1 // radiostack.cxx -- class to manage an instance of the radio stack
3 // Written by Curtis Olson, started April 2000.
5 // Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #include <simgear/math/sg_random.h>
26 #include <Aircraft/aircraft.hxx>
27 #include <Main/bfi.hxx>
28 #include <Navaids/ilslist.hxx>
29 #include <Navaids/navlist.hxx>
30 #include <Time/event.hxx>
32 #include "radiostack.hxx"
34 static int nav1_play_count = 0;
35 static time_t nav1_last_time = 0;
38 FGRadioStack *current_radiostack;
42 * Boy, this is ugly! Make the VOR range vary by altitude difference.
44 static double kludgeRange ( double stationElev, double aircraftElev,
47 // Assume that the nominal range (usually
48 // 50nm) applies at a 5,000 ft difference.
50 double factor = ((aircraftElev*METER_TO_FEET) - stationElev) / 5000.0;
51 double range = fabs(nominalRange * factor);
53 // Clamp the range to keep it sane; for
54 // now, never less than 25% or more than
55 // 500% of nominal range.
56 if (range < nominalRange/4.0) {
57 range = nominalRange/4.0;
58 } else if (range > nominalRange*5.0) {
59 range = nominalRange*5.0;
66 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
67 static double adjustNavRange( double stationElev, double aircraftElev,
70 // assumptions we model the standard service volume, plus
71 // ... rather than specifying a cylinder, we model a cone that
72 // contains the cylinder. Then we put an upside down cone on top
73 // to model diminishing returns at too-high altitudes.
75 // altitude difference
76 double alt = ( aircraftElev - stationElev ) * METER_TO_FEET;
78 if ( nominalRange < 25.0 + FG_EPSILON ) {
79 // Standard Terminal Service Volume
80 if ( alt <= 1000.0 ) {
82 } else if ( alt <= 12000.0 ) {
83 return nominalRange + nominalRange * ( alt - 1000.0 ) / 11000.0;
84 } else if ( alt <= 18000.0 ) {
85 return nominalRange * 2 * ( 1 - ( alt - 12000.0 ) / 6000.0 );
89 } else if ( nominalRange < 50.0 + FG_EPSILON ) {
90 // Standard Low Altitude Service Volume
91 if ( alt <= 1000.0 ) {
93 } else if ( alt <= 18000.0 ) {
94 return nominalRange + nominalRange * ( alt - 1000.0 ) / 17000.0;
95 } else if ( alt <= 18000.0 ) {
96 return nominalRange * 2 * ( 1 - ( alt - 18000.0 ) / 9000.0 );
101 // Standard High Altitude Service Volume
102 double lc = nominalRange * 0.31;
103 double mc = nominalRange * 0.77;
104 double hc = nominalRange;
106 if ( alt <= 1000.0 ) {
108 } else if ( alt <= 14500.0 ) {
109 return lc + (mc-lc) * ( alt - 1000.0 ) / 13500.0;
110 } else if ( alt <= 18000.0 ) {
111 return mc + (hc-mc) * ( alt - 14500.0 ) / 3500.0;
112 } else if ( alt <= 45000.0 ) {
113 return hc + hc * ( 1 - fabs(alt - 31500.0) / 13500.0 );
114 } else if ( alt <= 60000.0 ) {
115 return mc + (hc-mc) * (60000.0 - alt) / 15000.0;
116 } else if ( alt <= 75000.0 ) {
117 return mc * ( 75000.0 - alt ) / 15000.0;
125 // periodic radio station search wrapper
126 static void fgRadioSearch( void ) {
127 current_radiostack->search();
131 FGRadioStack::FGRadioStack() {
