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.
28 #include <stdio.h> // snprintf
30 #include <simgear/compiler.h>
31 #include <simgear/math/sg_random.h>
33 #include <Aircraft/aircraft.hxx>
34 #include <Navaids/ilslist.hxx>
35 #include <Navaids/mkrbeacons.hxx>
36 #include <Navaids/navlist.hxx>
37 #include <Time/FGEventMgr.hxx>
39 #include "radiostack.hxx"
44 static int nav1_play_count = 0;
45 static int nav2_play_count = 0;
46 static int adf_play_count = 0;
47 static time_t nav1_last_time = 0;
48 static time_t nav2_last_time = 0;
49 static time_t adf_last_time = 0;
52 FGRadioStack *current_radiostack;
56 * Boy, this is ugly! Make the VOR range vary by altitude difference.
58 static double kludgeRange ( double stationElev, double aircraftElev,
61 // Assume that the nominal range (usually
62 // 50nm) applies at a 5,000 ft difference.
64 double factor = ((aircraftElev*SG_METER_TO_FEET) - stationElev) / 5000.0;
65 double range = fabs(nominalRange * factor);
67 // Clamp the range to keep it sane; for
68 // now, never less than 25% or more than
69 // 500% of nominal range.
70 if (range < nominalRange/4.0) {
71 range = nominalRange/4.0;
72 } else if (range > nominalRange*5.0) {
73 range = nominalRange*5.0;
81 FGRadioStack::FGRadioStack() :
82 lon_node(fgGetNode("/position/longitude-deg", true)),
83 lat_node(fgGetNode("/position/latitude-deg", true)),
84 alt_node(fgGetNode("/position/altitude-ft", true)),
112 SGPath path( globals->get_fg_root() );
114 term.append( "Navaids/range.term" );
116 low.append( "Navaids/range.low" );
118 high.append( "Navaids/range.high" );
120 term_tbl = new SGInterpTable( term.str() );
121 low_tbl = new SGInterpTable( low.str() );
122 high_tbl = new SGInterpTable( high.str() );
123 dme_last_time.stamp();
128 FGRadioStack::~FGRadioStack()
130 unbind(); // FIXME: should be called externally
139 FGRadioStack::init ()
146 update(0); // FIXME: use dt
148 // Search radio database once per second
149 global_events.Register( "fgRadioSearch()",
150 current_radiostack, &FGRadioStack::search,
155 FGRadioStack::bind ()
158 fgTie("/radios/comm[0]/frequencies/selected-mhz", this,
159 &FGRadioStack::get_comm1_freq, &FGRadioStack::set_comm1_freq);
160 fgSetArchivable("/radios/comm[0]/frequencies/selected-mhz");
161 fgTie("/radios/comm[0]/frequencies/standby-mhz", this,
162 &FGRadioStack::get_comm1_alt_freq, &FGRadioStack::set_comm1_alt_freq);
163 fgSetArchivable("/radios/comm[0]/frequencies/standby-mhz");
164 fgTie("/radios/comm[0]/volume", this,
165 &FGRadioStack::get_comm1_vol_btn,
166 &FGRadioStack::set_comm1_vol_btn);
167 fgSetArchivable("/radios/comm[0]/volume");
168 fgTie("/radios/comm[0]/ident", this,
169 &FGRadioStack::get_comm1_ident_btn,
170 &FGRadioStack::set_comm1_ident_btn);
171 fgSetArchivable("/radios/comm[0]/ident");
173 fgTie("/radios/comm[1]/frequencies/selected-mhz", this,
174 &FGRadioStack::get_comm2_freq, &FGRadioStack::set_comm2_freq);
175 fgSetArchivable("/radios/comm[0]/frequencies/selected-mhz");
176 fgTie("/radios/comm[1]/frequencies/standby-mhz", this,
177 &FGRadioStack::get_comm2_alt_freq, &FGRadioStack::set_comm2_alt_freq);
178 fgSetArchivable("/radios/comm[0]/frequencies/standby-mhz");
179 fgTie("/radios/comm[1]/volume", this,
180 &FGRadioStack::get_comm2_vol_btn,
181 &FGRadioStack::set_comm2_vol_btn);
182 fgSetArchivable("/radios/comm[0]/volume");
183 fgTie("/radios/comm[1]/ident", this,
184 &FGRadioStack::get_comm2_ident_btn,
185 &FGRadioStack::set_comm2_ident_btn);
186 fgSetArchivable("/radios/comm[1]/ident");
188 fgTie("/radios/nav[0]/frequencies/selected-mhz", this,
189 &FGRadioStack::get_nav1_freq, &FGRadioStack::set_nav1_freq);
190 fgSetArchivable("/radios/nav[0]/frequencies/selected-mhz");
191 fgTie("/radios/nav[0]/frequencies/standby-mhz", this,
192 &FGRadioStack::get_nav1_alt_freq, &FGRadioStack::set_nav1_alt_freq);
193 fgSetArchivable("/radios/nav[0]/frequencies/standby-mhz");
194 fgTie("/radios/nav[0]/radials/selected-deg", this,
195 &FGRadioStack::get_nav1_sel_radial,
196 &FGRadioStack::set_nav1_sel_radial);
197 fgSetArchivable("/radios/nav[0]/radials/selected-deg");
198 fgTie("/radios/nav[0]/volume", this,
199 &FGRadioStack::get_nav1_vol_btn,
200 &FGRadioStack::set_nav1_vol_btn);
201 fgSetArchivable("/radios/nav[0]/volume");
202 fgTie("/radios/nav[0]/ident", this,
203 &FGRadioStack::get_nav1_ident_btn,
204 &FGRadioStack::set_nav1_ident_btn);
205 fgSetArchivable("/radios/nav[0]/ident");
208 fgTie("/radios/nav[0]/radials/actual-deg", this,
209 &FGRadioStack::get_nav1_radial);
210 fgTie("/radios/nav[0]/to-flag", this, &FGRadioStack::get_nav1_to_flag);
211 fgTie("/radios/nav[0]/from-flag", this, &FGRadioStack::get_nav1_from_flag);
212 fgTie("/radios/nav[0]/in-range", this, &FGRadioStack::get_nav1_inrange);
213 fgTie("/radios/nav[0]/heading-needle-deflection", this,
214 &FGRadioStack::get_nav1_heading_needle_deflection);
215 fgTie("/radios/nav[0]/gs-needle-deflection", this,
216 &FGRadioStack::get_nav1_gs_needle_deflection);
219 fgTie("/radios/nav[1]/frequencies/selected-mhz", this,
220 &FGRadioStack::get_nav2_freq, &FGRadioStack::set_nav2_freq);
221 fgSetArchivable("/radios/nav[1]/frequencies/selected-mhz");
222 fgTie("/radios/nav[1]/frequencies/standby-mhz", this,
