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"
33 #include <simgear/sg_inlines.h>
34 #include <simgear/timing/sg_time.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>
40 #include <simgear/misc/strutils.hxx>
42 #include <Navaids/navrecord.hxx>
44 #include <Airports/runways.hxx>
45 #include <Navaids/navlist.hxx>
46 #include <Main/util.hxx>
51 // General-purpose sawtooth function. Graph looks like this:
54 // Odd symmetry, inversion symmetry about the origin.
55 // Unit slope at the origin.
56 // Max 1, min -1, period 4.
57 // Two zero-crossings per period, one with + slope, one with - slope.
58 // Useful for false localizer courses.
59 static double sawtooth(double xx)
61 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
64 // Calculate a unit vector in the horizontal tangent plane
65 // starting at the given "tail" of the vector and going off
66 // with the given heading.
67 static SGVec3d tangentVector(const SGGeod& tail, const SGVec3d& tail_xyz,
70 // The fudge factor here is presumably intended to improve
71 // numerical stability. I don't know if it is necessary.
72 // It gets divided out later.
75 double az2; // ignored
76 SGGeodesy::direct(tail, heading, fudge, head, az2);
77 head.setElevationM(tail.getElevationM());
78 SGVec3d head_xyz = SGVec3d::fromGeod(head);
79 return (head_xyz - tail_xyz) * (1.0/fudge);
82 // Create a "serviceable" node with a default value of "true"
83 SGPropertyNode_ptr createServiceableProp(SGPropertyNode* aParent, const char* aName)
85 SGPropertyNode_ptr n = (aParent->getChild(aName, 0, true)->getChild("serviceable", 0, true));
86 simgear::props::Type typ = n->getType();
87 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED)) {
88 n->setBoolValue(true);
94 FGNavRadio::FGNavRadio(SGPropertyNode *node) :
98 lon_node(fgGetNode("/position/longitude-deg", true)),
99 lat_node(fgGetNode("/position/latitude-deg", true)),
100 alt_node(fgGetNode("/position/altitude-ft", true)),
105 effective_range(0.0),
110 last_xtrack_error(0.0),
112 _localizerWidth(5.0),
113 _name(node->getStringValue("name", "nav")),
114 _num(node->getIntValue("number", 0)),
115 _time_before_search_sec(-1.0),
116 _gsCart(SGVec3d::zeros()),
117 _gsAxis(SGVec3d::zeros()),
118 _gsVertical(SGVec3d::zeros()),
123 _cdiCrossTrackErrorM(0.0),
124 _gsNeedleDeflection(0.0),
125 _gsNeedleDeflectionNorm(0.0),
128 SGPath path( globals->get_fg_root() );
130 term.append( "Navaids/range.term" );
132 low.append( "Navaids/range.low" );
134 high.append( "Navaids/range.high" );
136 term_tbl = new SGInterpTable( term.str() );
137 low_tbl = new SGInterpTable( low.str() );
138 high_tbl = new SGInterpTable( high.str() );
140 string branch("/instrumentation/" + _name);
141 _radio_node = fgGetNode(branch.c_str(), _num, true);
146 FGNavRadio::~FGNavRadio()
148 if (gps_course_node) {
149 gps_course_node->removeChangeListener(this);
152 if (nav_slaved_to_gps_node) {
153 nav_slaved_to_gps_node->removeChangeListener(this);
165 SGSoundMgr *smgr = globals->get_soundmgr();
166 _sgr = smgr->find("avionics", true);
167 _sgr->tie_to_listener();
171 SGPropertyNode* node = _radio_node.get();
173 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
176 is_valid_node = node->getChild("data-is-valid", 0, true);
177 power_btn_node = node->getChild("power-btn", 0, true);
178 power_btn_node->setBoolValue( true );
179 vol_btn_node = node->getChild("volume", 0, true);
180 ident_btn_node = node->getChild("ident", 0, true);
181 ident_btn_node->setBoolValue( true );
182 audio_btn_node = node->getChild("audio-btn", 0, true);
183 audio_btn_node->setBoolValue( true );
184 backcourse_node = node->getChild("back-course-btn", 0, true);
185 backcourse_node->setBoolValue( false );
187 nav_serviceable_node = node->getChild("serviceable", 0, true);
188 cdi_serviceable_node = createServiceableProp(node, "cdi");
189 gs_serviceable_node = createServiceableProp(node, "gs");
190 tofrom_serviceable_node = createServiceableProp(node, "to-from");
191 dme_serviceable_node = createServiceableProp(node, "dme");
193 falseCoursesEnabledNode =
