1 // navradio.cxx -- class to manage a nav radio instance
3 // Written by Curtis Olson, started April 2000.
5 // Copyright (C) 2000 - 2002 Curtis L. Olson - http://www.flightgear.org/~curt
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
28 #include "navradio.hxx"
32 #include <simgear/sg_inlines.h>
33 #include <simgear/timing/sg_time.hxx>
34 #include <simgear/math/vector.hxx>
35 #include <simgear/math/sg_random.h>
36 #include <simgear/misc/sg_path.hxx>
37 #include <simgear/math/sg_geodesy.hxx>
38 #include <simgear/structure/exception.hxx>
39 #include <simgear/math/interpolater.hxx>
41 #include <Navaids/navrecord.hxx>
43 #include <Airports/runways.hxx>
44 #include <Navaids/navlist.hxx>
45 #include <Main/util.hxx>
50 // General-purpose sawtooth function. Graph looks like this:
53 // Odd symmetry, inversion symmetry about the origin.
54 // Unit slope at the origin.
55 // Max 1, min -1, period 4.
56 // Two zero-crossings per period, one with + slope, one with - slope.
57 // Useful for false localizer courses.
58 static double sawtooth(double xx)
60 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
63 // Calculate a unit vector in the horizontal tangent plane
64 // starting at the given "tail" of the vector and going off
65 // with the given heading.
66 static SGVec3d tangentVector(const SGGeod& tail, const SGVec3d& tail_xyz,
69 // The fudge factor here is presumably intended to improve
70 // numerical stability. I don't know if it is necessary.
71 // It gets divided out later.
74 double az2; // ignored
75 SGGeodesy::direct(tail, heading, fudge, head, az2);
76 head.setElevationM(tail.getElevationM());
77 SGVec3d head_xyz = SGVec3d::fromGeod(head);
78 return (head_xyz - tail_xyz) * (1.0/fudge);
82 FGNavRadio::FGNavRadio(SGPropertyNode *node) :
83 lon_node(fgGetNode("/position/longitude-deg", true)),
84 lat_node(fgGetNode("/position/latitude-deg", true)),
85 alt_node(fgGetNode("/position/altitude-ft", true)),
90 sel_radial_node(NULL),
94 backcourse_node(NULL),
95 nav_serviceable_node(NULL),
96 cdi_serviceable_node(NULL),
97 gs_serviceable_node(NULL),
98 tofrom_serviceable_node(NULL),
100 fmt_alt_freq_node(NULL),
103 recip_radial_node(NULL),
104 target_radial_true_node(NULL),
105 target_auto_hdg_node(NULL),
106 time_to_intercept(NULL),
108 from_flag_node(NULL),
110 signal_quality_norm_node(NULL),
111 cdi_deflection_node(NULL),
112 cdi_deflection_norm_node(NULL),
113 cdi_xtrack_error_node(NULL),
114 cdi_xtrack_hdg_err_node(NULL),
118 gs_deflection_node(NULL),
119 gs_deflection_deg_node(NULL),
120 gs_deflection_norm_node(NULL),
121 gs_rate_of_climb_node(NULL),
128 nav_slaved_to_gps_node(NULL),
129 gps_cdi_deflection_node(NULL),
130 gps_to_flag_node(NULL),
131 gps_from_flag_node(NULL),
132 gps_has_gs_node(NULL),
139 last_xtrack_error(0.0),
140 _localizerWidth(5.0),
141 _name(node->getStringValue("name", "nav")),
142 _num(node->getIntValue("number", 0)),
143 _time_before_search_sec(-1.0)
145 SGPath path( globals->get_fg_root() );
147 term.append( "Navaids/range.term" );
149 low.append( "Navaids/range.low" );
151 high.append( "Navaids/range.high" );
153 term_tbl = new SGInterpTable( term.str() );
154 low_tbl = new SGInterpTable( low.str() );
155 high_tbl = new SGInterpTable( high.str() );
160 FGNavRadio::~FGNavRadio()
174 branch = "/instrumentation/" + _name;
176 SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
179 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
182 is_valid_node = node->getChild("data-is-valid", 0, true);
183 power_btn_node = node->getChild("power-btn", 0, true);
184 power_btn_node->setBoolValue( true );
185 vol_btn_node = node->getChild("volume", 0, true);
186 ident_btn_node = node->getChild("ident", 0, true);
187 ident_btn_node->setBoolValue( true );
188 audio_btn_node = node->getChild("audio-btn", 0, true);
189 audio_btn_node->setBoolValue( true );
190 backcourse_node = node->getChild("back-course-btn", 0, true);
191 backcourse_node->setBoolValue( false );
192 nav_serviceable_node = node->getChild("serviceable", 0, true);
193 cdi_serviceable_node = (node->getChild("cdi", 0, true))
194 ->getChild("serviceable", 0, true);
195 gs_serviceable_node = (node->getChild("gs", 0, true))
196 ->getChild("serviceable");
197 tofrom_serviceable_node = (node->getChild("to-from", 0, true))
198 ->getChild("serviceable", 0, true);
201 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
202 freq_node = subnode->getChild("selected-mhz", 0, true);
203 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
204 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
205 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
208 subnode = node->getChild("radials", 0, true);
209 sel_radial_node = subnode->getChild("selected-deg", 0, true);