223 &FGRadioStack::get_nav2_alt_freq, &FGRadioStack::set_nav2_alt_freq);
224 fgSetArchivable("/radios/nav[1]/frequencies/standby-mhz");
225 fgTie("/radios/nav[1]/radials/selected-deg", this,
226 &FGRadioStack::get_nav2_sel_radial,
227 &FGRadioStack::set_nav2_sel_radial);
228 fgSetArchivable("/radios/nav[1]/radials/selected-deg");
229 fgTie("/radios/nav[1]/volume", this,
230 &FGRadioStack::get_nav2_vol_btn,
231 &FGRadioStack::set_nav2_vol_btn);
232 fgSetArchivable("/radios/nav[1]/volume");
233 fgTie("/radios/nav[1]/ident", this,
234 &FGRadioStack::get_nav2_ident_btn,
235 &FGRadioStack::set_nav2_ident_btn);
236 fgSetArchivable("/radios/nav[1]/ident");
239 fgTie("/radios/nav[1]/radials/actual-deg", this,
240 &FGRadioStack::get_nav2_radial);
241 fgTie("/radios/nav[1]/to-flag", this, &FGRadioStack::get_nav2_to_flag);
242 fgTie("/radios/nav[1]/from-flag", this, &FGRadioStack::get_nav2_from_flag);
243 fgTie("/radios/nav[1]/in-range", this, &FGRadioStack::get_nav2_inrange);
244 fgTie("/radios/nav[1]/heading-needle-deflection", this,
245 &FGRadioStack::get_nav2_heading_needle_deflection);
246 fgTie("/radios/nav[1]/gs-needle-deflection", this,
247 &FGRadioStack::get_nav2_gs_needle_deflection);
250 fgTie("/radios/dme/frequencies/selected-khz", this,
251 &FGRadioStack::get_dme_freq, &FGRadioStack::set_dme_freq);
254 fgTie("/radios/dme/in-range", this, &FGRadioStack::get_dme_inrange);
255 fgTie("/radios/dme/distance-nm", this, &FGRadioStack::get_dme_dist);
256 fgTie("/radios/dme/speed-kt", this, &FGRadioStack::get_dme_spd);
257 fgTie("/radios/dme/ete-min", this, &FGRadioStack::get_dme_ete);
260 fgTie("/radios/adf/frequencies/selected-khz", this,
261 &FGRadioStack::get_adf_freq, &FGRadioStack::set_adf_freq);
262 fgSetArchivable("/radios/adf/frequencies/selected-khz");
263 fgTie("/radios/adf/frequencies/standby-khz", this,
264 &FGRadioStack::get_adf_alt_freq, &FGRadioStack::set_adf_alt_freq);
265 fgSetArchivable("/radios/adf/frequencies/standby-khz");
266 fgTie("/radios/adf/rotation-deg", this,
267 &FGRadioStack::get_adf_rotation, &FGRadioStack::set_adf_rotation);
268 fgSetArchivable("/radios/adf/rotation-deg");
269 fgTie("/radios/adf/volume", this,
270 &FGRadioStack::get_adf_vol_btn,
271 &FGRadioStack::set_adf_vol_btn);
272 fgSetArchivable("/radios/adf/volume");
273 fgTie("/radios/adf/ident", this,
274 &FGRadioStack::get_adf_ident_btn,
275 &FGRadioStack::set_adf_ident_btn);
276 fgSetArchivable("/radios/adf/ident");
278 fgTie("/radios/marker-beacon/inner", this,
279 &FGRadioStack::get_inner_blink);
280 fgTie("/radios/marker-beacon/middle", this,
281 &FGRadioStack::get_middle_blink);
282 fgTie("/radios/marker-beacon/outer", this,
283 &FGRadioStack::get_outer_blink);
287 FGRadioStack::unbind ()
289 fgUntie("/radios/comm[0]/frequencies/selected-mhz");
290 fgUntie("/radios/comm[0]/frequencies/standby-mhz");
291 fgUntie("/radios/comm[0]/on");
292 fgUntie("/radios/comm[0]/ident");
294 fgUntie("/radios/comm[1]/frequencies/selected-mhz");
295 fgUntie("/radios/comm[1]/frequencies/standby-mhz");
296 fgUntie("/radios/comm[1]/on");
297 fgUntie("/radios/comm[1]/ident");
299 fgUntie("/radios/nav[0]/frequencies/selected-mhz");
300 fgUntie("/radios/nav[0]/frequencies/standby-mhz");
301 fgUntie("/radios/nav[0]/radials/actual-deg");
302 fgUntie("/radios/nav[0]/radials/selected-deg");
303 fgUntie("/radios/nav[0]/on");
304 fgUntie("/radios/nav[0]/ident");
305 fgUntie("/radios/nav[0]/to-flag");
306 fgUntie("/radios/nav[0]/from-flag");
307 fgUntie("/radios/nav[0]/in-range");
308 fgUntie("/radios/nav[0]/heading-needle-deflection");
309 fgUntie("/radios/nav[0]/gs-needle-deflection");
311 fgUntie("/radios/nav[1]/frequencies/selected-mhz");
312 fgUntie("/radios/nav[1]/frequencies/standby-mhz");
313 fgUntie("/radios/nav[1]/radials/actual-deg");
314 fgUntie("/radios/nav[1]/radials/selected-deg");
315 fgUntie("/radios/nav[1]/on");
316 fgUntie("/radios/nav[1]/ident");
317 fgUntie("/radios/nav[1]/to-flag");
318 fgUntie("/radios/nav[1]/from-flag");
319 fgUntie("/radios/nav[1]/in-range");
320 fgUntie("/radios/nav[1]/heading-needle-deflection");
321 fgUntie("/radios/nav[1]/gs-needle-deflection");
323 fgUntie("/radios/dme/frequencies/selected-khz");
326 fgUntie("/radios/dme/in-range");
327 fgUntie("/radios/dme/distance-nm");
328 fgUntie("/radios/dme/speed-kt");
329 fgUntie("/radios/dme/ete-min");
331 fgUntie("/radios/adf/frequencies/selected-khz");
332 fgUntie("/radios/adf/frequencies/standby-khz");
333 fgUntie("/radios/adf/rotation-deg");
334 fgUntie("/radios/adf/on");
335 fgUntie("/radios/adf/ident");
337 fgUntie("/radios/marker-beacon/inner");
338 fgUntie("/radios/marker-beacon/middle");
339 fgUntie("/radios/marker-beacon/outer");
343 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
344 double FGRadioStack::adjustNavRange( double stationElev, double aircraftElev,
345 double nominalRange )
347 // extend out actual usable range to be 1.3x the published safe range
348 const double usability_factor = 1.3;
350 // assumptions we model the standard service volume, plus
351 // ... rather than specifying a cylinder, we model a cone that
352 // contains the cylinder. Then we put an upside down cone on top
353 // to model diminishing returns at too-high altitudes.
