingMessage();
+               repeating_message_registered = false;
+           }
+           dcl_i = 0;
+       }
+    } else {
+       comm1_inrange = false;
+       if(repeating_message_registered) {
+           current_atcdisplay->CancelRepeatingMessage();
+           repeating_message_registered = false;
+       }
+       dcl_i = 0;
+       // cout << "not picking up comm1. :-(" << endl;
+    }
+
+    ////////////////////////////////////////////////////////////////////////
+    // Nav1.
+    ////////////////////////////////////////////////////////////////////////
+
     if ( nav1_valid ) {
        station = Point3D( nav1_x, nav1_y, nav1_z );
        nav1_loc_dist = aircraft.distance3D( station );
 
-       if ( nav1_has_dme ) {
-           // staightline distance
-           station = Point3D( nav1_dme_x, nav1_dme_y, nav1_dme_z );
-           nav1_dme_dist = aircraft.distance3D( station );
-       } else {
-           nav1_dme_dist = 0.0;
-       }
-
        if ( nav1_has_gs ) {
            station = Point3D( nav1_gs_x, nav1_gs_y, nav1_gs_z );
            nav1_gs_dist = aircraft.distance3D( station );
@@ -340,19 +487,19 @@ FGRadioStack::update()
            while ( offset > 180.0 ) { offset -= 360.0; }
            // cout << "ils offset = " << offset << endl;
            nav1_effective_range = adjustILSRange(nav1_elev, elev, offset,
-                                                 nav1_loc_dist * METER_TO_NM );
+                                                 nav1_loc_dist * SG_METER_TO_NM );
        } else {
            nav1_effective_range = adjustNavRange(nav1_elev, elev, nav1_range);
        }
        // cout << "nav1 range = " << nav1_effective_range
        //      << " (" << nav1_range << ")" << endl;
 
-       if ( nav1_loc_dist < nav1_effective_range * NM_TO_METER ) {
+       if ( nav1_loc_dist < nav1_effective_range * SG_NM_TO_METER ) {
            nav1_inrange = true;
-       } else if ( nav1_loc_dist < 2 * nav1_effective_range * NM_TO_METER ) {
+       } else if ( nav1_loc_dist < 2 * nav1_effective_range * SG_NM_TO_METER ) {
            nav1_inrange = sg_random() < 
-               ( 2 * nav1_effective_range * NM_TO_METER - nav1_loc_dist ) /
-               (nav1_effective_range * NM_TO_METER);
+               ( 2 * nav1_effective_range * SG_NM_TO_METER - nav1_loc_dist ) /
+               (nav1_effective_range * SG_NM_TO_METER);
        } else {
            nav1_inrange = false;
        }
@@ -362,10 +509,10 @@ FGRadioStack::update()
        }
     } else {
        nav1_inrange = false;
-       nav1_dme_dist = 0.0;
        // cout << "not picking up vor. :-(" << endl;
     }
 
+#ifdef ENABLE_AUDIO_SUPPORT
     if ( nav1_valid && nav1_inrange ) {
        // play station ident via audio system if on + ident,
        // otherwise turn it off
@@ -399,19 +546,17 @@ FGRadioStack::update()
            globals->get_soundmgr()->stop( "nav1-dme-ident" );
        }
     }
+#endif
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // Nav2.
+    ////////////////////////////////////////////////////////////////////////
 
     if ( nav2_valid ) {
        station = Point3D( nav2_x, nav2_y, nav2_z );
        nav2_loc_dist = aircraft.distance3D( station );
 
-       if ( nav2_has_dme ) {
-           // staightline distance
-           station = Point3D( nav2_dme_x, nav2_dme_y, nav2_dme_z );
-           nav2_dme_dist = aircraft.distance3D( station );
-       } else {
-           nav2_dme_dist = 0.0;
-       }
-
        if ( nav2_has_gs ) {
            station = Point3D( nav2_gs_x, nav2_gs_y, nav2_gs_z );
            nav2_gs_dist = aircraft.distance3D( station );
@@ -433,19 +578,19 @@ FGRadioStack::update()
            while ( offset > 180.0 ) { offset -= 360.0; }
            // cout << "ils offset = " << offset << endl;
            nav2_effective_range = adjustILSRange(nav2_elev, elev, offset,
-                                                 nav2_loc_dist * METER_TO_NM );
+                                                 nav2_loc_dist * SG_METER_TO_NM );
        } else {
            nav2_effective_range = adjustNavRange(nav2_elev, elev, nav2_range);
        }
        // cout << "nav2 range = " << nav2_effective_range
        //      << " (" << nav2_range << ")" << endl;
 