194 fgGetNode("/sim/realism/false-radio-courses-enabled");
195 if (!falseCoursesEnabledNode) {
196 falseCoursesEnabledNode =
197 fgGetNode("/sim/realism/false-radio-courses-enabled", true);
198 falseCoursesEnabledNode->setBoolValue(true);
202 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
203 freq_node = subnode->getChild("selected-mhz", 0, true);
204 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
205 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
206 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
209 subnode = node->getChild("radials", 0, true);
210 sel_radial_node = subnode->getChild("selected-deg", 0, true);
211 radial_node = subnode->getChild("actual-deg", 0, true);
212 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
213 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
214 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
217 heading_node = node->getChild("heading-deg", 0, true);
218 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
219 to_flag_node = node->getChild("to-flag", 0, true);
220 from_flag_node = node->getChild("from-flag", 0, true);
221 inrange_node = node->getChild("in-range", 0, true);
222 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
223 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
224 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
225 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
226 cdi_xtrack_hdg_err_node
227 = node->getChild("crosstrack-heading-error-deg", 0, true);
228 has_gs_node = node->getChild("has-gs", 0, true);
229 loc_node = node->getChild("nav-loc", 0, true);
230 loc_dist_node = node->getChild("nav-distance", 0, true);
231 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
232 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
233 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
234 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
235 gs_rate_of_climb_fpm_node = node->getChild("gs-rate-of-climb-fpm", 0, true);
236 gs_dist_node = node->getChild("gs-distance", 0, true);
237 gs_inrange_node = node->getChild("gs-in-range", 0, true);
239 nav_id_node = node->getChild("nav-id", 0, true);
240 id_c1_node = node->getChild("nav-id_asc1", 0, true);
241 id_c2_node = node->getChild("nav-id_asc2", 0, true);
242 id_c3_node = node->getChild("nav-id_asc3", 0, true);
243 id_c4_node = node->getChild("nav-id_asc4", 0, true);
245 // gps slaving support
246 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
247 nav_slaved_to_gps_node->addChangeListener(this);
249 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
250 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
251 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
252 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
253 gps_course_node = fgGetNode("/instrumentation/gps/desired-course-deg", true);
254 gps_course_node->addChangeListener(this);
256 gps_xtrack_error_nm_node = fgGetNode("/instrumentation/gps/wp/wp[1]/course-error-nm", true);
257 _magvarNode = fgGetNode("/environment/magnetic-variation-deg", true);
259 std::ostringstream temp;
260 temp << _name << "nav-ident" << _num;
261 nav_fx_name = temp.str();
262 temp << _name << "dme-ident" << _num;
263 dme_fx_name = temp.str();
269 tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
270 tie("operable", SGRawValueMethods<FGNavRadio, bool>(*this, &FGNavRadio::isOperable, NULL));
275 FGNavRadio::unbind ()
277 for (unsigned int t=0; t<_tiedNodes.size(); ++t) {
278 _tiedNodes[t]->untie();
284 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
285 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
286 double nominalRange )
288 if (nominalRange <= 0.0) {
289 nominalRange = FG_NAV_DEFAULT_RANGE;
292 // extend out actual usable range to be 1.3x the published safe range
293 const double usability_factor = 1.3;
295 // assumptions we model the standard service volume, plus
296 // ... rather than specifying a cylinder, we model a cone that
297 // contains the cylinder. Then we put an upside down cone on top
298 // to model diminishing returns at too-high altitudes.