355 // altitude difference
356 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
357 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
358 // << " station elev = " << stationElev << endl;
360 if ( nominalRange < 25.0 + SG_EPSILON ) {
361 // Standard Terminal Service Volume
362 return term_tbl->interpolate( alt ) * usability_factor;
363 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
364 // Standard Low Altitude Service Volume
365 // table is based on range of 40, scale to actual range
366 return low_tbl->interpolate( alt ) * nominalRange / 40.0
369 // Standard High Altitude Service Volume
370 // table is based on range of 130, scale to actual range
371 return high_tbl->interpolate( alt ) * nominalRange / 130.0
377 // model standard ILS service volumes as per AIM 1-1-9
378 double FGRadioStack::adjustILSRange( double stationElev, double aircraftElev,
379 double offsetDegrees, double distance )
381 // assumptions we model the standard service volume, plus
383 // altitude difference
384 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
385 double offset = fabs( offsetDegrees );
388 return FG_ILS_DEFAULT_RANGE;
389 } else if ( offset < 35 ) {
390 return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
391 } else if ( offset < 45 ) {
392 return (45 - offset);
393 } else if ( offset > 170 ) {
394 return FG_ILS_DEFAULT_RANGE;
395 } else if ( offset > 145 ) {
396 return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
397 } else if ( offset > 135 ) {
398 return (offset - 135);
405 // Update the various nav values based on position and valid tuned in navs
407 FGRadioStack::update(double dt)
409 double lon = lon_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
410 double lat = lat_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
411 double elev = alt_node->getDoubleValue() * SG_FEET_TO_METER;
415 Point3D aircraft = sgGeodToCart( Point3D( lon, lat, elev ) );
419 ////////////////////////////////////////////////////////////////////////
421 ////////////////////////////////////////////////////////////////////////
424 station = Point3D( nav1_x, nav1_y, nav1_z );
425 nav1_loc_dist = aircraft.distance3D( station );
428 station = Point3D( nav1_gs_x, nav1_gs_y, nav1_gs_z );
429 nav1_gs_dist = aircraft.distance3D( station );
435 geo_inverse_wgs_84( elev, lat * SGD_RADIANS_TO_DEGREES, lon * SGD_RADIANS_TO_DEGREES,
436 nav1_loclat, nav1_loclon,
438 // cout << "az1 = " << az1 << " magvar = " << nav1_magvar << endl;
439 nav1_heading = az1 - nav1_magvar;
440 // cout << " heading = " << nav1_heading
441 // << " dist = " << nav1_dist << endl;
444 double offset = nav1_heading - nav1_radial;
445 while ( offset < -180.0 ) { offset += 360.0; }
446 while ( offset > 180.0 ) { offset -= 360.0; }
447 // cout << "ils offset = " << offset << endl;
448 nav1_effective_range = adjustILSRange(nav1_elev, elev, offset,
449 nav1_loc_dist * SG_METER_TO_NM );
451 nav1_effective_range = adjustNavRange(nav1_elev, elev, nav1_range);
453 // cout << "nav1 range = " << nav1_effective_range
454 // << " (" << nav1_range << ")" << endl;
456 if ( nav1_loc_dist < nav1_effective_range * SG_NM_TO_METER ) {
458 } else if ( nav1_loc_dist < 2 * nav1_effective_range * SG_NM_TO_METER ) {
459 nav1_inrange = sg_random() <
460 ( 2 * nav1_effective_range * SG_NM_TO_METER - nav1_loc_dist ) /
461 (nav1_effective_range * SG_NM_TO_METER);
463 nav1_inrange = false;
467 nav1_radial = nav1_sel_radial;
470 nav1_inrange = false;
471 // cout << "not picking up vor. :-(" << endl;
474 #ifdef ENABLE_AUDIO_SUPPORT
475 if ( nav1_valid && nav1_inrange ) {
476 // play station ident via audio system if on + ident,
477 // otherwise turn it off
478 if ( nav1_vol_btn > 0.1 && nav1_ident_btn ) {
479 FGSimpleSound *sound;
480 sound = globals->get_soundmgr()->find( "nav1-vor-ident" );
481 if ( sound != NULL ) {
482 sound->set_volume( nav1_vol_btn );
484 SG_LOG( SG_COCKPIT, SG_ALERT,
485 "Can't find nav1-vor-ident sound" );
487 sound = globals->get_soundmgr()->find( "nav1-dme-ident" );
488 if ( sound != NULL ) {
489 sound->set_volume( nav1_vol_btn );
491 SG_LOG( SG_COCKPIT, SG_ALERT,
492 "Can't find nav1-dme-ident sound" );
494 // cout << "nav1_last_time = " << nav1_last_time << " ";
495 // cout << "cur_time = " << globals->get_time_params()->get_cur_time();
496 if ( nav1_last_time <
497 globals->get_time_params()->get_cur_time() - 30 ) {
498 nav1_last_time = globals->get_time_params()->get_cur_time();
501 // cout << " nav1_play_count = " << nav1_play_count << endl;
502 // cout << "playing = "
503 // << globals->get_soundmgr()->is_playing("nav1-vor-ident")
505 if ( nav1_play_count < 4 ) {
507 if ( !globals->get_soundmgr()->is_playing("nav1-vor-ident") ) {
508 globals->get_soundmgr()->play_once( "nav1-vor-ident" );
511 } else if ( nav1_play_count < 5 && nav1_has_dme ) {