-       if ( nav2_loc_dist < nav2_effective_range * NM_TO_METER ) {
+       if ( nav2_loc_dist < nav2_effective_range * SG_NM_TO_METER ) {
            nav2_inrange = true;
-       } else if ( nav2_loc_dist < 2 * nav2_effective_range * NM_TO_METER ) {
+       } else if ( nav2_loc_dist < 2 * nav2_effective_range * SG_NM_TO_METER ) {
            nav2_inrange = sg_random() < 
-               ( 2 * nav2_effective_range * NM_TO_METER - nav2_loc_dist ) /
-               (nav2_effective_range * NM_TO_METER);
+               ( 2 * nav2_effective_range * SG_NM_TO_METER - nav2_loc_dist ) /
+               (nav2_effective_range * SG_NM_TO_METER);
        } else {
            nav2_inrange = false;
        }
@@ -455,10 +600,10 @@ FGRadioStack::update()
        }
     } else {
        nav2_inrange = false;
-       nav2_dme_dist = 0.0;
        // cout << "not picking up vor. :-(" << endl;
     }
 
+#ifdef ENABLE_AUDIO_SUPPORT
     if ( nav2_valid && nav2_inrange ) {
        // play station ident via audio system if on + ident,
        // otherwise turn it off
@@ -492,8 +637,60 @@ FGRadioStack::update()
            globals->get_soundmgr()->stop( "nav2-dme-ident" );
        }
     }
+#endif
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // DME.
+    ////////////////////////////////////////////////////////////////////////
+
+    if (dme_valid) {
+       station = Point3D( dme_x, dme_y, dme_z );
+       dme_dist = aircraft.distance3D( station ) * SG_METER_TO_NM;
+       dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
+       if (dme_dist < dme_effective_range * SG_NM_TO_METER) {
+         dme_inrange = true;
+       } else if (dme_dist < 2 * dme_effective_range * SG_NM_TO_METER) {
+         dme_inrange = sg_random() <
+           (2 * dme_effective_range * SG_NM_TO_METER - dme_dist) /
+           (dme_effective_range * SG_NM_TO_METER);
+       } else {
+         dme_inrange = false;
+       }
+       if (dme_inrange) {
+         SGTimeStamp current_time;
+         station = Point3D( dme_x, dme_y, dme_z );
+         dme_dist = aircraft.distance3D( station ) * SG_METER_TO_NM;
+         current_time.stamp();
+         long dMs = (current_time - dme_last_time) / 1000;
+                               // Update every second
+         if (dMs >= 1000) {
+           double dDist = dme_dist - dme_prev_dist;
+           dme_spd = fabs((dDist/dMs) * 3600000);
+                               // FIXME: the panel should be able to
+                               // handle this!!!
+           if (dme_spd > 999.0)
+             dme_spd = 999.0;
+           dme_ete = fabs((dme_dist/dme_spd) * 60.0);
+                               // FIXME: the panel should be able to
+                               // handle this!!!
+           if (dme_ete > 99.0)
+             dme_ete = 99.0;
+           dme_prev_dist = dme_dist;
+           dme_last_time.stamp();
+         }
+       }
+    } else {
+      dme_inrange = false;
+      dme_dist = 0.0;
+      dme_prev_dist = 0.0;
+    }
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // ADF
+    ////////////////////////////////////////////////////////////////////////
 
-    // adf
     if ( adf_valid ) {
        // staightline distance
        station = Point3D( adf_x, adf_y, adf_z );
@@ -508,12 +705,12 @@ FGRadioStack::update()
        //      << " dist = " << nav2_dist << endl;
 
        adf_effective_range = kludgeRange(adf_elev, elev, adf_range);
-       if ( adf_dist < adf_effective_range * NM_TO_METER ) {
+       if ( adf_dist < adf_effective_range * SG_NM_TO_METER ) {
            adf_inrange = true;
-       } else if ( adf_dist < 2 * adf_effective_range * NM_TO_METER ) {
+       } else if ( adf_dist < 2 * adf_effective_range * SG_NM_TO_METER ) {
            adf_inrange = sg_random() < 
-               ( 2 * adf_effective_range * NM_TO_METER - adf_dist ) /
-               (adf_effective_range * NM_TO_METER);
+               ( 2 * adf_effective_range * SG_NM_TO_METER - adf_dist ) /
+               (adf_effective_range * SG_NM_TO_METER);
        } else {
            adf_inrange = false;
        }
@@ -521,6 +718,7 @@ FGRadioStack::update()
        adf_inrange = false;
     }
 
