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);
81 // Create a "serviceable" node with a default value of "true"
82 SGPropertyNode_ptr createServiceableProp(SGPropertyNode* aParent, const char* aName)
84 SGPropertyNode_ptr n = (aParent->getChild(aName, 0, true)->getChild("serviceable", 0, true));
85 simgear::props::Type typ = n->getType();
86 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED)) {
87 n->setBoolValue(true);
93 FGNavRadio::FGNavRadio(SGPropertyNode *node) :
94 lon_node(fgGetNode("/position/longitude-deg", true)),
95 lat_node(fgGetNode("/position/latitude-deg", true)),
96 alt_node(fgGetNode("/position/altitude-ft", true)),
103 last_xtrack_error(0.0),
105 _localizerWidth(5.0),
106 _name(node->getStringValue("name", "nav")),
107 _num(node->getIntValue("number", 0)),
108 _time_before_search_sec(-1.0),
111 SGPath path( globals->get_fg_root() );
113 term.append( "Navaids/range.term" );
115 low.append( "Navaids/range.low" );
117 high.append( "Navaids/range.high" );
119 term_tbl = new SGInterpTable( term.str() );
120 low_tbl = new SGInterpTable( low.str() );
121 high_tbl = new SGInterpTable( high.str() );
124 string branch("/instrumentation/" + _name);
125 _radio_node = fgGetNode(branch.c_str(), _num, true);
130 FGNavRadio::~FGNavRadio()
141 SGSoundMgr *smgr = globals->get_soundmgr();
142 _sgr = smgr->find("avionics", true);
143 _sgr->tie_to_listener();
147 SGPropertyNode* node = _radio_node.get();
149 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
152 is_valid_node = node->getChild("data-is-valid", 0, true);
153 power_btn_node = node->getChild("power-btn", 0, true);
154 power_btn_node->setBoolValue( true );
155 vol_btn_node = node->getChild("volume", 0, true);
156 ident_btn_node = node->getChild("ident", 0, true);
157 ident_btn_node->setBoolValue( true );
158 audio_btn_node = node->getChild("audio-btn", 0, true);
159 audio_btn_node->setBoolValue( true );
160 backcourse_node = node->getChild("back-course-btn", 0, true);
161 backcourse_node->setBoolValue( false );
163 nav_serviceable_node = node->getChild("serviceable", 0, true);
164 cdi_serviceable_node = createServiceableProp(node, "cdi");
165 gs_serviceable_node = createServiceableProp(node, "gs");
166 tofrom_serviceable_node = createServiceableProp(node, "to-from");
167 dme_serviceable_node = createServiceableProp(node, "dme");
169 falseCoursesEnabledNode =
170 fgGetNode("/sim/realism/false-radio-courses-enabled");
171 if (!falseCoursesEnabledNode) {
172 falseCoursesEnabledNode =
173 fgGetNode("/sim/realism/false-radio-courses-enabled", true);
174 falseCoursesEnabledNode->setBoolValue(true);
178 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
179 freq_node = subnode->getChild("selected-mhz", 0, true);
180 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
181 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
182 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
185 subnode = node->getChild("radials", 0, true);
186 sel_radial_node = subnode->getChild("selected-deg", 0, true);
187 radial_node = subnode->getChild("actual-deg", 0, true);
188 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
189 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
190 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
193 heading_node = node->getChild("heading-deg", 0, true);
194 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
195 to_flag_node = node->getChild("to-flag", 0, true);
196 from_flag_node = node->getChild("from-flag", 0, true);
197 inrange_node = node->getChild("in-range", 0, true);
198 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
199 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
200 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
201 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
202 cdi_xtrack_hdg_err_node
203 = node->getChild("crosstrack-heading-error-deg", 0, true);
204 has_gs_node = node->getChild("has-gs", 0, true);
205 loc_node = node->getChild("nav-loc", 0, true);
206 loc_dist_node = node->getChild("nav-distance", 0, true);
207 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
208 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