513 if ( !globals->get_soundmgr()->is_playing("nav1-vor-ident") &&
514 !globals->get_soundmgr()->is_playing("nav1-dme-ident") ) {
515 globals->get_soundmgr()->play_once( "nav1-dme-ident" );
520 globals->get_soundmgr()->stop( "nav1-vor-ident" );
521 globals->get_soundmgr()->stop( "nav1-dme-ident" );
527 ////////////////////////////////////////////////////////////////////////
529 ////////////////////////////////////////////////////////////////////////
532 station = Point3D( nav2_x, nav2_y, nav2_z );
533 nav2_loc_dist = aircraft.distance3D( station );
536 station = Point3D( nav2_gs_x, nav2_gs_y, nav2_gs_z );
537 nav2_gs_dist = aircraft.distance3D( station );
543 geo_inverse_wgs_84( elev, lat * SGD_RADIANS_TO_DEGREES, lon * SGD_RADIANS_TO_DEGREES,
544 nav2_loclat, nav2_loclon,
546 nav2_heading = az1 - nav2_magvar;
547 // cout << " heading = " << nav2_heading
548 // << " dist = " << nav2_dist << endl;
551 double offset = nav2_heading - nav2_radial;
552 while ( offset < -180.0 ) { offset += 360.0; }
553 while ( offset > 180.0 ) { offset -= 360.0; }
554 // cout << "ils offset = " << offset << endl;
555 nav2_effective_range = adjustILSRange(nav2_elev, elev, offset,
556 nav2_loc_dist * SG_METER_TO_NM );
558 nav2_effective_range = adjustNavRange(nav2_elev, elev, nav2_range);
560 // cout << "nav2 range = " << nav2_effective_range
561 // << " (" << nav2_range << ")" << endl;
563 if ( nav2_loc_dist < nav2_effective_range * SG_NM_TO_METER ) {
565 } else if ( nav2_loc_dist < 2 * nav2_effective_range * SG_NM_TO_METER ) {
566 nav2_inrange = sg_random() <
567 ( 2 * nav2_effective_range * SG_NM_TO_METER - nav2_loc_dist ) /
568 (nav2_effective_range * SG_NM_TO_METER);
570 nav2_inrange = false;
574 nav2_radial = nav2_sel_radial;
577 nav2_inrange = false;
578 // cout << "not picking up vor. :-(" << endl;
581 #ifdef ENABLE_AUDIO_SUPPORT
582 if ( nav2_valid && nav2_inrange ) {
583 // play station ident via audio system if on + ident,
584 // otherwise turn it off
585 if ( nav2_vol_btn > 0.1 && nav2_ident_btn ) {
586 FGSimpleSound *sound;
587 sound = globals->get_soundmgr()->find( "nav2-vor-ident" );
588 if ( sound != NULL ) {
589 sound->set_volume( nav2_vol_btn );
591 SG_LOG( SG_COCKPIT, SG_ALERT,
592 "Can't find nav2-vor-ident sound" );
594 sound = globals->get_soundmgr()->find( "nav2-dme-ident" );
595 if ( sound != NULL ) {
596 sound->set_volume( nav2_vol_btn );
598 SG_LOG( SG_COCKPIT, SG_ALERT,
599 "Can't find nav2-dme-ident sound" );
601 if ( nav2_last_time <
602 globals->get_time_params()->get_cur_time() - 30 ) {
603 nav2_last_time = globals->get_time_params()->get_cur_time();
606 if ( nav2_play_count < 4 ) {
608 if ( !globals->get_soundmgr()->is_playing("nav2-vor-ident") ) {
609 globals->get_soundmgr()->play_once( "nav2-vor-ident" );
612 } else if ( nav2_play_count < 5 && nav2_has_dme ) {
614 if ( !globals->get_soundmgr()->is_playing("nav2-vor-ident") &&
615 !globals->get_soundmgr()->is_playing("nav2-dme-ident") ) {
616 globals->get_soundmgr()->play_once( "nav2-dme-ident" );
621 globals->get_soundmgr()->stop( "nav2-vor-ident" );
622 globals->get_soundmgr()->stop( "nav2-dme-ident" );
628 ////////////////////////////////////////////////////////////////////////
630 ////////////////////////////////////////////////////////////////////////
633 station = Point3D( dme_x, dme_y, dme_z );
634 dme_dist = aircraft.distance3D( station ) * SG_METER_TO_NM;
635 dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
636 if (dme_dist < dme_effective_range * SG_NM_TO_METER) {
638 } else if (dme_dist < 2 * dme_effective_range * SG_NM_TO_METER) {
639 dme_inrange = sg_random() <
640 (2 * dme_effective_range * SG_NM_TO_METER - dme_dist) /
641 (dme_effective_range * SG_NM_TO_METER);
646 SGTimeStamp current_time;
647 station = Point3D( dme_x, dme_y, dme_z );
648 dme_dist = aircraft.distance3D( station ) * SG_METER_TO_NM;
649 current_time.stamp();
650 long dMs = (current_time - dme_last_time) / 1000;
651 // Update every second
653 double dDist = dme_dist - dme_prev_dist;
654 dme_spd = fabs((dDist/dMs) * 3600000);
655 // FIXME: the panel should be able to
659 dme_ete = fabs((dme_dist/dme_spd) * 60.0);
660 // FIXME: the panel should be able to
664 dme_prev_dist = dme_dist;
665 dme_last_time.stamp();
675 ////////////////////////////////////////////////////////////////////////
677 ////////////////////////////////////////////////////////////////////////
680 // staightline distance
681 station = Point3D( adf_x, adf_y, adf_z );
682 adf_dist = aircraft.distance3D( station );
685 geo_inverse_wgs_84( elev, lat * SGD_RADIANS_TO_DEGREES, lon * SGD_RADIANS_TO_DEGREES,
689 // cout << " heading = " << nav2_heading
690 // << " dist = " << nav2_dist << endl;
692 adf_effective_range = kludgeRange(adf_elev, elev, adf_range);