210 radial_node = subnode->getChild("actual-deg", 0, true);
211 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
212 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
213 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
216 heading_node = node->getChild("heading-deg", 0, true);
217 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
218 to_flag_node = node->getChild("to-flag", 0, true);
219 from_flag_node = node->getChild("from-flag", 0, true);
220 inrange_node = node->getChild("in-range", 0, true);
221 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
222 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
223 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
224 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
225 cdi_xtrack_hdg_err_node
226 = node->getChild("crosstrack-heading-error-deg", 0, true);
227 has_gs_node = node->getChild("has-gs", 0, true);
228 loc_node = node->getChild("nav-loc", 0, true);
229 loc_dist_node = node->getChild("nav-distance", 0, true);
230 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
231 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
232 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
233 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
234 gs_dist_node = node->getChild("gs-distance", 0, true);
235 nav_id_node = node->getChild("nav-id", 0, true);
236 id_c1_node = node->getChild("nav-id_asc1", 0, true);
237 id_c2_node = node->getChild("nav-id_asc2", 0, true);
238 id_c3_node = node->getChild("nav-id_asc3", 0, true);
239 id_c4_node = node->getChild("nav-id_asc4", 0, true);
241 // gps slaving support
242 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
243 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
244 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
245 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
246 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
248 std::ostringstream temp;
249 temp << _name << "nav-ident" << _num;
250 nav_fx_name = temp.str();
251 temp << _name << "dme-ident" << _num;
252 dme_fx_name = temp.str();
258 std::ostringstream temp;
261 branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
266 FGNavRadio::unbind ()
268 std::ostringstream temp;
271 branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
275 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
276 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
277 double nominalRange )
279 // extend out actual usable range to be 1.3x the published safe range
280 const double usability_factor = 1.3;
282 // assumptions we model the standard service volume, plus
283 // ... rather than specifying a cylinder, we model a cone that
284 // contains the cylinder. Then we put an upside down cone on top
285 // to model diminishing returns at too-high altitudes.
287 // altitude difference
288 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
289 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
290 // << " station elev = " << stationElev << endl;
292 if ( nominalRange < 25.0 + SG_EPSILON ) {
293 // Standard Terminal Service Volume
294 return term_tbl->interpolate( alt ) * usability_factor;
295 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
296 // Standard Low Altitude Service Volume
297 // table is based on range of 40, scale to actual range
298 return low_tbl->interpolate( alt ) * nominalRange / 40.0
301 // Standard High Altitude Service Volume
302 // table is based on range of 130, scale to actual range
303 return high_tbl->interpolate( alt ) * nominalRange / 130.0
309 // model standard ILS service volumes as per AIM 1-1-9
310 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
311 double offsetDegrees, double distance )
313 // assumptions we model the standard service volume, plus
315 // altitude difference
316 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
317 // double offset = fabs( offsetDegrees );
319 // if ( offset < 10 ) {
320 // return FG_ILS_DEFAULT_RANGE;
321 // } else if ( offset < 35 ) {
322 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
323 // } else if ( offset < 45 ) {
324 // return (45 - offset);
325 // } else if ( offset > 170 ) {
326 // return FG_ILS_DEFAULT_RANGE;
327 // } else if ( offset > 145 ) {
328 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
329 // } else if ( offset > 135 ) {
330 // return (offset - 135);
334 return FG_LOC_DEFAULT_RANGE;
338 //////////////////////////////////////////////////////////////////////////
339 // Update the various nav values based on position and valid tuned in navs
340 //////////////////////////////////////////////////////////////////////////
342 FGNavRadio::update(double dt)
348 // Create "formatted" versions of the nav frequencies for
349 // instrument displays.