137 longitudeVal = fgGetValue("/position/longitude");
138 latitudeVal = fgGetValue("/position/latitude");
139 altitudeVal = fgGetValue("/position/altitude");
144 FGRadioStack::~FGRadioStack()
146 unbind(); // FIXME: should be called externally
151 FGRadioStack::init ()
158 // Search radio database once per second
159 global_events.Register( "fgRadioSearch()", fgRadioSearch,
160 fgEVENT::FG_EVENT_READY, 1000);
164 FGRadioStack::bind ()
167 fgTie("/radios/nav1/frequencies/selected", this,
168 &FGRadioStack::get_nav1_freq, &FGRadioStack::set_nav1_freq);
169 fgTie("/radios/nav1/frequencies/standby", this,
170 &FGRadioStack::get_nav1_alt_freq, &FGRadioStack::set_nav1_alt_freq);
171 fgTie("/radios/nav1/radials/selected", this,
172 &FGRadioStack::get_nav1_sel_radial,
173 &FGRadioStack::set_nav1_sel_radial);
174 fgTie("/radios/nav1/on", this,
175 &FGRadioStack::get_nav1_on_btn,
176 &FGRadioStack::set_nav1_on_btn);
177 fgTie("/radios/nav1/ident", this,
178 &FGRadioStack::get_nav1_ident_btn,
179 &FGRadioStack::set_nav1_ident_btn);
182 fgTie("/radios/nav1/radials/actual", this, &FGRadioStack::get_nav1_radial);
183 fgTie("/radios/nav1/to-flag", this, &FGRadioStack::get_nav1_to_flag);
184 fgTie("/radios/nav1/from-flag", this, &FGRadioStack::get_nav1_from_flag);
185 fgTie("/radios/nav1/in-range", this, &FGRadioStack::get_nav1_inrange);
186 fgTie("/radios/nav1/dme/distance", this, &FGRadioStack::get_nav1_dme_dist);
187 fgTie("/radios/nav1/dme/in-range", this,
188 &FGRadioStack::get_nav1_dme_inrange);
189 fgTie("/radios/nav1/heading-needle-deflection", this,
190 &FGRadioStack::get_nav1_heading_needle_deflection);
191 fgTie("/radios/nav1/gs-needle-deflection", this,
192 &FGRadioStack::get_nav1_gs_needle_deflection);
195 fgTie("/radios/nav2/frequencies/selected", this,
196 &FGRadioStack::get_nav2_freq, &FGRadioStack::set_nav2_freq);
197 fgTie("/radios/nav2/frequencies/standby", this,
198 &FGRadioStack::get_nav2_alt_freq, &FGRadioStack::set_nav2_alt_freq);
199 fgTie("/radios/nav2/radials/selected", this,
200 &FGRadioStack::get_nav2_sel_radial,
201 &FGRadioStack::set_nav2_sel_radial);
202 fgTie("/radios/nav2/on", this,
203 &FGRadioStack::get_nav2_on_btn,
204 &FGRadioStack::set_nav2_on_btn);
205 fgTie("/radios/nav2/ident", this,
206 &FGRadioStack::get_nav2_ident_btn,
207 &FGRadioStack::set_nav2_ident_btn);
210 fgTie("/radios/nav2/radials/actual", this, &FGRadioStack::get_nav2_radial);
211 fgTie("/radios/nav2/to-flag", this, &FGRadioStack::get_nav2_to_flag);
212 fgTie("/radios/nav2/from-flag", this, &FGRadioStack::get_nav2_from_flag);
213 fgTie("/radios/nav2/in-range", this, &FGRadioStack::get_nav2_inrange);
214 fgTie("/radios/nav2/dme/distance", this, &FGRadioStack::get_nav2_dme_dist);
215 fgTie("/radios/nav2/dme/in-range", this,
216 &FGRadioStack::get_nav2_dme_inrange);
217 fgTie("/radios/nav2/heading-needle-deflection", this,
218 &FGRadioStack::get_nav2_heading_needle_deflection);
219 fgTie("/radios/nav2/gs-needle-deflection", this,
220 &FGRadioStack::get_nav2_gs_needle_deflection);
223 fgTie("/radios/adf/frequencies/selected", this,