300 // altitude difference
301 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
302 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
303 // << " station elev = " << stationElev << endl;
305 if ( nominalRange < 25.0 + SG_EPSILON ) {
306 // Standard Terminal Service Volume
307 return term_tbl->interpolate( alt ) * usability_factor;
308 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
309 // Standard Low Altitude Service Volume
310 // table is based on range of 40, scale to actual range
311 return low_tbl->interpolate( alt ) * nominalRange / 40.0
314 // Standard High Altitude Service Volume
315 // table is based on range of 130, scale to actual range
316 return high_tbl->interpolate( alt ) * nominalRange / 130.0
322 // model standard ILS service volumes as per AIM 1-1-9
323 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
324 double offsetDegrees, double distance )
326 // assumptions we model the standard service volume, plus
328 // altitude difference
329 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
330 // double offset = fabs( offsetDegrees );
332 // if ( offset < 10 ) {
333 // return FG_ILS_DEFAULT_RANGE;
334 // } else if ( offset < 35 ) {
335 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
336 // } else if ( offset < 45 ) {
337 // return (45 - offset);
338 // } else if ( offset > 170 ) {
339 // return FG_ILS_DEFAULT_RANGE;
340 // } else if ( offset > 145 ) {
341 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
342 // } else if ( offset > 135 ) {
343 // return (offset - 135);
347 return FG_LOC_DEFAULT_RANGE;
351 //////////////////////////////////////////////////////////////////////////
352 // Update the various nav values based on position and valid tuned in navs
353 //////////////////////////////////////////////////////////////////////////
355 FGNavRadio::update(double dt)
361 // Create "formatted" versions of the nav frequencies for
362 // instrument displays.
364 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
365 fmt_freq_node->setStringValue(tmp);
366 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
367 fmt_alt_freq_node->setStringValue(tmp);
369 if (power_btn_node->getBoolValue()
370 && (bus_power_node->getDoubleValue() > 1.0)
371 && nav_serviceable_node->getBoolValue() )
383 void FGNavRadio::clearOutputs()
385 inrange_node->setBoolValue( false );
386 signal_quality_norm_node->setDoubleValue( 0.0 );
387 cdi_deflection_node->setDoubleValue( 0.0 );
388 cdi_deflection_norm_node->setDoubleValue( 0.0 );
389 cdi_xtrack_error_node->setDoubleValue( 0.0 );
390 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
391 time_to_intercept->setDoubleValue( 0.0 );
392 heading_node->setDoubleValue(0.0);
393 gs_deflection_node->setDoubleValue( 0.0 );
394 gs_deflection_deg_node->setDoubleValue(0.0);
395 gs_deflection_norm_node->setDoubleValue(0.0);
396 gs_inrange_node->setBoolValue( false );
397 loc_node->setBoolValue( false );
398 has_gs_node->setBoolValue(false);
400 to_flag_node->setBoolValue( false );
401 from_flag_node->setBoolValue( false );
402 is_valid_node->setBoolValue(false);
403 nav_id_node->setStringValue("");
410 void FGNavRadio::updateReceiver(double dt)
412 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
413 lat_node->getDoubleValue(),
414 alt_node->getDoubleValue());
415 SGVec3d aircraft = SGVec3d::fromGeod(pos);
418 // Do a nav station search only once a second to reduce
419 // unnecessary work. (Also, make sure to do this before caching
421 _time_before_search_sec -= dt;
422 if ( _time_before_search_sec < 0 ) {
428 loc_dist = dist(aircraft, _navaid->cart());
429 loc_dist_node->setDoubleValue( loc_dist );
433 if (nav_slaved_to_gps_node->getBoolValue()) {
434 // when slaved to GPS: only allow stuff above: tune NAV station
435 // upate DME. All other data driven by GPS only.