351 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
352 fmt_freq_node->setStringValue(tmp);
353 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
354 fmt_alt_freq_node->setStringValue(tmp);
356 if (power_btn_node->getBoolValue()
357 && (bus_power_node->getDoubleValue() > 1.0)
358 && nav_serviceable_node->getBoolValue() )
360 if (nav_slaved_to_gps_node->getBoolValue()) {
374 void FGNavRadio::clearOutputs()
376 inrange_node->setBoolValue( false );
377 cdi_deflection_node->setDoubleValue( 0.0 );
378 cdi_deflection_norm_node->setDoubleValue( 0.0 );
379 cdi_xtrack_error_node->setDoubleValue( 0.0 );
380 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
381 time_to_intercept->setDoubleValue( 0.0 );
382 gs_deflection_node->setDoubleValue( 0.0 );
383 gs_deflection_deg_node->setDoubleValue(0.0);
384 gs_deflection_norm_node->setDoubleValue(0.0);
386 to_flag_node->setBoolValue( false );
387 from_flag_node->setBoolValue( false );
390 void FGNavRadio::updateReceiver(double dt)
392 // Do a nav station search only once a second to reduce
393 // unnecessary work. (Also, make sure to do this before caching
395 _time_before_search_sec -= dt;
396 if ( _time_before_search_sec < 0 ) {
401 _cdiDeflection = 0.0;
402 _cdiCrossTrackErrorM = 0.0;
403 _toFlag = _fromFlag = false;
404 _gsNeedleDeflection = 0.0;
405 _gsNeedleDeflectionNorm = 0.0;
406 inrange_node->setBoolValue(false);
410 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
411 lat_node->getDoubleValue(),
412 alt_node->getDoubleValue());
414 double nav_elev = _navaid->get_elev_ft();
415 SGVec3d aircraft = SGVec3d::fromGeod(pos);
416 double loc_dist = dist(aircraft, _navaid->cart());
417 loc_dist_node->setDoubleValue( loc_dist );
418 bool is_loc = loc_node->getBoolValue();
419 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
422 //////////////////////////////////////////////////////////
423 // compute forward and reverse wgs84 headings to localizer
424 //////////////////////////////////////////////////////////
426 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
427 heading_node->setDoubleValue(hdg);
428 double radial = az2 - twist;
429 double recip = radial + 180.0;
430 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
431 radial_node->setDoubleValue( radial );
432 recip_radial_node->setDoubleValue( recip );
434 //////////////////////////////////////////////////////////
435 // compute the target/selected radial in "true" heading
436 //////////////////////////////////////////////////////////
438 target_radial = sel_radial_node->getDoubleValue();
441 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
442 double trtrue = target_radial + twist;
443 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
444 target_radial_true_node->setDoubleValue( trtrue );
446 //////////////////////////////////////////////////////////
447 // adjust reception range for altitude
448 // FIXME: make sure we are using the navdata range now that
449 // it is valid in the data file
450 //////////////////////////////////////////////////////////
452 double offset = radial - target_radial;
453 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
455 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
456 loc_dist * SG_METER_TO_NM );
459 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
462 double effective_range_m = effective_range * SG_NM_TO_METER;
464 //////////////////////////////////////////////////////////
465 // compute signal quality
466 // 100% within effective_range
467 // decreases 1/x^2 further out
468 //////////////////////////////////////////////////////////
469 double last_signal_quality_norm = signal_quality_norm;
471 if ( loc_dist < effective_range_m ) {
472 signal_quality_norm = 1.0;
474 double range_exceed_norm = loc_dist/effective_range_m;
475 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
478 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
479 signal_quality_norm, dt );
481 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
482 bool inrange = signal_quality_norm > 0.2;
483 inrange_node->setBoolValue( inrange );
485 //////////////////////////////////////////////////////////
486 // compute to/from flag status
487 //////////////////////////////////////////////////////////
492 double offset = fabs(radial - target_radial);
493 _toFlag = (offset > 90.0 && offset < 270.0);
495 _fromFlag = !_toFlag;
497 _toFlag = _fromFlag = false;
501 double r = target_radial - radial;
502 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
505 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
506 // zeros i.e. six courses: one front course, one back course, and four
507 // false courses. Three of the six are reverse sensing.