224 &FGRadioStack::get_adf_freq, &FGRadioStack::set_adf_freq);
225 fgTie("/radios/adf/frequencies/standby", this,
226 &FGRadioStack::get_adf_alt_freq, &FGRadioStack::set_adf_alt_freq);
227 fgTie("/radios/adf/rotation", this,
228 &FGRadioStack::get_adf_rotation, &FGRadioStack::set_adf_rotation);
232 FGRadioStack::unbind ()
234 fgUntie("/radios/nav1/frequencies/selected");
235 fgUntie("/radios/nav1/frequencies/standby");
236 fgUntie("/radios/nav1/radials/actual");
237 fgUntie("/radios/nav1/radials/selected");
238 fgUntie("/radios/nav1/on");
239 fgUntie("/radios/nav1/ident");
240 fgUntie("/radios/nav1/to-flag");
241 fgUntie("/radios/nav1/from-flag");
242 fgUntie("/radios/nav1/in-range");
243 fgUntie("/radios/nav1/dme/distance");
244 fgUntie("/radios/nav1/dme/in-range");
245 fgUntie("/radios/nav1/heading-needle-deflection");
246 fgUntie("/radios/nav1/gs-needle-deflection");
248 fgUntie("/radios/nav2/frequencies/selected");
249 fgUntie("/radios/nav2/frequencies/standby");
250 fgUntie("/radios/nav2/radials/actual");
251 fgUntie("/radios/nav2/radials/selected");
252 fgUntie("/radios/nav2/on");
253 fgUntie("/radios/nav2/ident");
254 fgUntie("/radios/nav2/to-flag");
255 fgUntie("/radios/nav2/from-flag");
256 fgUntie("/radios/nav2/in-range");
257 fgUntie("/radios/nav2/dme/distance");
258 fgUntie("/radios/nav2/dme/in-range");
259 fgUntie("/radios/nav2/heading-needle-deflection");
260 fgUntie("/radios/nav2/gs-needle-deflection");
262 fgUntie("/radios/adf/frequencies/selected");
263 fgUntie("/radios/adf/frequencies/standby");
264 fgUntie("/radios/adf/rotation");
267 // Update the various nav values based on position and valid tuned in navs
269 FGRadioStack::update()
271 double lon = longitudeVal->getDoubleValue() * DEG_TO_RAD;
272 double lat = latitudeVal->getDoubleValue() * DEG_TO_RAD;
273 double elev = altitudeVal->getDoubleValue() * FEET_TO_METER;
277 Point3D aircraft = sgGeodToCart( Point3D( lon, lat, elev ) );
282 station = Point3D( nav1_x, nav1_y, nav1_z );
283 nav1_loc_dist = aircraft.distance3D( station );
285 if ( nav1_has_dme ) {
286 // staightline distance
287 station = Point3D( nav1_dme_x, nav1_dme_y, nav1_dme_z );
288 nav1_dme_dist = aircraft.distance3D( station );
294 station = Point3D( nav1_gs_x, nav1_gs_y, nav1_gs_z );
295 nav1_gs_dist = aircraft.distance3D( station );
300 nav1_effective_range = kludgeRange(nav1_elev, elev, nav1_range);
301 if ( nav1_loc_dist < nav1_effective_range * NM_TO_METER ) {
305 geo_inverse_wgs_84( elev, lat * RAD_TO_DEG, lon * RAD_TO_DEG,
306 nav1_loclat, nav1_loclon,
308 // cout << "az1 = " << az1 << " magvar = " << nav1_magvar << endl;
309 nav1_heading = az1 - nav1_magvar;
310 // Alex: nav1_heading = - (az1 - FGBFI::getMagVar() / RAD_TO_DEG);
312 // cout << " heading = " << nav1_heading
313 // << " dist = " << nav1_dist << endl;
315 nav1_inrange = false;
320 nav1_radial = nav1_sel_radial;
323 nav1_inrange = false;
325 // cout << "not picking up vor. :-(" << endl;
328 if ( nav1_valid && nav1_inrange ) {