441 _cdiDeflection = 0.0;
442 _cdiCrossTrackErrorM = 0.0;
443 _toFlag = _fromFlag = false;
444 _gsNeedleDeflection = 0.0;
445 _gsNeedleDeflectionNorm = 0.0;
446 heading_node->setDoubleValue(0.0);
447 inrange_node->setBoolValue(false);
451 double nav_elev = _navaid->get_elev_ft();
453 bool is_loc = loc_node->getBoolValue();
454 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
457 //////////////////////////////////////////////////////////
458 // compute forward and reverse wgs84 headings to localizer
459 //////////////////////////////////////////////////////////
461 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
462 heading_node->setDoubleValue(hdg);
463 double radial = az2 - twist;
464 double recip = radial + 180.0;
465 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
466 radial_node->setDoubleValue( radial );
467 recip_radial_node->setDoubleValue( recip );
469 //////////////////////////////////////////////////////////
470 // compute the target/selected radial in "true" heading
471 //////////////////////////////////////////////////////////
473 target_radial = sel_radial_node->getDoubleValue();
476 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
477 double trtrue = target_radial + twist;
478 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
479 target_radial_true_node->setDoubleValue( trtrue );
481 //////////////////////////////////////////////////////////
482 // adjust reception range for altitude
483 // FIXME: make sure we are using the navdata range now that
484 // it is valid in the data file
485 //////////////////////////////////////////////////////////
487 double offset = radial - target_radial;
488 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
490 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
491 loc_dist * SG_METER_TO_NM );
494 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
497 double effective_range_m = effective_range * SG_NM_TO_METER;
499 //////////////////////////////////////////////////////////
500 // compute signal quality
501 // 100% within effective_range
502 // decreases 1/x^2 further out
503 //////////////////////////////////////////////////////////
504 double last_signal_quality_norm = signal_quality_norm;
506 if ( loc_dist < effective_range_m ) {
507 signal_quality_norm = 1.0;
509 double range_exceed_norm = loc_dist/effective_range_m;
510 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
513 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
514 signal_quality_norm, dt );
516 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
517 bool inrange = signal_quality_norm > 0.2;
518 inrange_node->setBoolValue( inrange );
520 //////////////////////////////////////////////////////////
521 // compute to/from flag status
522 //////////////////////////////////////////////////////////
527 double offset = fabs(radial - target_radial);
528 _toFlag = (offset > 90.0 && offset < 270.0);
530 _fromFlag = !_toFlag;
532 _toFlag = _fromFlag = false;
536 double r = target_radial - radial;
537 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
540 if (falseCoursesEnabledNode->getBoolValue()) {
541 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
542 // zeros i.e. six courses: one front course, one back course, and four
543 // false courses. Three of the six are reverse sensing.
544 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
546 // no false courses, but we do need to create a back course
547 if (fabs(r) > 90.0) { // front course
548 _cdiDeflection = r - copysign(180.0, r);
550 _cdiDeflection = r; // back course
553 _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
554 } // of false courses disabled
556 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
557 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
559 if (backcourse_node->getBoolValue()) {
560 _cdiDeflection = -_cdiDeflection;
563 // handle the TO side of the VOR
564 if (fabs(r) > 90.0) {
565 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
568 } // of non-localiser case
570 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
571 _cdiDeflection *= signal_quality_norm;
573 // cross-track error (in metres)
574 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
576 updateGlideSlope(dt, aircraft, signal_quality_norm);
579 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
581 _gsNeedleDeflection = 0.0;
582 if (!_gs || !inrange_node->getBoolValue()) {
583 gs_dist_node->setDoubleValue( 0.0 );
584 gs_inrange_node->setBoolValue(false);
585 _gsNeedleDeflection = 0.0;
586 _gsNeedleDeflectionNorm = 0.0;
590 double gsDist = dist(aircraft, _gsCart);
591 gs_dist_node->setDoubleValue(gsDist);
592 bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
593 gs_inrange_node->setBoolValue(gsInRange);
596 _gsNeedleDeflection = 0.0;
597 _gsNeedleDeflectionNorm = 0.0;
601 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
602 // The positive GS axis points along the runway in the landing direction,
603 // toward the far end, not toward the approach area, so we need a - sign here:
604 double dot_h = -dot(pos, _gsAxis);
605 double dot_v = dot(pos, _gsVertical);
606 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
607 double deflectionAngle = target_gs - angle;
609 if (falseCoursesEnabledNode->getBoolValue()) {
610 // Construct false glideslopes. The scale factor of 1.5
611 // in the sawtooth gives a period of 6 degrees.