693 if ( adf_dist < adf_effective_range * SG_NM_TO_METER ) {
695 } else if ( adf_dist < 2 * adf_effective_range * SG_NM_TO_METER ) {
696 adf_inrange = sg_random() <
697 ( 2 * adf_effective_range * SG_NM_TO_METER - adf_dist ) /
698 (adf_effective_range * SG_NM_TO_METER);
706 #ifdef ENABLE_AUDIO_SUPPORT
707 if ( adf_valid && adf_inrange ) {
708 // play station ident via audio system if on + ident,
709 // otherwise turn it off
710 if ( adf_vol_btn > 0.1 && adf_ident_btn ) {
711 FGSimpleSound *sound;
712 sound = globals->get_soundmgr()->find( "adf-ident" );
713 if ( sound != NULL ) {
714 sound->set_volume( adf_vol_btn );
716 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find adf-ident sound" );
719 globals->get_time_params()->get_cur_time() - 30 ) {
720 adf_last_time = globals->get_time_params()->get_cur_time();
723 if ( adf_play_count < 4 ) {
725 if ( !globals->get_soundmgr()->is_playing("adf-ident") ) {
726 globals->get_soundmgr()->play_once( "adf-ident" );
731 globals->get_soundmgr()->stop( "adf-ident" );
736 // marker beacon blinking
737 bool light_on = ( outer_blink || middle_blink || inner_blink );
741 if ( light_on && (current - blink > 400000) ) {
744 } else if ( !light_on && (current - blink > 100000) ) {
749 if ( outer_marker ) {
750 outer_blink = light_on;
755 if ( middle_marker ) {
756 middle_blink = light_on;
758 middle_blink = false;
761 if ( inner_marker ) {
762 inner_blink = light_on;
767 // cout << outer_blink << " " << middle_blink << " " << inner_blink << endl;
771 // Update current nav/adf radio stations based on current postition
772 void FGRadioStack::search()
774 static FGMkrBeacon::fgMkrBeacType last_beacon = FGMkrBeacon::NOBEACON;
776 double lon = lon_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
777 double lat = lat_node->getDoubleValue() * SGD_DEGREES_TO_RADIANS;
778 double elev = alt_node->getDoubleValue() * SG_FEET_TO_METER;
780 // FIXME: the panel should handle this
781 // don't worry about overhead for now,
782 // since this is handled only periodically
783 int dme_switch_pos = fgGetInt("/radios/dme/switch-position");
784 if (dme_switch_pos == 0) {
787 } else if (dme_switch_pos == 1) {
788 if (dme_freq != nav1_freq) {
789 dme_freq = nav1_freq;
792 } else if (dme_switch_pos == 3) {
793 if (dme_freq != nav2_freq) {
794 dme_freq = nav2_freq;
802 static string last_nav1_ident = "";
803 static string last_nav2_ident = "";
804 static string last_adf_ident = "";
805 static bool last_nav1_vor = false;
806 static bool last_nav2_vor = false;
808 ////////////////////////////////////////////////////////////////////////
810 ////////////////////////////////////////////////////////////////////////
812 if ( current_ilslist->query( lon, lat, elev, nav1_freq, &ils ) ) {
813 nav1_ident = ils.get_locident();
815 if ( last_nav1_ident != nav1_ident || last_nav1_vor ) {
816 nav1_trans_ident = ils.get_trans_ident();
817 last_nav1_ident = nav1_ident;
818 last_nav1_vor = false;
820 nav1_has_dme = ils.get_has_dme();
821 nav1_has_gs = ils.get_has_gs();
823 nav1_loclon = ils.get_loclon();
824 nav1_loclat = ils.get_loclat();
825 nav1_gslon = ils.get_gslon();
826 nav1_gslat = ils.get_gslat();
827 nav1_elev = ils.get_gselev();
829 nav1_range = FG_ILS_DEFAULT_RANGE;
830 nav1_effective_range = nav1_range;
831 nav1_target_gs = ils.get_gsangle();
832 nav1_radial = ils.get_locheading();
833 while ( nav1_radial < 0.0 ) { nav1_radial += 360.0; }
834 while ( nav1_radial > 360.0 ) { nav1_radial -= 360.0; }
835 nav1_x = ils.get_x();
836 nav1_y = ils.get_y();
837 nav1_z = ils.get_z();
838 nav1_gs_x = ils.get_gs_x();
839 nav1_gs_y = ils.get_gs_y();
840 nav1_gs_z = ils.get_gs_z();
842 #ifdef ENABLE_AUDIO_SUPPORT
843 if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
844 globals->get_soundmgr()->remove( "nav1-vor-ident" );
846 FGSimpleSound *sound;
847 sound = morse.make_ident( nav1_trans_ident, LO_FREQUENCY );
848 sound->set_volume( 0.3 );
849 globals->get_soundmgr()->add( sound, "nav1-vor-ident" );
851 if ( globals->get_soundmgr()->exists( "nav1-dme-ident" ) ) {
852 globals->get_soundmgr()->remove( "nav1-dme-ident" );
854 sound = morse.make_ident( nav1_trans_ident, HI_FREQUENCY );
855 sound->set_volume( 0.3 );
856 globals->get_soundmgr()->add( sound, "nav1-dme-ident" );
858 int offset = (int)(sg_random() * 30.0);
859 nav1_play_count = offset / 4;
860 nav1_last_time = globals->get_time_params()->get_cur_time() -
862 // cout << "offset = " << offset << " play_count = "
863 // << nav1_play_count
864 // << " nav1_last_time = " << nav1_last_time
865 // << " current time = "
866 // << globals->get_time_params()->get_cur_time() << endl;
869 // cout << "Found an ils station in range" << endl;
870 // cout << " id = " << ils.get_locident() << endl;
872 } else if ( current_navlist->query( lon, lat, elev, nav1_freq, &nav ) ) {