+#ifdef ENABLE_AUDIO_SUPPORT
     if ( adf_valid && adf_inrange ) {
        // play station ident via audio system if on + ident,
        // otherwise turn it off
@@ -544,25 +742,115 @@ FGRadioStack::update()
            globals->get_soundmgr()->stop( "adf-ident" );
        }
     }
+#endif
+
+    // marker beacon blinking
+    bool light_on = ( outer_blink || middle_blink || inner_blink );
+    SGTimeStamp current;
+    current.stamp();
+
+    if ( light_on && (current - blink > 400000) ) {
+       light_on = false;
+       blink.stamp();
+    } else if ( !light_on && (current - blink > 100000) ) {
+       light_on = true;
+       blink.stamp();
+    }
+
+    if ( outer_marker ) {
+       outer_blink = light_on;
+    } else {
+       outer_blink = false;
+    }
+
+    if ( middle_marker ) {
+       middle_blink = light_on;
+    } else {
+       middle_blink = false;
+    }
+
+    if ( inner_marker ) {
+       inner_blink = light_on;
+    } else {
+       inner_blink = false;
+    }
+
+    // cout << outer_blink << " " << middle_blink << " " << inner_blink << endl;
 }
 
 
 // Update current nav/adf radio stations based on current postition
 void FGRadioStack::search() 
 {
-    double lon = longitudeVal->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
-    double lat = latitudeVal->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
-    double elev = altitudeVal->getDoubleValue() * FEET_TO_METER;
+    static FGMkrBeacon::fgMkrBeacType last_beacon = FGMkrBeacon::NOBEACON;
+
+    double lon = lon_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+    double lat = lat_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
+    double elev = alt_node->getDoubleValue() * SG_FEET_TO_METER;
+
+                               // FIXME: the panel should handle this
+                               // don't worry about overhead for now,
+                               // since this is handled only periodically
+    int dme_switch_pos = fgGetInt("/radios/dme/switch-position");
+    if (dme_switch_pos == 0) {
+      dme_freq = 0;
+      dme_inrange = false;
+    } else if (dme_switch_pos == 1) {
+      if (dme_freq != nav1_freq) {
+       dme_freq = nav1_freq;
+       need_update = true;
+      }
+    } else if (dme_switch_pos == 3) {
+      if (dme_freq != nav2_freq) {
+       dme_freq = nav2_freq;
+       need_update = true;
+      }
+    }
 
-    // nav1
     FGILS ils;
     FGNav nav;
 
+    static string last_comm1_ident = "";
+    static string last_comm2_ident = "";
     static string last_nav1_ident = "";
     static string last_nav2_ident = "";
     static string last_adf_ident = "";
     static bool last_nav1_vor = false;
     static bool last_nav2_vor = false;
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // Comm1.
+    ////////////////////////////////////////////////////////////////////////
+
+    if ( current_atislist->query( lon, lat, elev, comm1_freq, &atis ) ) {
+       //cout << "atis found in radiostack search !!!!" << endl;
+       comm1_ident = atis.get_ident();
+       comm1_valid = true;
+       if ( last_comm1_ident != comm1_ident ) {
+           //nav1_trans_ident = ils.get_trans_ident();
+           last_comm1_ident = comm1_ident;
+           comm1_elev = atis.get_elev();
+           comm1_range = FG_ATIS_DEFAULT_RANGE;
+           comm1_effective_range = comm1_range;
+           comm1_x = atis.get_x();
+           comm1_y = atis.get_y();
+           comm1_z = atis.get_z();
+           //cout << "Found a new atis station in range" << endl;
+           //cout << " id = " << atis.get_ident() << endl;
+       }
+    } else {
+       comm1_valid = false;
+       comm1_ident = "";
+       //comm1_trans_ident = "";
+       last_comm1_ident = "";
+       // cout << "not picking up atis" << endl;
+    }
+
+    ////////////////////////////////////////////////////////////////////////
+    // Nav1.
+    ////////////////////////////////////////////////////////////////////////
+
     if ( current_ilslist->query( lon, lat, elev, nav1_freq, &ils ) ) {
        nav1_ident = ils.get_locident();
        nav1_valid = true;
@@ -578,8 +866,6 @@ void FGRadioStack::search()
            nav1_loclat = ils.get_loclat();
            nav1_gslon = ils.get_gslon();
            nav1_gslat = ils.get_gslat();
-           nav1_dmelon = ils.get_dmelon();
-           nav1_dmelat = ils.get_dmelat();
            nav1_elev = ils.get_gselev();
            nav1_magvar = 0;
            nav1_range = FG_ILS_DEFAULT_RANGE;
@@ -594,10 +880,8 @@ void FGRadioStack::search()
            nav1_gs_x = ils.get_gs_x();
            nav1_gs_y = ils.get_gs_y();
            nav1_gs_z = ils.get_gs_z();
-           nav1_dme_x = ils.get_dme_x();
-           nav1_dme_y = ils.get_dme_y();
-           nav1_dme_z = ils.get_dme_z();
 