612 // There will be zeros at 3, 6r, 9, 12r et cetera
613 // where "r" indicates reverse sensing.
614 // This is is consistent with conventional pilot lore
615 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
616 // but inconsistent with
617 // http://www.freepatentsonline.com/3757338.html
619 // It may be that some of each exist.
620 if (deflectionAngle < 0) {
621 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
623 // no false GS below the true GS
627 _gsNeedleDeflection = deflectionAngle * 5.0;
628 _gsNeedleDeflection *= signal_quality_norm;
630 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
631 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
633 //////////////////////////////////////////////////////////
634 // Calculate desired rate of climb for intercepting the GS
635 //////////////////////////////////////////////////////////
636 double gs_diff = target_gs - angle;
637 // convert desired vertical path angle into a climb rate
638 double des_angle = angle - 10 * gs_diff;
639 /* printf("target_gs=%.1f angle=%.1f gs_diff=%.1f des_angle=%.1f\n",
640 target_gs, angle, gs_diff, des_angle); */
642 // estimate horizontal speed towards ILS in meters per minute
643 double elapsedDistance = last_x - gsDist;
646 double new_vel = ( elapsedDistance / dt );
647 horiz_vel = 0.99 * horiz_vel + 0.01 * new_vel;
648 /* printf("vel=%.1f (dist=%.1f dt=%.2f)\n", horiz_vel, elapsedDistance, dt);*/
650 gs_rate_of_climb_node
651 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
652 * horiz_vel * SG_METER_TO_FEET );
653 gs_rate_of_climb_fpm_node
654 ->setDoubleValue( gs_rate_of_climb_node->getDoubleValue() * 60 );
657 void FGNavRadio::updateDME(const SGVec3d& aircraft)
659 if (!_dme || !dme_serviceable_node->getBoolValue()) {
664 double dme_distance = dist(aircraft, _dme->cart());
665 _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
668 void FGNavRadio::valueChanged (SGPropertyNode* prop)
670 if (prop == gps_course_node) {
671 if (!nav_slaved_to_gps_node->getBoolValue()) {
675 // GPS desired course has changed, sync up our selected-course
676 double v = prop->getDoubleValue();
677 if (v != sel_radial_node->getDoubleValue()) {
678 sel_radial_node->setDoubleValue(v);
680 } else if (prop == nav_slaved_to_gps_node) {
681 if (prop->getBoolValue()) {
682 // slaved-to-GPS activated, clear obsolete NAV outputs and sync up selected course
684 sel_radial_node->setDoubleValue(gps_course_node->getDoubleValue());
686 // slave-to-GPS enabled/disabled, resync NAV station (update all outputs)
688 _time_before_search_sec = 0;
692 void FGNavRadio::updateGPSSlaved()
694 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
696 _toFlag = gps_to_flag_node->getBoolValue();
697 _fromFlag = gps_from_flag_node->getBoolValue();
699 bool gpsValid = (_toFlag | _fromFlag);
700 inrange_node->setBoolValue(gpsValid);
702 signal_quality_norm_node->setDoubleValue(0.0);
703 _cdiDeflection = 0.0;
704 _cdiCrossTrackErrorM = 0.0;
705 _gsNeedleDeflection = 0.0;
706 _gsNeedleDeflectionNorm = 0.0;
710 // this is unfortunate, but panel instruments use this value to decide
711 // if the navradio output is valid.