209 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
210 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
211 gs_rate_of_climb_fpm_node = node->getChild("gs-rate-of-climb-fpm", 0, true);
212 gs_dist_node = node->getChild("gs-distance", 0, true);
213 gs_inrange_node = node->getChild("gs-in-range", 0, true);
215 nav_id_node = node->getChild("nav-id", 0, true);
216 id_c1_node = node->getChild("nav-id_asc1", 0, true);
217 id_c2_node = node->getChild("nav-id_asc2", 0, true);
218 id_c3_node = node->getChild("nav-id_asc3", 0, true);
219 id_c4_node = node->getChild("nav-id_asc4", 0, true);
221 // gps slaving support
222 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
223 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
224 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
225 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
226 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
227 gps_course_node = fgGetNode("/instrumentation/gps/desired-course-deg", true);
228 gps_xtrack_error_nm_node = fgGetNode("/instrumentation/gps/wp/wp[1]/course-error-nm", true);
229 _magvarNode = fgGetNode("/environment/magnetic-variation-deg", true);
231 std::ostringstream temp;
232 temp << _name << "nav-ident" << _num;
233 nav_fx_name = temp.str();
234 temp << _name << "dme-ident" << _num;
235 dme_fx_name = temp.str();
241 tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
242 tie("operable", SGRawValueMethods<FGNavRadio, bool>(*this, &FGNavRadio::isOperable, NULL));
247 FGNavRadio::unbind ()
249 for (unsigned int t=0; t<_tiedNodes.size(); ++t) {
250 _tiedNodes[t]->untie();
256 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
257 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
258 double nominalRange )
260 if (nominalRange <= 0.0) {
261 nominalRange = FG_NAV_DEFAULT_RANGE;
264 // extend out actual usable range to be 1.3x the published safe range
265 const double usability_factor = 1.3;
267 // assumptions we model the standard service volume, plus
268 // ... rather than specifying a cylinder, we model a cone that
269 // contains the cylinder. Then we put an upside down cone on top
270 // to model diminishing returns at too-high altitudes.
272 // altitude difference
273 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
274 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
275 // << " station elev = " << stationElev << endl;
277 if ( nominalRange < 25.0 + SG_EPSILON ) {
278 // Standard Terminal Service Volume
279 return term_tbl->interpolate( alt ) * usability_factor;
280 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
281 // Standard Low Altitude Service Volume
282 // table is based on range of 40, scale to actual range
283 return low_tbl->interpolate( alt ) * nominalRange / 40.0
286 // Standard High Altitude Service Volume
287 // table is based on range of 130, scale to actual range
288 return high_tbl->interpolate( alt ) * nominalRange / 130.0
294 // model standard ILS service volumes as per AIM 1-1-9
295 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
296 double offsetDegrees, double distance )
298 // assumptions we model the standard service volume, plus
300 // altitude difference
301 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
302 // double offset = fabs( offsetDegrees );
304 // if ( offset < 10 ) {
305 // return FG_ILS_DEFAULT_RANGE;
306 // } else if ( offset < 35 ) {
307 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
308 // } else if ( offset < 45 ) {
309 // return (45 - offset);
310 // } else if ( offset > 170 ) {
311 // return FG_ILS_DEFAULT_RANGE;
312 // } else if ( offset > 145 ) {
313 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
314 // } else if ( offset > 135 ) {
315 // return (offset - 135);
319 return FG_LOC_DEFAULT_RANGE;
323 //////////////////////////////////////////////////////////////////////////
324 // Update the various nav values based on position and valid tuned in navs
325 //////////////////////////////////////////////////////////////////////////
327 FGNavRadio::update(double dt)
333 // Create "formatted" versions of the nav frequencies for
334 // instrument displays.