873 nav1_ident = nav.get_ident();
875 if ( last_nav1_ident != nav1_ident || !last_nav1_vor ) {
876 last_nav1_ident = nav1_ident;
877 last_nav1_vor = true;
878 nav1_trans_ident = nav.get_trans_ident();
880 nav1_has_dme = nav.get_has_dme();
882 nav1_loclon = nav.get_lon();
883 nav1_loclat = nav.get_lat();
884 nav1_elev = nav.get_elev();
885 nav1_magvar = nav.get_magvar();
886 nav1_range = nav.get_range();
887 nav1_effective_range = adjustNavRange(nav1_elev, elev, nav1_range);
888 nav1_target_gs = 0.0;
889 nav1_radial = nav1_sel_radial;
890 nav1_x = nav.get_x();
891 nav1_y = nav.get_y();
892 nav1_z = nav.get_z();
894 #ifdef ENABLE_AUDIO_SUPPORT
895 if ( globals->get_soundmgr()->exists( "nav1-vor-ident" ) ) {
896 globals->get_soundmgr()->remove( "nav1-vor-ident" );
898 FGSimpleSound *sound;
899 sound = morse.make_ident( nav1_trans_ident, LO_FREQUENCY );
900 sound->set_volume( 0.3 );
901 if ( globals->get_soundmgr()->add( sound, "nav1-vor-ident" ) ) {
902 // cout << "Added nav1-vor-ident sound" << endl;
904 // cout << "Failed to add v1-vor-ident sound" << endl;
907 if ( globals->get_soundmgr()->exists( "nav1-dme-ident" ) ) {
908 globals->get_soundmgr()->remove( "nav1-dme-ident" );
910 sound = morse.make_ident( nav1_trans_ident, HI_FREQUENCY );
911 sound->set_volume( 0.3 );
912 globals->get_soundmgr()->add( sound, "nav1-dme-ident" );
914 int offset = (int)(sg_random() * 30.0);
915 nav1_play_count = offset / 4;
916 nav1_last_time = globals->get_time_params()->get_cur_time() -
918 // cout << "offset = " << offset << " play_count = "
919 // << nav1_play_count << " nav1_last_time = "
920 // << nav1_last_time << " current time = "
921 // << globals->get_time_params()->get_cur_time() << endl;
924 // cout << "Found a vor station in range" << endl;
925 // cout << " id = " << nav.get_ident() << endl;
931 nav1_trans_ident = "";
932 last_nav1_ident = "";
933 #ifdef ENABLE_AUDIO_SUPPORT
934 if ( ! globals->get_soundmgr()->remove( "nav1-vor-ident" ) ) {
935 // cout << "Failed to remove nav1-vor-ident sound" << endl;
937 globals->get_soundmgr()->remove( "nav1-dme-ident" );
939 // cout << "not picking up vor1. :-(" << endl;
943 ////////////////////////////////////////////////////////////////////////
945 ////////////////////////////////////////////////////////////////////////
947 if ( current_ilslist->query( lon, lat, elev, nav2_freq, &ils ) ) {
948 nav2_ident = ils.get_locident();
950 if ( last_nav2_ident != nav2_ident || last_nav2_vor ) {
951 last_nav2_ident = nav2_ident;
952 last_nav2_vor = false;
953 nav2_trans_ident = ils.get_trans_ident();
955 nav2_has_dme = ils.get_has_dme();
956 nav2_has_gs = ils.get_has_gs();
958 nav2_loclon = ils.get_loclon();
959 nav2_loclat = ils.get_loclat();
960 nav2_elev = ils.get_gselev();
962 nav2_range = FG_ILS_DEFAULT_RANGE;
963 nav2_effective_range = nav2_range;
964 nav2_target_gs = ils.get_gsangle();
965 nav2_radial = ils.get_locheading();
966 while ( nav2_radial < 0.0 ) { nav2_radial += 360.0; }
967 while ( nav2_radial > 360.0 ) { nav2_radial -= 360.0; }
968 nav2_x = ils.get_x();
969 nav2_y = ils.get_y();
970 nav2_z = ils.get_z();
971 nav2_gs_x = ils.get_gs_x();
972 nav2_gs_y = ils.get_gs_y();
973 nav2_gs_z = ils.get_gs_z();
975 #ifdef ENABLE_AUDIO_SUPPORT
976 if ( globals->get_soundmgr()->exists( "nav2-vor-ident" ) ) {
977 globals->get_soundmgr()->remove( "nav2-vor-ident" );
979 FGSimpleSound *sound;
980 sound = morse.make_ident( nav2_trans_ident, LO_FREQUENCY );
981 sound->set_volume( 0.3 );
982 globals->get_soundmgr()->add( sound, "nav2-vor-ident" );
984 if ( globals->get_soundmgr()->exists( "nav2-dme-ident" ) ) {
985 globals->get_soundmgr()->remove( "nav2-dme-ident" );
987 sound = morse.make_ident( nav2_trans_ident, HI_FREQUENCY );
988 sound->set_volume( 0.3 );
989 globals->get_soundmgr()->add( sound, "nav2-dme-ident" );
991 int offset = (int)(sg_random() * 30.0);
992 nav2_play_count = offset / 4;
993 nav2_last_time = globals->get_time_params()->get_cur_time() -
995 // cout << "offset = " << offset << " play_count = "
996 // << nav2_play_count << " nav2_last_time = "
997 // << nav2_last_time << " current time = "
998 // << globals->get_time_params()->get_cur_time() << endl;
1001 // cout << "Found an ils station in range" << endl;
1002 // cout << " id = " << ils.get_locident() << endl;
1004 } else if ( current_navlist->query( lon, lat, elev, nav2_freq, &nav ) ) {
1005 nav2_ident = nav.get_ident();
1007 if ( last_nav2_ident != nav2_ident || !last_nav2_vor ) {
1008 last_nav2_ident = nav2_ident;
1009 last_nav2_vor = true;
1010 nav2_trans_ident = nav.get_trans_ident();
1012 nav2_has_dme = nav.get_has_dme();
1013 nav2_has_dme = false;
1014 nav2_loclon = nav.get_lon();
1015 nav2_loclat = nav.get_lat();
1016 nav2_elev = nav.get_elev();
1017 nav2_magvar = nav.get_magvar();