329 // play station ident via audio system if on + ident,
330 // otherwise turn it off
331 if ( nav1_on_btn && nav1_ident_btn ) {
332 if ( nav1_last_time <
333 globals->get_time_params()->get_cur_time() - 30 ) {
334 nav1_last_time = globals->get_time_params()->get_cur_time();
337 if ( nav1_play_count < 4 ) {
339 if ( !globals->get_soundmgr()->is_playing("nav1-vor-ident") ) {
340 globals->get_soundmgr()->play_once( "nav1-vor-ident" );
343 } else if ( nav1_play_count < 5 && nav1_has_dme ) {
345 if ( !globals->get_soundmgr()->is_playing("nav1-vor-ident") &&
346 !globals->get_soundmgr()->is_playing("nav1-dme-ident") ) {
347 globals->get_soundmgr()->play_once( "nav1-dme-ident" );
352 globals->get_soundmgr()->stop( "nav1-vor-ident" );
353 globals->get_soundmgr()->stop( "nav1-dme-ident" );
358 station = Point3D( nav2_x, nav2_y, nav2_z );
359 nav2_loc_dist = aircraft.distance3D( station );
361 if ( nav2_has_dme ) {
362 // staightline distance
363 station = Point3D( nav2_dme_x, nav2_dme_y, nav2_dme_z );
364 nav2_dme_dist = aircraft.distance3D( station );
370 station = Point3D( nav2_gs_x, nav2_gs_y, nav2_gs_z );
371 nav2_gs_dist = aircraft.distance3D( station );
376 nav2_effective_range = kludgeRange(nav2_elev, elev, nav2_range);
377 if ( nav2_loc_dist < nav2_effective_range * NM_TO_METER ) {
381 geo_inverse_wgs_84( elev, lat * RAD_TO_DEG, lon * RAD_TO_DEG,
382 nav2_loclat, nav2_loclon,
384 nav2_heading = az1 - nav2_magvar;
385 // Alex: nav2_heading = - (az1 - FGBFI::getMagVar() / RAD_TO_DEG);
387 // cout << " heading = " << nav2_heading
388 // << " dist = " << nav2_dist << endl;
390 nav2_inrange = false;
394 nav2_radial = nav2_sel_radial;
397 nav2_inrange = false;
398 // cout << "not picking up vor. :-(" << endl;
403 // staightline distance
404 station = Point3D( adf_x, adf_y, adf_z );
405 adf_dist = aircraft.distance3D( station );
407 adf_effective_range = kludgeRange(adf_elev, elev, adf_range);
408 if ( adf_dist < adf_effective_range * NM_TO_METER ) {
412 geo_inverse_wgs_84( elev, lat * RAD_TO_DEG, lon * RAD_TO_DEG,
417 // cout << " heading = " << nav2_heading
418 // << " dist = " << nav2_dist << endl;
428 // Update current nav/adf radio stations based on current postition
429 void FGRadioStack::search()
431 double lon = longitudeVal->getDoubleValue() * DEG_TO_RAD;
432 double lat = latitudeVal->getDoubleValue() * DEG_TO_RAD;
433 double elev = altitudeVal->getDoubleValue() * FEET_TO_METER;
439 static string last_nav1_ident = "";
440 static string last_nav2_ident = "";
441 static bool last_nav1_vor = false;
442 static bool last_nav2_vor = false;
443 if ( current_ilslist->query( lon, lat, elev, nav1_freq, &ils ) ) {
444 nav1_ident = ils.get_locident();
445 if ( last_nav1_ident != nav1_ident || last_nav1_vor ) {
446 nav1_trans_ident = ils.get_trans_ident();
447 last_nav1_ident = nav1_ident;
448 last_nav1_vor = false;
451 nav1_has_dme = ils.get_has_dme();
452 nav1_has_gs = ils.get_has_gs();
454 nav1_loclon = ils.get_loclon();
455 nav1_loclat = ils.get_loclat();
456 nav1_gslon = ils.get_gslon();