336 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
337 fmt_freq_node->setStringValue(tmp);
338 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
339 fmt_alt_freq_node->setStringValue(tmp);
341 if (power_btn_node->getBoolValue()
342 && (bus_power_node->getDoubleValue() > 1.0)
343 && nav_serviceable_node->getBoolValue() )
346 if (nav_slaved_to_gps_node->getBoolValue()) {
360 void FGNavRadio::clearOutputs()
362 inrange_node->setBoolValue( false );
363 cdi_deflection_node->setDoubleValue( 0.0 );
364 cdi_deflection_norm_node->setDoubleValue( 0.0 );
365 cdi_xtrack_error_node->setDoubleValue( 0.0 );
366 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
367 time_to_intercept->setDoubleValue( 0.0 );
368 gs_deflection_node->setDoubleValue( 0.0 );
369 gs_deflection_deg_node->setDoubleValue(0.0);
370 gs_deflection_norm_node->setDoubleValue(0.0);
371 gs_inrange_node->setBoolValue( false );
373 to_flag_node->setBoolValue( false );
374 from_flag_node->setBoolValue( false );
380 void FGNavRadio::updateReceiver(double dt)
382 // Do a nav station search only once a second to reduce
383 // unnecessary work. (Also, make sure to do this before caching
385 _time_before_search_sec -= dt;
386 if ( _time_before_search_sec < 0 ) {
391 _cdiDeflection = 0.0;
392 _cdiCrossTrackErrorM = 0.0;
393 _toFlag = _fromFlag = false;
394 _gsNeedleDeflection = 0.0;
395 _gsNeedleDeflectionNorm = 0.0;
396 inrange_node->setBoolValue(false);
400 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
401 lat_node->getDoubleValue(),
402 alt_node->getDoubleValue());
404 double nav_elev = _navaid->get_elev_ft();
405 SGVec3d aircraft = SGVec3d::fromGeod(pos);
406 double loc_dist = dist(aircraft, _navaid->cart());
407 loc_dist_node->setDoubleValue( loc_dist );
408 bool is_loc = loc_node->getBoolValue();
409 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
412 //////////////////////////////////////////////////////////
413 // compute forward and reverse wgs84 headings to localizer
414 //////////////////////////////////////////////////////////
416 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
417 heading_node->setDoubleValue(hdg);
418 double radial = az2 - twist;
419 double recip = radial + 180.0;
420 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
421 radial_node->setDoubleValue( radial );
422 recip_radial_node->setDoubleValue( recip );
424 //////////////////////////////////////////////////////////
425 // compute the target/selected radial in "true" heading
426 //////////////////////////////////////////////////////////
428 target_radial = sel_radial_node->getDoubleValue();
431 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
432 double trtrue = target_radial + twist;
433 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
434 target_radial_true_node->setDoubleValue( trtrue );
436 //////////////////////////////////////////////////////////
437 // adjust reception range for altitude
438 // FIXME: make sure we are using the navdata range now that
439 // it is valid in the data file
440 //////////////////////////////////////////////////////////
442 double offset = radial - target_radial;
443 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
445 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
446 loc_dist * SG_METER_TO_NM );
449 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
452 double effective_range_m = effective_range * SG_NM_TO_METER;
454 //////////////////////////////////////////////////////////
455 // compute signal quality
456 // 100% within effective_range
457 // decreases 1/x^2 further out
458 //////////////////////////////////////////////////////////
459 double last_signal_quality_norm = signal_quality_norm;
461 if ( loc_dist < effective_range_m ) {
462 signal_quality_norm = 1.0;
464 double range_exceed_norm = loc_dist/effective_range_m;
465 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
468 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
469 signal_quality_norm, dt );
471 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
472 bool inrange = signal_quality_norm > 0.2;
473 inrange_node->setBoolValue( inrange );
475 //////////////////////////////////////////////////////////
476 // compute to/from flag status
477 //////////////////////////////////////////////////////////
482 double offset = fabs(radial - target_radial);
483 _toFlag = (offset > 90.0 && offset < 270.0);
485 _fromFlag = !_toFlag;
487 _toFlag = _fromFlag = false;
491 double r = target_radial - radial;
492 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
495 if (falseCoursesEnabledNode->getBoolValue()) {
496 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
497 // zeros i.e. six courses: one front course, one back course, and four
498 // false courses. Three of the six are reverse sensing.
499 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
501 // no false courses, but we do need to create a back course
502 if (fabs(r) > 90.0) { // front course
503 _cdiDeflection = r - copysign(180.0, r);
505 _cdiDeflection = r; // back course
508 _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
509 } // of false courses disabled
511 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
512 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
514 if (backcourse_node->getBoolValue()) {
515 _cdiDeflection = -_cdiDeflection;
518 // handle the TO side of the VOR
519 if (fabs(r) > 90.0) {
520 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
523 } // of non-localiser case
525 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
526 _cdiDeflection *= signal_quality_norm;
528 // cross-track error (in metres)
529 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
531 updateGlideSlope(dt, aircraft, signal_quality_norm);
534 last_loc_dist = loc_dist;
537 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
539 _gsNeedleDeflection = 0.0;
540 if (!_gs || !inrange_node->getBoolValue()) {
541 gs_dist_node->setDoubleValue( 0.0 );
542 gs_inrange_node->setBoolValue(false);
543 _gsNeedleDeflection = 0.0;
544 _gsNeedleDeflectionNorm = 0.0;
548 double gsDist = dist(aircraft, _gsCart);
549 gs_dist_node->setDoubleValue(gsDist);
550 bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
551 gs_inrange_node->setBoolValue(gsInRange);
554 _gsNeedleDeflection = 0.0;
555 _gsNeedleDeflectionNorm = 0.0;
559 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
560 // The positive GS axis points along the runway in the landing direction,
561 // toward the far end, not toward the approach area, so we need a - sign here:
562 double dot_h = -dot(pos, _gsAxis);
563 double dot_v = dot(pos, _gsVertical);
564 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
565 double deflectionAngle = target_gs - angle;
567 if (falseCoursesEnabledNode->getBoolValue()) {
568 // Construct false glideslopes. The scale factor of 1.5
569 // in the sawtooth gives a period of 6 degrees.