712 signal_quality_norm_node->setDoubleValue(1.0);
714 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
715 // clmap to some range (+/- 10 degrees) as the regular deflection
716 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
718 _cdiCrossTrackErrorM = gps_xtrack_error_nm_node->getDoubleValue() * SG_NM_TO_METER;
719 _gsNeedleDeflection = 0.0; // FIXME, supply this
721 double trtrue = gps_course_node->getDoubleValue() + _magvarNode->getDoubleValue();
722 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
723 target_radial_true_node->setDoubleValue( trtrue );
726 void FGNavRadio::updateCDI(double dt)
728 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
729 bool inrange = inrange_node->getBoolValue();
731 if (tofrom_serviceable_node->getBoolValue()) {
732 to_flag_node->setBoolValue(_toFlag);
733 from_flag_node->setBoolValue(_fromFlag);
735 to_flag_node->setBoolValue(false);
736 from_flag_node->setBoolValue(false);
739 if (!cdi_serviceable) {
740 _cdiDeflection = 0.0;
741 _cdiCrossTrackErrorM = 0.0;
744 cdi_deflection_node->setDoubleValue(_cdiDeflection);
745 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
746 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
748 //////////////////////////////////////////////////////////
749 // compute an approximate ground track heading error
750 //////////////////////////////////////////////////////////
751 double hdg_error = 0.0;
752 if ( inrange && cdi_serviceable ) {
753 double vn = fgGetDouble( "/velocities/speed-north-fps" );
754 double ve = fgGetDouble( "/velocities/speed-east-fps" );
755 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
756 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
758 SGPropertyNode *true_hdg
759 = fgGetNode("/orientation/heading-deg", true);
760 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
762 // cout << "ground track = " << gnd_trk_true
763 // << " orientation = " << true_hdg->getDoubleValue() << endl;
765 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
767 //////////////////////////////////////////////////////////
768 // Calculate a suggested target heading to smoothly intercept
770 //////////////////////////////////////////////////////////
772 // Now that we have cross track heading adjustment built in,
773 // we shouldn't need to overdrive the heading angle within 8km
776 // The cdi deflection should be +/-10 for a full range of deflection
777 // so multiplying this by 3 gives us +/- 30 degrees heading
779 double adjustment = _cdiDeflection * 3.0;
780 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
782 // determine the target heading to fly to intercept the
783 // tgt_radial = target radial (true) + cdi offset adjustmest -
784 // xtrack heading error adjustment
786 double trtrue = target_radial_true_node->getDoubleValue();
787 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
788 // tuned to a localizer and backcourse mode activated
789 trtrue += 180.0; // reverse the target localizer heading
790 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
791 nta_hdg = trtrue - adjustment - hdg_error;
793 nta_hdg = trtrue + adjustment - hdg_error;
796 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
797 target_auto_hdg_node->setDoubleValue( nta_hdg );
799 //////////////////////////////////////////////////////////
800 // compute the time to intercept selected radial (based on
801 // current and last cross track errors and dt
802 //////////////////////////////////////////////////////////
804 if ( inrange && cdi_serviceable ) {
805 double cur_rate = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
806 xrate_ms = 0.99 * xrate_ms + 0.01 * cur_rate;
807 if ( fabs(xrate_ms) > 0.00001 ) {
808 t = _cdiCrossTrackErrorM / xrate_ms;
813 time_to_intercept->setDoubleValue( t );
815 if (!gs_serviceable_node->getBoolValue() ) {
816 _gsNeedleDeflection = 0.0;
817 _gsNeedleDeflectionNorm = 0.0;
819 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
820 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
821 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
823 last_xtrack_error = _cdiCrossTrackErrorM;
826 void FGNavRadio::updateAudio()
828 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
832 // play station ident via audio system if on + ident,
833 // otherwise turn it off
834 if (!power_btn_node->getBoolValue()
835 || !(bus_power_node->getDoubleValue() > 1.0)
836 || !ident_btn_node->getBoolValue()
837 || !audio_btn_node->getBoolValue() ) {
838 _sgr->stop( nav_fx_name );
839 _sgr->stop( dme_fx_name );
843 SGSoundSample *sound = _sgr->find( nav_fx_name );
844 double vol = vol_btn_node->getFloatValue();
845 SG_CLAMP_RANGE(vol, 0.0, 1.0);
847 if ( sound != NULL ) {
848 sound->set_volume( vol );
850 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
853 sound = _sgr->find( dme_fx_name );
854 if ( sound != NULL ) {
855 sound->set_volume( vol );
857 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
860 const int NUM_IDENT_SLOTS = 5;
861 const time_t SLOT_LENGTH = 5; // seconds
863 // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
864 // Each slot is 5 seconds long.