457 nav1_gslat = ils.get_gslat();
458 nav1_dmelon = ils.get_dmelon();
459 nav1_dmelat = ils.get_dmelat();
460 nav1_elev = ils.get_gselev();
462 nav1_range = FG_ILS_DEFAULT_RANGE;
463 nav1_effective_range = nav1_range;
464 nav1_target_gs = ils.get_gsangle();
465 nav1_radial = ils.get_locheading();
466 while ( nav1_radial < 0.0 ) { nav1_radial += 360.0; }
467 while ( nav1_radial > 360.0 ) { nav1_radial -= 360.0; }
468 nav1_x = ils.get_x();
469 nav1_y = ils.get_y();
470 nav1_z = ils.get_z();
471 nav1_gs_x = ils.get_gs_x();
472 nav1_gs_y = ils.get_gs_y();
473 nav1_gs_z = ils.get_gs_z();
474 nav1_dme_x = ils.get_dme_x();
475 nav1_dme_y = ils.get_dme_y();
476 nav1_dme_z = ils.get_dme_z();
478 if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
479 globals->get_soundmgr()->remove( "nav1-vor-ident" );
481 FGSimpleSound *sound;
482 sound = morse.make_ident( nav1_trans_ident, LO_FREQUENCY );
483 sound->set_volume( 0.3 );
484 globals->get_soundmgr()->add( sound, "nav1-vor-ident" );
486 if ( globals->get_soundmgr()->exists( "nav1-dme-ident" ) ) {
487 globals->get_soundmgr()->remove( "nav1-dme-ident" );
489 sound = morse.make_ident( nav1_trans_ident, HI_FREQUENCY );
490 sound->set_volume( 0.3 );
491 globals->get_soundmgr()->add( sound, "nav1-dme-ident" );
493 int offset = (int)(sg_random() * 30.0);
494 nav1_play_count = offset / 4;
495 nav1_last_time = globals->get_time_params()->get_cur_time() -
497 cout << "offset = " << offset << " play_count = " << nav1_play_count
498 << " nav1_last_time = " << nav1_last_time << " current time = "
499 << globals->get_time_params()->get_cur_time() << endl;
501 cout << "Found an ils station in range" << endl;
502 cout << " id = " << ils.get_locident() << endl;
504 } else if ( current_navlist->query( lon, lat, elev, nav1_freq, &nav ) ) {
505 nav1_ident = nav.get_ident();
506 if ( last_nav1_ident != nav1_ident || !last_nav1_vor ) {
507 last_nav1_ident = nav1_ident;
508 last_nav1_vor = true;
509 nav1_trans_ident = nav.get_trans_ident();
512 nav1_has_dme = nav.get_has_dme();
514 nav1_loclon = nav.get_lon();
515 nav1_loclat = nav.get_lat();
516 nav1_elev = nav.get_elev();
517 nav1_magvar = nav.get_magvar();
518 nav1_range = nav.get_range();
519 nav1_effective_range = kludgeRange(nav1_elev, elev, nav1_range);
520 nav1_target_gs = 0.0;
521 nav1_radial = nav1_sel_radial;
522 nav1_x = nav1_dme_x = nav.get_x();
523 nav1_y = nav1_dme_y = nav.get_y();
524 nav1_z = nav1_dme_z = nav.get_z();
526 if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
527 globals->get_soundmgr()->remove( "nav1-vor-ident" );
529 FGSimpleSound *sound;
530 sound = morse.make_ident( nav1_trans_ident, LO_FREQUENCY );
531 sound->set_volume( 0.3 );
532 globals->get_soundmgr()->add( sound, "nav1-vor-ident" );
534 if ( globals->get_soundmgr()->exists( "nav1-dme-ident" ) ) {
535 globals->get_soundmgr()->remove( "nav1-dme-ident" );
537 sound = morse.make_ident( nav1_trans_ident, HI_FREQUENCY );
538 sound->set_volume( 0.3 );
539 globals->get_soundmgr()->add( sound, "nav1-dme-ident" );