570 // There will be zeros at 3, 6r, 9, 12r et cetera
571 // where "r" indicates reverse sensing.
572 // This is is consistent with conventional pilot lore
573 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
574 // but inconsistent with
575 // http://www.freepatentsonline.com/3757338.html
577 // It may be that some of each exist.
578 if (deflectionAngle < 0) {
579 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
581 // no false GS below the true GS
585 _gsNeedleDeflection = deflectionAngle * 5.0;
586 _gsNeedleDeflection *= signal_quality_norm;
588 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
589 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
591 //////////////////////////////////////////////////////////
592 // Calculate desired rate of climb for intercepting the GS
593 //////////////////////////////////////////////////////////
594 double gs_diff = target_gs - angle;
595 // convert desired vertical path angle into a climb rate
596 double des_angle = angle - 10 * gs_diff;
597 /* printf("target_gs=%.1f angle=%.1f gs_diff=%.1f des_angle=%.1f\n",
598 target_gs, angle, gs_diff, des_angle); */
600 // estimate horizontal speed towards ILS in meters per minute
601 double elapsedDistance = last_x - gsDist;
604 double new_vel = ( elapsedDistance / dt );
605 horiz_vel = 0.99 * horiz_vel + 0.01 * new_vel;
606 /* printf("vel=%.1f (dist=%.1f dt=%.2f)\n", horiz_vel, elapsedDistance, dt);*/
608 gs_rate_of_climb_node
609 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
610 * horiz_vel * SG_METER_TO_FEET );
611 gs_rate_of_climb_fpm_node
612 ->setDoubleValue( gs_rate_of_climb_node->getDoubleValue() * 60 );
615 void FGNavRadio::updateDME(const SGVec3d& aircraft)
617 if (!_dme || !dme_serviceable_node->getBoolValue()) {
622 double dme_distance = dist(aircraft, _dme->cart());
623 _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
626 void FGNavRadio::updateGPSSlaved()
628 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
630 _toFlag = gps_to_flag_node->getBoolValue();
631 _fromFlag = gps_from_flag_node->getBoolValue();
633 bool gpsValid = (_toFlag | _fromFlag);
634 inrange_node->setBoolValue(gpsValid);
636 signal_quality_norm_node->setDoubleValue(0.0);
637 _cdiDeflection = 0.0;
638 _cdiCrossTrackErrorM = 0.0;
639 _gsNeedleDeflection = 0.0;
643 // this is unfortunate, but panel instruments use this value to decide
644 // if the navradio output is valid.