508 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
509 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
510 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
512 // handle the TO side of the VOR
513 if (fabs(r) > 90.0) {
514 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
517 } // of non-localiser case
519 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
520 _cdiDeflection *= signal_quality_norm;
522 // cross-track error (in metres)
523 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
525 updateGlideSlope(dt, aircraft, signal_quality_norm);
527 last_loc_dist = loc_dist;
530 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
532 _gsNeedleDeflection = 0.0;
533 if (!_gs || !inrange_node->getBoolValue()) {
534 gs_dist_node->setDoubleValue( 0.0 );
538 double gsDist = dist(aircraft, _gsCart);
539 gs_dist_node->setDoubleValue(gsDist);
540 if (gsDist > (_gs->get_range() * SG_NM_TO_METER)) {
544 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
545 // The positive GS axis points along the runway in the landing direction,
546 // toward the far end, not toward the approach area, so we need a - sign here:
547 double dot_h = -dot(pos, _gsAxis);
548 double dot_v = dot(pos, _gsVertical);
549 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
550 double deflectionAngle = target_gs - angle;
552 // Construct false glideslopes. The scale factor of 1.5
553 // in the sawtooth gives a period of 6 degrees.
554 // There will be zeros at 3, 6r, 9, 12r et cetera
555 // where "r" indicates reverse sensing.
556 // This is is consistent with conventional pilot lore
557 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
558 // but inconsistent with
559 // http://www.freepatentsonline.com/3757338.html
561 // It may be that some of each exist.
562 if (deflectionAngle < 0) {
563 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
565 // no false GS below the true GS
568 _gsNeedleDeflection = deflectionAngle * 5.0;
569 _gsNeedleDeflection *= signal_quality_norm;
571 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
572 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
574 //////////////////////////////////////////////////////////
575 // Calculate desired rate of climb for intercepting the GS
576 //////////////////////////////////////////////////////////
577 double gs_diff = target_gs - angle;
578 // convert desired vertical path angle into a climb rate
579 double des_angle = angle - 10 * gs_diff;
581 // estimate horizontal speed towards ILS in meters per minute
582 double elapsedDistance = last_x - gsDist;
585 double new_vel = ( elapsedDistance / dt );
586 horiz_vel = 0.75 * horiz_vel + 0.25 * new_vel;
588 gs_rate_of_climb_node
589 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
590 * horiz_vel * SG_METER_TO_FEET );
593 void FGNavRadio::updateGPSSlaved()
595 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
597 _toFlag = gps_to_flag_node->getBoolValue();
598 _fromFlag = gps_from_flag_node->getBoolValue();
600 inrange_node->setBoolValue(_toFlag | _fromFlag);
602 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
603 // clmap to some range (+/- 10 degrees) as the regular deflection
604 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
606 _cdiCrossTrackErrorM = 0.0; // FIXME, supply this
607 _gsNeedleDeflection = 0.0; // FIXME, supply this
610 void FGNavRadio::updateCDI(double dt)
612 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
613 bool inrange = inrange_node->getBoolValue();
615 if (tofrom_serviceable_node->getBoolValue()) {
616 to_flag_node->setBoolValue(_toFlag);
617 from_flag_node->setBoolValue(_fromFlag);
619 to_flag_node->setBoolValue(false);
620 from_flag_node->setBoolValue(false);
623 if (!cdi_serviceable) {
624 _cdiDeflection = 0.0;
625 _cdiCrossTrackErrorM = 0.0;
628 cdi_deflection_node->setDoubleValue(_cdiDeflection);
629 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
630 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
632 //////////////////////////////////////////////////////////
633 // compute an approximate ground track heading error
634 //////////////////////////////////////////////////////////
635 double hdg_error = 0.0;
636 if ( inrange && cdi_serviceable ) {