865 // Slots 0 is for DME
866 // the rest are for azimuth.
867 time_t now = globals->get_time_params()->get_cur_time();
868 if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
869 return; // wait longer
873 play_count = ++play_count % NUM_IDENT_SLOTS;
875 // Previous ident is out of time; if still playing, cut it off:
876 _sgr->stop( nav_fx_name );
877 _sgr->stop( dme_fx_name );
878 if (play_count == 0) { // the DME slot
879 if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
881 if (vol > 0.05) _sgr->play_once( dme_fx_name );
884 if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
885 if (vol > 0.05) _sgr->play_once(nav_fx_name);
890 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
892 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
897 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
900 // Update current nav/adf radio stations based on current postition
901 void FGNavRadio::search()
903 _time_before_search_sec = 1.0;
904 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
905 lat_node->getDoubleValue(), alt_node->getDoubleValue());
906 double freq = freq_node->getDoubleValue();
908 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
909 if (nav == _navaid) {
910 return; // found the same as last search, we're done
914 string identBuffer(4, ' ');
916 _dme = globals->get_dmelist()->findByFreq(freq, pos);
918 nav_id_node->setStringValue(nav->get_ident());
919 identBuffer = simgear::strutils::rpad( nav->ident(), 4, ' ' );
921 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
922 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
923 twist = nav->get_multiuse();
925 if (nav->type() == FGPositioned::VOR) {
926 target_radial = sel_radial_node->getDoubleValue();
928 has_gs_node->setBoolValue(false);
929 } else { // ILS or LOC
930 _gs = globals->get_gslist()->findByFreq(freq, pos);
931 has_gs_node->setBoolValue(_gs != NULL);
932 _localizerWidth = nav->localizerWidth();
934 effective_range = nav->get_range();
936 target_radial = nav->get_multiuse();
937 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
940 int tmp = (int)(_gs->get_multiuse() / 1000.0);
941 target_gs = (double)tmp / 100.0;
943 // until penaltyForNav goes away, we cannot assume we always pick
944 // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
945 // often end up picking the 'wrong' LOC, but the correct GS. To avoid
946 // breaking the basis computation, ensure we use the GS radial and not
947 // the (potentially reversed) LOC radial.
948 double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
949 SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
951 // GS axis unit tangent vector
952 // (along the runway)
953 _gsCart = _gs->cart();
954 _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
956 // GS baseline unit tangent vector
957 // (perpendicular to the runay along the ground)
958 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
959 _gsVertical = cross(baseline, _gsAxis);
960 } // of have glideslope
961 } // of found LOC or ILS
964 } else { // found nothing
967 nav_id_node->setStringValue("");
968 loc_node->setBoolValue(false);
969 has_gs_node->setBoolValue(false);
971 _sgr->remove( nav_fx_name );
972 _sgr->remove( dme_fx_name );
975 is_valid_node->setBoolValue(nav != NULL);
976 id_c1_node->setIntValue( (int)identBuffer[0] );
977 id_c2_node->setIntValue( (int)identBuffer[1] );
978 id_c3_node->setIntValue( (int)identBuffer[2] );
979 id_c4_node->setIntValue( (int)identBuffer[3] );
982 void FGNavRadio::audioNavidChanged()
984 if (_sgr->exists(nav_fx_name)) {
985 _sgr->remove(nav_fx_name);
989 string trans_ident(_navaid->get_trans_ident());
990 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
991 sound->set_volume( 0.3 );
992 if (!_sgr->add( sound, nav_fx_name )) {
993 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
996 if ( _sgr->exists( dme_fx_name ) ) {
997 _sgr->remove( dme_fx_name );
1000 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
1001 sound->set_volume( 0.3 );
1002 _sgr->add( sound, dme_fx_name );
1004 int offset = (int)(sg_random() * 30.0);
1005 play_count = offset / 4;
1006 last_time = globals->get_time_params()->get_cur_time() - offset;
1007 } catch (sg_io_exception& e) {
1008 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());