645 signal_quality_norm_node->setDoubleValue(1.0);
647 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
648 // clmap to some range (+/- 10 degrees) as the regular deflection
649 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
651 _cdiCrossTrackErrorM = gps_xtrack_error_nm_node->getDoubleValue() * SG_NM_TO_METER;
652 _gsNeedleDeflection = 0.0; // FIXME, supply this
654 double trtrue = gps_course_node->getDoubleValue() + _magvarNode->getDoubleValue();
655 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
656 target_radial_true_node->setDoubleValue( trtrue );
659 void FGNavRadio::updateCDI(double dt)
661 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
662 bool inrange = inrange_node->getBoolValue();
664 if (tofrom_serviceable_node->getBoolValue()) {
665 to_flag_node->setBoolValue(_toFlag);
666 from_flag_node->setBoolValue(_fromFlag);
668 to_flag_node->setBoolValue(false);
669 from_flag_node->setBoolValue(false);
672 if (!cdi_serviceable) {
673 _cdiDeflection = 0.0;
674 _cdiCrossTrackErrorM = 0.0;
677 cdi_deflection_node->setDoubleValue(_cdiDeflection);
678 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
679 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
681 //////////////////////////////////////////////////////////
682 // compute an approximate ground track heading error
683 //////////////////////////////////////////////////////////
684 double hdg_error = 0.0;
685 if ( inrange && cdi_serviceable ) {
686 double vn = fgGetDouble( "/velocities/speed-north-fps" );
687 double ve = fgGetDouble( "/velocities/speed-east-fps" );
688 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
689 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
691 SGPropertyNode *true_hdg
692 = fgGetNode("/orientation/heading-deg", true);
693 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
695 // cout << "ground track = " << gnd_trk_true
696 // << " orientation = " << true_hdg->getDoubleValue() << endl;
698 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
700 //////////////////////////////////////////////////////////
701 // Calculate a suggested target heading to smoothly intercept
703 //////////////////////////////////////////////////////////
705 // Now that we have cross track heading adjustment built in,
706 // we shouldn't need to overdrive the heading angle within 8km
709 // The cdi deflection should be +/-10 for a full range of deflection
710 // so multiplying this by 3 gives us +/- 30 degrees heading
712 double adjustment = _cdiDeflection * 3.0;
713 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
715 // determine the target heading to fly to intercept the
716 // tgt_radial = target radial (true) + cdi offset adjustmest -
717 // xtrack heading error adjustment
719 double trtrue = target_radial_true_node->getDoubleValue();
720 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
721 // tuned to a localizer and backcourse mode activated
722 trtrue += 180.0; // reverse the target localizer heading
723 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
724 nta_hdg = trtrue - adjustment - hdg_error;
726 nta_hdg = trtrue + adjustment - hdg_error;
729 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
730 target_auto_hdg_node->setDoubleValue( nta_hdg );
732 //////////////////////////////////////////////////////////
733 // compute the time to intercept selected radial (based on
734 // current and last cross track errors and dt
735 //////////////////////////////////////////////////////////
737 if ( inrange && cdi_serviceable ) {
738 double cur_rate = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
739 xrate_ms = 0.99 * xrate_ms + 0.01 * cur_rate;
740 if ( fabs(xrate_ms) > 0.00001 ) {
741 t = _cdiCrossTrackErrorM / xrate_ms;
746 time_to_intercept->setDoubleValue( t );
748 if (!gs_serviceable_node->getBoolValue() ) {
749 _gsNeedleDeflection = 0.0;
750 _gsNeedleDeflectionNorm = 0.0;
752 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
753 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
754 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
756 last_xtrack_error = _cdiCrossTrackErrorM;
759 void FGNavRadio::updateAudio()
761 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
765 // play station ident via audio system if on + ident,
766 // otherwise turn it off
767 if (!power_btn_node->getBoolValue()
768 || !(bus_power_node->getDoubleValue() > 1.0)
769 || !ident_btn_node->getBoolValue()
770 || !audio_btn_node->getBoolValue() ) {
771 _sgr->stop( nav_fx_name );
772 _sgr->stop( dme_fx_name );
776 SGSoundSample *sound = _sgr->find( nav_fx_name );
777 double vol = vol_btn_node->getFloatValue();
778 SG_CLAMP_RANGE(vol, 0.0, 1.0);
780 if ( sound != NULL ) {
781 sound->set_volume( vol );
783 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
786 sound = _sgr->find( dme_fx_name );
787 if ( sound != NULL ) {
788 sound->set_volume( vol );
790 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
793 const int NUM_IDENT_SLOTS = 5;
794 const time_t SLOT_LENGTH = 5; // seconds
796 // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
797 // Each slot is 5 seconds long.
798 // Slots 0 is for DME
799 // the rest are for azimuth.