1018 nav2_range = nav.get_range();
1019 nav2_effective_range = adjustNavRange(nav2_elev, elev, nav2_range);
1020 nav2_target_gs = 0.0;
1021 nav2_radial = nav2_sel_radial;
1022 nav2_x = nav.get_x();
1023 nav2_y = nav.get_y();
1024 nav2_z = nav.get_z();
1026 #ifdef ENABLE_AUDIO_SUPPORT
1027 if ( globals->get_soundmgr()->exists( "nav2-vor-ident" ) ) {
1028 globals->get_soundmgr()->remove( "nav2-vor-ident" );
1030 FGSimpleSound *sound;
1031 sound = morse.make_ident( nav2_trans_ident, LO_FREQUENCY );
1032 sound->set_volume( 0.3 );
1033 globals->get_soundmgr()->add( sound, "nav2-vor-ident" );
1035 if ( globals->get_soundmgr()->exists( "nav2-dme-ident" ) ) {
1036 globals->get_soundmgr()->remove( "nav2-dme-ident" );
1038 sound = morse.make_ident( nav2_trans_ident, HI_FREQUENCY );
1039 sound->set_volume( 0.3 );
1040 globals->get_soundmgr()->add( sound, "nav2-dme-ident" );
1042 int offset = (int)(sg_random() * 30.0);
1043 nav2_play_count = offset / 4;
1044 nav2_last_time = globals->get_time_params()->get_cur_time() -
1046 // cout << "offset = " << offset << " play_count = "
1047 // << nav2_play_count << " nav2_last_time = "
1048 // << nav2_last_time << " current time = "
1049 // << globals->get_time_params()->get_cur_time() << endl;
1052 // cout << "Found a vor station in range" << endl;
1053 // cout << " id = " << nav.get_ident() << endl;
1059 nav2_trans_ident = "";
1060 last_nav2_ident = "";
1061 #ifdef ENABLE_AUDIO_SUPPORT
1062 globals->get_soundmgr()->remove( "nav2-vor-ident" );
1063 globals->get_soundmgr()->remove( "nav2-dme-ident" );
1065 // cout << "not picking up vor1. :-(" << endl;
1069 ////////////////////////////////////////////////////////////////////////
1071 ////////////////////////////////////////////////////////////////////////
1073 if ( current_ilslist->query( lon, lat, elev, dme_freq, &ils ) ) {
1074 if (ils.get_has_dme()) {
1076 dme_lon = ils.get_loclon();
1077 dme_lat = ils.get_loclat();
1078 dme_elev = ils.get_gselev();
1079 dme_range = FG_ILS_DEFAULT_RANGE;
1080 dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
1081 dme_x = ils.get_dme_x();
1082 dme_y = ils.get_dme_y();
1083 dme_z = ils.get_dme_z();
1085 } else if ( current_navlist->query( lon, lat, elev, dme_freq, &nav ) ) {
1086 if (nav.get_has_dme()) {
1088 dme_lon = nav.get_lon();
1089 dme_lat = nav.get_lat();
1090 dme_elev = nav.get_elev();
1091 dme_range = nav.get_range();
1092 dme_effective_range = kludgeRange(dme_elev, elev, dme_range);
1093 dme_x = nav.get_x();
1094 dme_y = nav.get_y();
1095 dme_z = nav.get_z();
1103 ////////////////////////////////////////////////////////////////////////
1105 ////////////////////////////////////////////////////////////////////////
1107 FGMkrBeacon::fgMkrBeacType beacon_type
1108 = current_beacons->query( lon * SGD_RADIANS_TO_DEGREES,
1109 lat * SGD_RADIANS_TO_DEGREES, elev );
1111 outer_marker = middle_marker = inner_marker = false;
1113 if ( beacon_type == FGMkrBeacon::OUTER ) {
1114 outer_marker = true;
1115 // cout << "OUTER MARKER" << endl;
1116 #ifdef ENABLE_AUDIO_SUPPORT
1117 if ( last_beacon != FGMkrBeacon::OUTER ) {
1118 if ( ! globals->get_soundmgr()->exists( "outer-marker" ) ) {
1119 FGSimpleSound *sound = beacon.get_outer();
1120 sound->set_volume( 0.3 );
1121 globals->get_soundmgr()->add( sound, "outer-marker" );
1123 if ( !globals->get_soundmgr()->is_playing("outer-marker") ) {
1124 globals->get_soundmgr()->play_looped( "outer-marker" );
1128 } else if ( beacon_type == FGMkrBeacon::MIDDLE ) {
1129 middle_marker = true;
1130 // cout << "MIDDLE MARKER" << endl;
1131 #ifdef ENABLE_AUDIO_SUPPORT
1132 if ( last_beacon != FGMkrBeacon::MIDDLE ) {
1133 if ( ! globals->get_soundmgr()->exists( "middle-marker" ) ) {
1134 FGSimpleSound *sound = beacon.get_middle();
1135 sound->set_volume( 0.3 );
1136 globals->get_soundmgr()->add( sound, "middle-marker" );
1138 if ( !globals->get_soundmgr()->is_playing("middle-marker") ) {
1139 globals->get_soundmgr()->play_looped( "middle-marker" );
1143 } else if ( beacon_type == FGMkrBeacon::INNER ) {
1144 inner_marker = true;
1145 // cout << "INNER MARKER" << endl;
1146 #ifdef ENABLE_AUDIO_SUPPORT
1147 if ( last_beacon != FGMkrBeacon::INNER ) {
1148 if ( ! globals->get_soundmgr()->exists( "inner-marker" ) ) {
1149 FGSimpleSound *sound = beacon.get_inner();
1150 sound->set_volume( 0.3 );
1151 globals->get_soundmgr()->add( sound, "inner-marker" );
1153 if ( !globals->get_soundmgr()->is_playing("inner-marker") ) {
1154 globals->get_soundmgr()->play_looped( "inner-marker" );
1159 // cout << "no marker" << endl;
1160 #ifdef ENABLE_AUDIO_SUPPORT
1161 globals->get_soundmgr()->stop( "outer-marker" );
1162 globals->get_soundmgr()->stop( "middle-marker" );
1163 globals->get_soundmgr()->stop( "inner-marker" );
1166 last_beacon = beacon_type;