+#ifdef ENABLE_AUDIO_SUPPORT
            if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
                globals->get_soundmgr()->remove( "nav1-vor-ident" );
            }
@@ -622,6 +906,7 @@ void FGRadioStack::search()
            //      << " nav1_last_time = " << nav1_last_time
            //      << " current time = "
            //      << globals->get_time_params()->get_cur_time() << endl;
+#endif
 
            // cout << "Found an ils station in range" << endl;
            // cout << " id = " << ils.get_locident() << endl;
@@ -644,10 +929,11 @@ void FGRadioStack::search()
            nav1_effective_range = adjustNavRange(nav1_elev, elev, nav1_range);
            nav1_target_gs = 0.0;
            nav1_radial = nav1_sel_radial;
-           nav1_x = nav1_dme_x = nav.get_x();
-           nav1_y = nav1_dme_y = nav.get_y();
-           nav1_z = nav1_dme_z = nav.get_z();
+           nav1_x = nav.get_x();
+           nav1_y = nav.get_y();
+           nav1_z = nav.get_z();
 
+#ifdef ENABLE_AUDIO_SUPPORT
            if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
                globals->get_soundmgr()->remove( "nav1-vor-ident" );
            }
@@ -671,6 +957,7 @@ void FGRadioStack::search()
            //      << nav1_play_count << " nav1_last_time = "
            //      << nav1_last_time << " current time = "
            //      << globals->get_time_params()->get_cur_time() << endl;
+#endif
 
            // cout << "Found a vor station in range" << endl;
            // cout << " id = " << nav.get_ident() << endl;
@@ -679,14 +966,20 @@ void FGRadioStack::search()
        nav1_valid = false;
        nav1_ident = "";
        nav1_radial = 0;
-       nav1_dme_dist = 0;
        nav1_trans_ident = "";
        last_nav1_ident = "";
+#ifdef ENABLE_AUDIO_SUPPORT
        globals->get_soundmgr()->remove( "nav1-vor-ident" );
        globals->get_soundmgr()->remove( "nav1-dme-ident" );
+#endif
        // cout << "not picking up vor1. :-(" << endl;
     }
 
+
+    ////////////////////////////////////////////////////////////////////////
+    // Nav2.
+    ////////////////////////////////////////////////////////////////////////
+
     if ( current_ilslist->query( lon, lat, elev, nav2_freq, &ils ) ) {
        nav2_ident = ils.get_locident();
        nav2_valid = true;
@@ -714,10 +1007,8 @@ void FGRadioStack::search()
            nav2_gs_x = ils.get_gs_x();
            nav2_gs_y = ils.get_gs_y();
            nav2_gs_z = ils.get_gs_z();
-           nav2_dme_x = ils.get_dme_x();
-           nav2_dme_y = ils.get_dme_y();
-           nav2_dme_z = ils.get_dme_z();
 
+#ifdef ENABLE_AUDIO_SUPPORT
            if ( globals->get_soundmgr()->exists( "nav2-vor-ident" ) ) {
                globals->get_soundmgr()->remove( "nav2-vor-ident" );
            }
@@ -741,6 +1032,7 @@ void FGRadioStack::search()
            //      << nav2_play_count << " nav2_last_time = "
            //      << nav2_last_time << " current time = "
            //      << globals->get_time_params()->get_cur_time() << endl;
+#endif
 
            // cout << "Found an ils station in range" << endl;
            // cout << " id = " << ils.get_locident() << endl;
@@ -763,10 +1055,11 @@ void FGRadioStack::search()
            nav2_effective_range = adjustNavRange(nav2_elev, elev, nav2_range);
            nav2_target_gs = 0.0;
            nav2_radial = nav2_sel_radial;
-           nav2_x = nav2_dme_x = nav.get_x();
-           nav2_y = nav2_dme_y = nav.get_y();
-           nav2_z = nav2_dme_z = nav.get_z();
+           nav2_x = nav.get_x();
+           nav2_y = nav.get_y();
+           nav2_z = nav.get_z();
 