637 double vn = fgGetDouble( "/velocities/speed-north-fps" );
638 double ve = fgGetDouble( "/velocities/speed-east-fps" );
639 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
640 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
642 SGPropertyNode *true_hdg
643 = fgGetNode("/orientation/heading-deg", true);
644 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
646 // cout << "ground track = " << gnd_trk_true
647 // << " orientation = " << true_hdg->getDoubleValue() << endl;
649 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
651 //////////////////////////////////////////////////////////
652 // Calculate a suggested target heading to smoothly intercept
654 //////////////////////////////////////////////////////////
656 // Now that we have cross track heading adjustment built in,
657 // we shouldn't need to overdrive the heading angle within 8km
660 // The cdi deflection should be +/-10 for a full range of deflection
661 // so multiplying this by 3 gives us +/- 30 degrees heading
663 double adjustment = _cdiDeflection * 3.0;
664 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
666 // determine the target heading to fly to intercept the
667 // tgt_radial = target radial (true) + cdi offset adjustmest -
668 // xtrack heading error adjustment
670 double trtrue = target_radial_true_node->getDoubleValue();
671 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
672 // tuned to a localizer and backcourse mode activated
673 trtrue += 180.0; // reverse the target localizer heading
674 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
675 nta_hdg = trtrue - adjustment - hdg_error;
677 nta_hdg = trtrue + adjustment - hdg_error;
680 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
681 target_auto_hdg_node->setDoubleValue( nta_hdg );
683 //////////////////////////////////////////////////////////
684 // compute the time to intercept selected radial (based on
685 // current and last cross track errors and dt
686 //////////////////////////////////////////////////////////
688 if ( inrange && cdi_serviceable ) {
689 double xrate_ms = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
690 if ( fabs(xrate_ms) > 0.00001 ) {
691 t = _cdiCrossTrackErrorM / xrate_ms;
696 time_to_intercept->setDoubleValue( t );
698 if (!gs_serviceable_node->getBoolValue() ) {
699 _gsNeedleDeflection = 0.0;
700 _gsNeedleDeflectionNorm = 0.0;
702 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
703 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
704 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
706 last_xtrack_error = _cdiCrossTrackErrorM;
709 void FGNavRadio::updateAudio()
711 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
715 // play station ident via audio system if on + ident,
716 // otherwise turn it off
717 if (!power_btn_node->getBoolValue()
718 || !(bus_power_node->getDoubleValue() > 1.0)
719 || !ident_btn_node->getBoolValue()
720 || !audio_btn_node->getBoolValue() ) {
721 globals->get_soundmgr()->stop( nav_fx_name );
722 globals->get_soundmgr()->stop( dme_fx_name );
726 SGSoundSample *sound = globals->get_soundmgr()->find( nav_fx_name );
727 double vol = vol_btn_node->getDoubleValue();
728 SG_CLAMP_RANGE(vol, 0.0, 1.0);
730 if ( sound != NULL ) {
731 sound->set_volume( vol );
733 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
736 sound = globals->get_soundmgr()->find( dme_fx_name );
737 if ( sound != NULL ) {
738 sound->set_volume( vol );
740 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
743 if ( last_time < globals->get_time_params()->get_cur_time() - 30 ) {
744 last_time = globals->get_time_params()->get_cur_time();
748 if ( play_count < 4 ) {
750 if ( !globals->get_soundmgr()->is_playing(nav_fx_name) ) {
751 globals->get_soundmgr()->play_once( nav_fx_name );
754 } else if ( play_count < 5 && has_dme) {
756 if ( !globals->get_soundmgr()->is_playing(nav_fx_name) &&
757 !globals->get_soundmgr()->is_playing(dme_fx_name) ) {
758 globals->get_soundmgr()->play_once( dme_fx_name );
764 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
766 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
771 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
774 // Update current nav/adf radio stations based on current postition
775 void FGNavRadio::search()