800 time_t now = globals->get_time_params()->get_cur_time();
801 if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
802 return; // wait longer
806 play_count = ++play_count % NUM_IDENT_SLOTS;
808 // Previous ident is out of time; if still playing, cut it off:
809 _sgr->stop( nav_fx_name );
810 _sgr->stop( dme_fx_name );
811 if (play_count == 0) { // the DME slot
812 if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
814 if (vol > 0.05) _sgr->play_once( dme_fx_name );
817 if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
818 if (vol > 0.05) _sgr->play_once(nav_fx_name);
823 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
825 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
830 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
833 // Update current nav/adf radio stations based on current postition
834 void FGNavRadio::search()
836 _time_before_search_sec = 1.0;
837 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
838 lat_node->getDoubleValue(), alt_node->getDoubleValue());
839 double freq = freq_node->getDoubleValue();
841 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
842 if (nav == _navaid) {
843 return; // found the same as last search, we're done
847 char identBuffer[5] = " ";
849 _dme = globals->get_dmelist()->findByFreq(freq, pos);
851 nav_id_node->setStringValue(nav->get_ident());
852 strncpy(identBuffer, nav->ident().c_str(), 5);
854 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
855 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
856 twist = nav->get_multiuse();
858 if (nav->type() == FGPositioned::VOR) {
859 target_radial = sel_radial_node->getDoubleValue();
861 has_gs_node->setBoolValue(false);
862 } else { // ILS or LOC
863 _gs = globals->get_gslist()->findByFreq(freq, pos);
864 has_gs_node->setBoolValue(_gs != NULL);
865 _localizerWidth = localizerWidth(nav);
867 effective_range = nav->get_range();
869 target_radial = nav->get_multiuse();
870 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
873 int tmp = (int)(_gs->get_multiuse() / 1000.0);
874 target_gs = (double)tmp / 100.0;
876 // until penaltyForNav goes away, we cannot assume we always pick
877 // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
878 // often end up picking the 'wrong' LOC, but the correct GS. To avoid
879 // breaking the basis computation, ensure we use the GS radial and not
880 // the (potentially reversed) LOC radial.
881 double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
882 SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
884 // GS axis unit tangent vector
885 // (along the runway)
886 _gsCart = _gs->cart();
887 _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
889 // GS baseline unit tangent vector
890 // (perpendicular to the runay along the ground)
891 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
892 _gsVertical = cross(baseline, _gsAxis);
893 } // of have glideslope
894 } // of found LOC or ILS
897 } else { // found nothing
900 nav_id_node->setStringValue("");
902 _sgr->remove( nav_fx_name );
903 _sgr->remove( dme_fx_name );
906 is_valid_node->setBoolValue(nav != NULL);
907 id_c1_node->setIntValue( (int)identBuffer[0] );
908 id_c2_node->setIntValue( (int)identBuffer[1] );
909 id_c3_node->setIntValue( (int)identBuffer[2] );
910 id_c4_node->setIntValue( (int)identBuffer[3] );
913 double FGNavRadio::localizerWidth(FGNavRecord* aLOC)
915 FGRunway* rwy = aLOC->runway();
918 SGVec3d thresholdCart(SGVec3d::fromGeod(rwy->threshold()));
919 double axisLength = dist(aLOC->cart(), thresholdCart);
920 double landingLength = dist(thresholdCart, SGVec3d::fromGeod(rwy->end()));
922 // Reference: http://dcaa.slv.dk:8000/icaodocs/
923 // ICAO standard width at threshold is 210 m = 689 feet = approx 700 feet.
924 // ICAO 3.1.1 half course = DDM = 0.0775
925 // ICAO 3.1.3.7.1 Sensitivity 0.00145 DDM/m at threshold
926 // implies peg-to-peg of 214 m ... we will stick with 210.
927 // ICAO 3.1.3.7.1 "Course sector angle shall not exceed 6 degrees."
929 // Very short runway: less than 1200 m (4000 ft) landing length:
930 if (landingLength < 1200.0) {
931 // ICAO fudges localizer sensitivity for very short runways.
932 // This produces a non-monotonic sensitivity-versus length relation.
933 axisLength += 1050.0;
936 // Example: very short: San Diego KMYF (Montgomery Field) ILS RWY 28R
937 // Example: short: Tom's River KMJX (Robert J. Miller) ILS RWY 6
938 // Example: very long: Denver KDEN (Denver) ILS RWY 16R
939 double raw_width = 210.0 / axisLength * SGD_RADIANS_TO_DEGREES;
940 return raw_width < 6.0? raw_width : 6.0;
943 void FGNavRadio::audioNavidChanged()
945 if (_sgr->exists(nav_fx_name)) {
946 _sgr->remove(nav_fx_name);
950 string trans_ident(_navaid->get_trans_ident());
951 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
952 sound->set_volume( 0.3 );
953 if (!_sgr->add( sound, nav_fx_name )) {
954 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
957 if ( _sgr->exists( dme_fx_name ) ) {
958 _sgr->remove( dme_fx_name );
961 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
962 sound->set_volume( 0.3 );
963 _sgr->add( sound, dme_fx_name );
965 int offset = (int)(sg_random() * 30.0);
966 play_count = offset / 4;
967 last_time = globals->get_time_params()->get_cur_time() - offset;
968 } catch (sg_io_exception& e) {
969 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());