541 int offset = (int)(sg_random() * 30.0);
542 nav1_play_count = offset / 4;
543 nav1_last_time = globals->get_time_params()->get_cur_time() -
545 cout << "offset = " << offset << " play_count = " << nav1_play_count
546 << " nav1_last_time = " << nav1_last_time << " current time = "
547 << globals->get_time_params()->get_cur_time() << endl;
549 cout << "Found a vor station in range" << endl;
550 cout << " id = " << nav.get_ident() << endl;
557 globals->get_soundmgr()->remove( "nav1-vor-ident" );
558 globals->get_soundmgr()->remove( "nav1-dme-ident" );
559 cout << "not picking up vor1. :-(" << endl;
562 if ( current_ilslist->query( lon, lat, elev, nav2_freq, &ils ) ) {
563 nav2_ident = ils.get_locident();
564 if ( last_nav2_ident != nav2_ident || last_nav2_vor ) {
565 last_nav2_ident = nav2_ident;
566 last_nav2_vor = false;
567 nav2_trans_ident = ils.get_trans_ident();
570 nav2_has_dme = ils.get_has_dme();
571 nav2_has_gs = ils.get_has_gs();
573 nav2_loclon = ils.get_loclon();
574 nav2_loclat = ils.get_loclat();
575 nav2_elev = ils.get_gselev();
577 nav2_range = FG_ILS_DEFAULT_RANGE;
578 nav2_effective_range = nav2_range;
579 nav2_target_gs = ils.get_gsangle();
580 nav2_radial = ils.get_locheading();
581 while ( nav2_radial < 0.0 ) { nav2_radial += 360.0; }
582 while ( nav2_radial > 360.0 ) { nav2_radial -= 360.0; }
583 nav2_x = ils.get_x();
584 nav2_y = ils.get_y();
585 nav2_z = ils.get_z();
586 nav2_gs_x = ils.get_gs_x();
587 nav2_gs_y = ils.get_gs_y();
588 nav2_gs_z = ils.get_gs_z();
589 nav2_dme_x = ils.get_dme_x();
590 nav2_dme_y = ils.get_dme_y();
591 nav2_dme_z = ils.get_dme_z();
592 // cout << "Found an ils station in range" << endl;
593 // cout << " id = " << ils.get_locident() << endl;
595 } else if ( current_navlist->query( lon, lat, elev, nav2_freq, &nav ) ) {
596 nav2_ident = nav.get_ident();
597 if ( last_nav2_ident != nav2_ident || !last_nav2_vor ) {
598 last_nav2_ident = nav2_ident;
599 last_nav2_vor = true;
600 nav2_trans_ident = nav.get_trans_ident();
603 nav2_has_dme = nav.get_has_dme();
604 nav2_has_dme = false;
605 nav2_loclon = nav.get_lon();
606 nav2_loclat = nav.get_lat();
607 nav2_elev = nav.get_elev();
608 nav2_magvar = nav.get_magvar();
609 nav2_range = nav.get_range();
610 nav2_effective_range = kludgeRange(nav2_elev, elev, nav2_range);
611 nav2_target_gs = 0.0;
612 nav2_radial = nav2_sel_radial;
613 nav2_x = nav2_dme_x = nav.get_x();
614 nav2_y = nav2_dme_y = nav.get_y();
615 nav2_z = nav2_dme_z = nav.get_z();
616 // cout << "Found a vor station in range" << endl;
617 // cout << " id = " << nav.get_ident() << endl;
624 // cout << "not picking up vor2. :-(" << endl;
628 if ( current_navlist->query( lon, lat, elev, adf_freq, &nav ) ) {
631 adf_lon = nav.get_lon();
632 adf_lat = nav.get_lat();
633 adf_elev = nav.get_elev();
634 adf_range = nav.get_range();
635 adf_effective_range = kludgeRange(adf_elev, elev, adf_range);
639 // cout << "Found an adf station in range" << endl;
640 // cout << " id = " << nav.get_ident() << endl;