1169 ////////////////////////////////////////////////////////////////////////
1171 ////////////////////////////////////////////////////////////////////////
1173 if ( current_navlist->query( lon, lat, elev, adf_freq, &nav ) ) {
1175 snprintf( freq, 10, "%.0f", adf_freq );
1177 adf_ident += nav.get_ident();
1178 // cout << "adf ident = " << adf_ident << endl;
1180 if ( last_adf_ident != adf_ident ) {
1181 last_adf_ident = adf_ident;
1183 adf_trans_ident = nav.get_trans_ident();
1184 adf_lon = nav.get_lon();
1185 adf_lat = nav.get_lat();
1186 adf_elev = nav.get_elev();
1187 adf_range = nav.get_range();
1188 adf_effective_range = kludgeRange(adf_elev, elev, adf_range);
1189 adf_x = nav.get_x();
1190 adf_y = nav.get_y();
1191 adf_z = nav.get_z();
1193 #ifdef ENABLE_AUDIO_SUPPORT
1194 if ( globals->get_soundmgr()->exists( "adf-ident" ) ) {
1195 globals->get_soundmgr()->remove( "adf-ident" );
1197 FGSimpleSound *sound;
1198 sound = morse.make_ident( adf_trans_ident, LO_FREQUENCY );
1199 sound->set_volume( 0.3 );
1200 globals->get_soundmgr()->add( sound, "adf-ident" );
1202 int offset = (int)(sg_random() * 30.0);
1203 adf_play_count = offset / 4;
1204 adf_last_time = globals->get_time_params()->get_cur_time() -
1206 // cout << "offset = " << offset << " play_count = "
1207 // << adf_play_count << " adf_last_time = "
1208 // << adf_last_time << " current time = "
1209 // << globals->get_time_params()->get_cur_time() << endl;
1212 // cout << "Found an adf station in range" << endl;
1213 // cout << " id = " << nav.get_ident() << endl;
1218 adf_trans_ident = "";
1219 #ifdef ENABLE_AUDIO_SUPPORT
1220 globals->get_soundmgr()->remove( "adf-ident" );
1222 last_adf_ident = "";
1223 // cout << "not picking up adf. :-(" << endl;
1228 // return the amount of heading needle deflection, returns a value
1229 // clamped to the range of ( -10 , 10 )
1230 double FGRadioStack::get_nav1_heading_needle_deflection() const {
1233 if ( nav1_inrange ) {
1234 r = nav1_heading - nav1_radial;
1235 // cout << "Radial = " << nav1_radial
1236 // << " Bearing = " << nav1_heading << endl;
1238 while ( r > 180.0 ) { r -= 360.0;}
1239 while ( r < -180.0 ) { r += 360.0;}
1240 if ( fabs(r) > 90.0 ) {
1241 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
1247 // According to Robin Peel, the ILS is 4x more sensitive than a vor
1248 if ( nav1_loc ) { r *= 4.0; }
1249 if ( r < -10.0 ) { r = -10.0; }
1250 if ( r > 10.0 ) { r = 10.0; }
1258 // return the amount of heading needle deflection, returns a value
1259 // clamped to the range of ( -10 , 10 )
1260 double FGRadioStack::get_nav2_heading_needle_deflection() const {
1263 if ( nav2_inrange ) {
1264 r = nav2_heading - nav2_radial;
1265 // cout << "Radial = " << nav2_radial
1266 // << " Bearing = " << nav2_heading << endl;
1268 while (r> 180.0) r-=360.0;
1269 while (r<-180.0) r+=360.0;
1270 if ( fabs(r) > 90.0 )
1271 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
1272 // According to Robin Peel, the ILS is 4x more sensitive than a vor
1273 if ( nav2_loc ) r *= 4.0;
1274 if ( r < -10.0 ) r = -10.0;
1275 if ( r > 10.0 ) r = 10.0;
1283 // return the amount of glide slope needle deflection (.i.e. the
1284 // number of degrees we are off the glide slope * 5.0
1285 double FGRadioStack::get_nav1_gs_needle_deflection() const {
1286 if ( nav1_inrange && nav1_has_gs ) {
1287 double x = nav1_gs_dist;
1288 double y = (fgGetDouble("/position/altitude-ft") - nav1_elev)
1290 double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
1291 return (nav1_target_gs - angle) * 5.0;
1298 // return the amount of glide slope needle deflection (.i.e. the
1299 // number of degrees we are off the glide slope * 5.0
1300 double FGRadioStack::get_nav2_gs_needle_deflection() const {
1301 if ( nav2_inrange && nav2_has_gs ) {
1302 double x = nav2_gs_dist;
1303 double y = (fgGetDouble("/position/altitude-ft") - nav2_elev)
1305 double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
1306 return (nav2_target_gs - angle) * 5.0;
1314 * Return true if the NAV1 TO flag should be active.
1317 FGRadioStack::get_nav1_to_flag () const
1320 double offset = fabs(nav1_heading - nav1_radial);
1324 return (offset <= 90.0 || offset >= 270.0);
1332 * Return true if the NAV1 FROM flag should be active.
1335 FGRadioStack::get_nav1_from_flag () const
1338 double offset = fabs(nav1_heading - nav1_radial);
1342 return (offset > 90.0 && offset < 270.0);
1350 * Return true if the NAV2 TO flag should be active.
1353 FGRadioStack::get_nav2_to_flag () const
1356 double offset = fabs(nav2_heading - nav2_radial);
1360 return (offset <= 90.0 || offset >= 270.0);
1368 * Return true if the NAV2 FROM flag should be active.
1371 FGRadioStack::get_nav2_from_flag () const
1374 double offset = fabs(nav2_heading - nav2_radial);
1378 return (offset > 90.0 && offset < 270.0);