+#ifdef ENABLE_AUDIO_SUPPORT
            if ( globals->get_soundmgr()->exists( "nav2-vor-ident" ) ) {
                globals->get_soundmgr()->remove( "nav2-vor-ident" );
            }
@@ -790,6 +1083,7 @@ void FGRadioStack::search()
            //      << nav2_play_count << " nav2_last_time = "
            //      << nav2_last_time << " current time = "
            //      << globals->get_time_params()->get_cur_time() << endl;
+#endif
 
            // cout << "Found a vor station in range" << endl;
            // cout << " id = " << nav.get_ident() << endl;
@@ -798,34 +1092,123 @@ void FGRadioStack::search()
        nav2_valid = false;
        nav2_ident = "";
        nav2_radial = 0;
-       nav2_dme_dist = 0;
        nav2_trans_ident = "";
        last_nav2_ident = "";
+#ifdef ENABLE_AUDIO_SUPPORT
        globals->get_soundmgr()->remove( "nav2-vor-ident" );
        globals->get_soundmgr()->remove( "nav2-dme-ident" );
+#endif
        // cout << "not picking up vor1. :-(" << endl;
     }
 
-    FGBeacon::fgMkrBeacType beacon_type
-       = current_beacons->query( lon * SGD_RADIANS_TO_DEGREES, lat * SGD_RADIANS_TO_DEGREES, elev );
+
+    ////////////////////////////////////////////////////////////////////////
+    // DME
+    ////////////////////////////////////////////////////////////////////////
+
+    if ( current_ilslist->query( lon, lat, elev, dme_freq, &ils ) ) {
+      if (ils.get_has_dme()) {
+       dme_valid = true;
+       dme_lon = ils.get_loclon();
+       dme_lat = ils.get_loclat();
+       dme_elev = ils.get_gselev();
+       dme_range = FG_ILS_DEFAULT_RANGE;
+       dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
+       dme_x = ils.get_dme_x();
+       dme_y = ils.get_dme_y();
+       dme_z = ils.get_dme_z();
+      }
+    } else if ( current_navlist->query( lon, lat, elev, dme_freq, &nav ) ) {
+      if (nav.get_has_dme()) {
+       dme_valid = true;
+       dme_lon = nav.get_lon();
+       dme_lat = nav.get_lat();
+       dme_elev = nav.get_elev();
+       dme_range = nav.get_range();
+       dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
+       dme_x = nav.get_x();
+       dme_y = nav.get_y();
+       dme_z = nav.get_z();
+      }
+    } else {
+      dme_valid = false;
+      dme_dist = 0;
+    }
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // Beacons.
+    ////////////////////////////////////////////////////////////////////////
+
+    FGMkrBeacon::fgMkrBeacType beacon_type
+       = current_beacons->query( lon * SGD_RADIANS_TO_DEGREES,
+                                 lat * SGD_RADIANS_TO_DEGREES, elev );
 
     outer_marker = middle_marker = inner_marker = false;
 