643 // cout << "not picking up adf. :-(" << endl;
648 // return the amount of heading needle deflection, returns a value
649 // clamped to the range of ( -10 , 10 )
650 double FGRadioStack::get_nav1_heading_needle_deflection() const {
653 if ( nav1_inrange ) {
654 r = nav1_heading - nav1_radial;
655 // cout << "Radial = " << nav1_radial
656 // << " Bearing = " << nav1_heading << endl;
658 while ( r > 180.0 ) { r -= 360.0;}
659 while ( r < -180.0 ) { r += 360.0;}
660 if ( fabs(r) > 90.0 ) {
661 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
667 // According to Robin Peel, the ILS is 4x more sensitive than a vor
668 if ( nav1_loc ) { r *= 4.0; }
669 if ( r < -10.0 ) { r = -10.0; }
670 if ( r > 10.0 ) { r = 10.0; }
678 // return the amount of heading needle deflection, returns a value
679 // clamped to the range of ( -10 , 10 )
680 double FGRadioStack::get_nav2_heading_needle_deflection() const {
683 if ( nav2_inrange ) {
684 r = nav2_heading - nav2_radial;
685 // cout << "Radial = " << nav2_radial
686 // << " Bearing = " << nav2_heading << endl;
688 while (r> 180.0) r-=360.0;
689 while (r<-180.0) r+=360.0;
690 if ( fabs(r) > 90.0 )
691 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
692 // According to Robin Peel, the ILS is 4x more sensitive than a vor
693 if ( nav2_loc ) r *= 4.0;
694 if ( r < -10.0 ) r = -10.0;
695 if ( r > 10.0 ) r = 10.0;
703 // return the amount of glide slope needle deflection (.i.e. the
704 // number of degrees we are off the glide slope * 5.0
705 double FGRadioStack::get_nav1_gs_needle_deflection() const {
706 if ( nav1_inrange && nav1_has_gs ) {
707 double x = nav1_gs_dist;
708 double y = (FGBFI::getAltitude() - nav1_elev) * FEET_TO_METER;
709 double angle = atan2( y, x ) * RAD_TO_DEG;
710 return (nav1_target_gs - angle) * 5.0;
717 // return the amount of glide slope needle deflection (.i.e. the
718 // number of degrees we are off the glide slope * 5.0
719 double FGRadioStack::get_nav2_gs_needle_deflection() const {
720 if ( nav2_inrange && nav2_has_gs ) {
721 double x = nav2_gs_dist;
722 double y = (FGBFI::getAltitude() - nav2_elev) * FEET_TO_METER;
723 double angle = atan2( y, x ) * RAD_TO_DEG;
724 return (nav2_target_gs - angle) * 5.0;
732 * Return true if the NAV1 TO flag should be active.
735 FGRadioStack::get_nav1_to_flag () const
738 double offset = fabs(nav1_heading - nav1_radial);
742 return (offset <= 90.0 || offset >= 270.0);
750 * Return true if the NAV1 FROM flag should be active.
753 FGRadioStack::get_nav1_from_flag () const
756 double offset = fabs(nav1_heading - nav1_radial);
760 return (offset > 90.0 && offset < 270.0);
768 * Return true if the NAV2 TO flag should be active.
771 FGRadioStack::get_nav2_to_flag () const
774 double offset = fabs(nav2_heading - nav2_radial);
778 return (offset <= 90.0 || offset >= 270.0);
786 * Return true if the NAV2 FROM flag should be active.
789 FGRadioStack::get_nav2_from_flag () const
792 double offset = fabs(nav2_heading - nav2_radial);
796 return (offset > 90.0 && offset < 270.0);