777 _time_before_search_sec = 1.0;
778 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
779 lat_node->getDoubleValue(), alt_node->getDoubleValue());
780 double freq = freq_node->getDoubleValue();
782 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
783 if (nav == _navaid) {
784 return; // found the same as last search, we're done
788 char identBuffer[5] = " ";
790 FGNavRecord* dme = globals->get_dmelist()->findByFreq(freq, pos);
791 has_dme = (dme != NULL);
793 nav_id_node->setStringValue(nav->get_ident());
794 strncpy(identBuffer, nav->ident().c_str(), 5);
796 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
797 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
798 twist = nav->get_multiuse();
800 if (nav->type() == FGPositioned::VOR) {
801 target_radial = sel_radial_node->getDoubleValue();
803 } else { // ILS or LOC
804 _gs = globals->get_gslist()->findByFreq(freq, pos);
805 _localizerWidth = localizerWidth(nav);
806 has_gs_node->setBoolValue(_gs != NULL);
808 effective_range = nav->get_range();
810 target_radial = nav->get_multiuse();
811 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
814 int tmp = (int)(_gs->get_multiuse() / 1000.0);
815 target_gs = (double)tmp / 100.0;
817 // GS axis unit tangent vector
818 // (along the runway)
819 _gsCart = _gs->cart();
820 _gsAxis = tangentVector(_gs->geod(), _gsCart, target_radial);
822 // GS baseline unit tangent vector
823 // (perpendicular to the runay along the ground)
824 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, target_radial + 90.0);
825 _gsVertical = cross(baseline, _gsAxis);
826 } // of have glideslope
827 } // of found LOC or ILS
830 } else { // found nothing
832 nav_id_node->setStringValue("");
834 globals->get_soundmgr()->remove( nav_fx_name );
835 globals->get_soundmgr()->remove( dme_fx_name );
838 is_valid_node->setBoolValue(nav != NULL);
839 id_c1_node->setIntValue( (int)identBuffer[0] );
840 id_c2_node->setIntValue( (int)identBuffer[1] );
841 id_c3_node->setIntValue( (int)identBuffer[2] );
842 id_c4_node->setIntValue( (int)identBuffer[3] );
845 double FGNavRadio::localizerWidth(FGNavRecord* aLOC)
847 FGRunway* rwy = aLOC->runway();
850 SGVec3d thresholdCart(SGVec3d::fromGeod(rwy->threshold()));
851 double axisLength = dist(aLOC->cart(), thresholdCart);
852 double landingLength = dist(thresholdCart, SGVec3d::fromGeod(rwy->end()));
854 // Reference: http://dcaa.slv.dk:8000/icaodocs/
855 // ICAO standard width at threshold is 210 m = 689 feet = approx 700 feet.
856 // ICAO 3.1.1 half course = DDM = 0.0775
857 // ICAO 3.1.3.7.1 Sensitivity 0.00145 DDM/m at threshold
858 // implies peg-to-peg of 214 m ... we will stick with 210.
859 // ICAO 3.1.3.7.1 "Course sector angle shall not exceed 6 degrees."
861 // Very short runway: less than 1200 m (4000 ft) landing length:
862 if (landingLength < 1200.0) {
863 // ICAO fudges localizer sensitivity for very short runways.
864 // This produces a non-monotonic sensitivity-versus length relation.
865 axisLength += 1050.0;
868 // Example: very short: San Diego KMYF (Montgomery Field) ILS RWY 28R
869 // Example: short: Tom's River KMJX (Robert J. Miller) ILS RWY 6
870 // Example: very long: Denver KDEN (Denver) ILS RWY 16R
871 double raw_width = 210.0 / axisLength * SGD_RADIANS_TO_DEGREES;
872 return raw_width < 6.0? raw_width : 6.0;
875 void FGNavRadio::audioNavidChanged()
877 if ( globals->get_soundmgr()->exists(nav_fx_name)) {
878 globals->get_soundmgr()->remove(nav_fx_name);
882 string trans_ident(_navaid->get_trans_ident());
883 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
884 sound->set_volume( 0.3 );
885 if (!globals->get_soundmgr()->add( sound, nav_fx_name )) {
886 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
889 if ( globals->get_soundmgr()->exists( dme_fx_name ) ) {
890 globals->get_soundmgr()->remove( dme_fx_name );
893 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
894 sound->set_volume( 0.3 );
895 globals->get_soundmgr()->add( sound, dme_fx_name );
897 int offset = (int)(sg_random() * 30.0);
898 play_count = offset / 4;
899 last_time = globals->get_time_params()->get_cur_time() - offset;
900 } catch (sg_io_exception& e) {
901 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());