-    if ( beacon_type == FGBeacon::OUTER ) {
+    if ( beacon_type == FGMkrBeacon::OUTER ) {
        outer_marker = true;
-       cout << "OUTER MARKER" << endl;
-    } else if ( beacon_type == FGBeacon::MIDDLE ) {
+       // cout << "OUTER MARKER" << endl;
+#ifdef ENABLE_AUDIO_SUPPORT
+       if ( last_beacon != FGMkrBeacon::OUTER ) {
+           if ( ! globals->get_soundmgr()->exists( "outer-marker" ) ) {
+               FGSimpleSound *sound = beacon.get_outer();
+               sound->set_volume( 0.3 );
+               globals->get_soundmgr()->add( sound, "outer-marker" );
+           }
+           if ( !globals->get_soundmgr()->is_playing("outer-marker") ) {
+               globals->get_soundmgr()->play_looped( "outer-marker" );
+           }
+       }
+#endif
+    } else if ( beacon_type == FGMkrBeacon::MIDDLE ) {
        middle_marker = true;
-       cout << "MIDDLE MARKER" << endl;
-    } else if ( beacon_type == FGBeacon::INNER ) {
+       // cout << "MIDDLE MARKER" << endl;
+#ifdef ENABLE_AUDIO_SUPPORT
+       if ( last_beacon != FGMkrBeacon::MIDDLE ) {
+           if ( ! globals->get_soundmgr()->exists( "middle-marker" ) ) {
+               FGSimpleSound *sound = beacon.get_middle();
+               sound->set_volume( 0.3 );
+               globals->get_soundmgr()->add( sound, "middle-marker" );
+           }
+           if ( !globals->get_soundmgr()->is_playing("middle-marker") ) {
+               globals->get_soundmgr()->play_looped( "middle-marker" );
+           }
+       }
+#endif
+    } else if ( beacon_type == FGMkrBeacon::INNER ) {
        inner_marker = true;
-       cout << "INNER MARKER" << endl;
+       // cout << "INNER MARKER" << endl;
+#ifdef ENABLE_AUDIO_SUPPORT
+       if ( last_beacon != FGMkrBeacon::INNER ) {
+           if ( ! globals->get_soundmgr()->exists( "inner-marker" ) ) {
+               FGSimpleSound *sound = beacon.get_inner();
+               sound->set_volume( 0.3 );
+               globals->get_soundmgr()->add( sound, "inner-marker" );
+           }
+           if ( !globals->get_soundmgr()->is_playing("inner-marker") ) {
+               globals->get_soundmgr()->play_looped( "inner-marker" );
+           }
+       }
+#endif
+    } else {
+       // cout << "no marker" << endl;
+#ifdef ENABLE_AUDIO_SUPPORT
+       globals->get_soundmgr()->stop( "outer-marker" );
+       globals->get_soundmgr()->stop( "middle-marker" );
+       globals->get_soundmgr()->stop( "inner-marker" );
+#endif
     }
+    last_beacon = beacon_type;
+
+
+    ////////////////////////////////////////////////////////////////////////
+    // ADF.
+    ////////////////////////////////////////////////////////////////////////
 
-    // adf
     if ( current_navlist->query( lon, lat, elev, adf_freq, &nav ) ) {
        char freq[128];
-#if defined( _MSC_VER )
+#if defined( _MSC_VER ) || defined(__MINGW32__)
        _snprintf( freq, 10, "%.0f", adf_freq );
 #else
        snprintf( freq, 10, "%.0f", adf_freq );
@@ -847,6 +1230,7 @@ void FGRadioStack::search()
            adf_y = nav.get_y();
            adf_z = nav.get_z();
 
+#ifdef ENABLE_AUDIO_SUPPORT
            if ( globals->get_soundmgr()->exists( "adf-ident" ) ) {
                globals->get_soundmgr()->remove( "adf-ident" );
            }
@@ -863,6 +1247,7 @@ void FGRadioStack::search()
            //      << adf_play_count << " adf_last_time = "
            //      << adf_last_time << " current time = "
            //      << globals->get_time_params()->get_cur_time() << endl;
+#endif
 
            // cout << "Found an adf station in range" << endl;
            // cout << " id = " << nav.get_ident() << endl;
@@ -871,7 +1256,9 @@ void FGRadioStack::search()
        adf_valid = false;
        adf_ident = "";
        adf_trans_ident = "";
+#ifdef ENABLE_AUDIO_SUPPORT
        globals->get_soundmgr()->remove( "adf-ident" );
+#endif
        last_adf_ident = "";
        // cout << "not picking up adf. :-(" << endl;
     }
@@ -938,7 +1325,8 @@ double FGRadioStack::get_nav2_heading_needle_deflection() const {
 double FGRadioStack::get_nav1_gs_needle_deflection() const {
     if ( nav1_inrange && nav1_has_gs ) {
        double x = nav1_gs_dist;
-       double y = (FGBFI::getAltitude() - nav1_elev) * FEET_TO_METER;
+       double y = (fgGetDouble("/position/altitude-ft") - nav1_elev)
+            * SG_FEET_TO_METER;
        double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
        return (nav1_target_gs - angle) * 5.0;
     } else {
@@ -952,7 +1340,8 @@ double FGRadioStack::get_nav1_gs_needle_deflection() const {
 double FGRadioStack::get_nav2_gs_needle_deflection() const {
     if ( nav2_inrange && nav2_has_gs ) {
        double x = nav2_gs_dist;
-       double y = (FGBFI::getAltitude() - nav2_elev) * FEET_TO_METER;
+       double y = (fgGetDouble("/position/altitude-ft") - nav2_elev)
+            * SG_FEET_TO_METER;
        double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
        return (nav2_target_gs - angle) * 5.0;
     } else {