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) :
95 lon_node(fgGetNode("/position/longitude-deg", true)),
96 lat_node(fgGetNode("/position/latitude-deg", true)),
97 alt_node(fgGetNode("/position/altitude-ft", true)),
104 last_xtrack_error(0.0),
106 _localizerWidth(5.0),
107 _name(node->getStringValue("name", "nav")),
108 _num(node->getIntValue("number", 0)),
109 _time_before_search_sec(-1.0),
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() );
125 string branch("/instrumentation/" + _name);
126 _radio_node = fgGetNode(branch.c_str(), _num, true);
131 FGNavRadio::~FGNavRadio()
133 if (gps_course_node) {
134 gps_course_node->removeChangeListener(this);
137 if (nav_slaved_to_gps_node) {
138 nav_slaved_to_gps_node->removeChangeListener(this);
150 SGSoundMgr *smgr = globals->get_soundmgr();
151 _sgr = smgr->find("avionics", true);
152 _sgr->tie_to_listener();
156 SGPropertyNode* node = _radio_node.get();
158 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
161 is_valid_node = node->getChild("data-is-valid", 0, true);
162 power_btn_node = node->getChild("power-btn", 0, true);
163 power_btn_node->setBoolValue( true );
164 vol_btn_node = node->getChild("volume", 0, true);
165 ident_btn_node = node->getChild("ident", 0, true);
166 ident_btn_node->setBoolValue( true );
167 audio_btn_node = node->getChild("audio-btn", 0, true);
168 audio_btn_node->setBoolValue( true );
169 backcourse_node = node->getChild("back-course-btn", 0, true);
170 backcourse_node->setBoolValue( false );
172 nav_serviceable_node = node->getChild("serviceable", 0, true);
173 cdi_serviceable_node = createServiceableProp(node, "cdi");
174 gs_serviceable_node = createServiceableProp(node, "gs");
175 tofrom_serviceable_node = createServiceableProp(node, "to-from");
176 dme_serviceable_node = createServiceableProp(node, "dme");
178 falseCoursesEnabledNode =
179 fgGetNode("/sim/realism/false-radio-courses-enabled");
180 if (!falseCoursesEnabledNode) {
181 falseCoursesEnabledNode =
182 fgGetNode("/sim/realism/false-radio-courses-enabled", true);
183 falseCoursesEnabledNode->setBoolValue(true);
187 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
188 freq_node = subnode->getChild("selected-mhz", 0, true);
189 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
190 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
191 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
194 subnode = node->getChild("radials", 0, true);
195 sel_radial_node = subnode->getChild("selected-deg", 0, true);
196 radial_node = subnode->getChild("actual-deg", 0, true);
197 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
198 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
199 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
202 heading_node = node->getChild("heading-deg", 0, true);
203 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
204 to_flag_node = node->getChild("to-flag", 0, true);
205 from_flag_node = node->getChild("from-flag", 0, true);
206 inrange_node = node->getChild("in-range", 0, true);
207 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
208 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
209 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
210 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
211 cdi_xtrack_hdg_err_node
212 = node->getChild("crosstrack-heading-error-deg", 0, true);
213 has_gs_node = node->getChild("has-gs", 0, true);
214 loc_node = node->getChild("nav-loc", 0, true);
215 loc_dist_node = node->getChild("nav-distance", 0, true);
216 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
217 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
218 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
219 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
220 gs_rate_of_climb_fpm_node = node->getChild("gs-rate-of-climb-fpm", 0, true);
221 gs_dist_node = node->getChild("gs-distance", 0, true);
222 gs_inrange_node = node->getChild("gs-in-range", 0, true);
224 nav_id_node = node->getChild("nav-id", 0, true);
225 id_c1_node = node->getChild("nav-id_asc1", 0, true);
226 id_c2_node = node->getChild("nav-id_asc2", 0, true);
227 id_c3_node = node->getChild("nav-id_asc3", 0, true);
228 id_c4_node = node->getChild("nav-id_asc4", 0, true);
230 // gps slaving support
231 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
232 nav_slaved_to_gps_node->addChangeListener(this);
234 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
235 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
236 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
237 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
238 gps_course_node = fgGetNode("/instrumentation/gps/desired-course-deg", true);
239 gps_course_node->addChangeListener(this);
241 gps_xtrack_error_nm_node = fgGetNode("/instrumentation/gps/wp/wp[1]/course-error-nm", true);
242 _magvarNode = fgGetNode("/environment/magnetic-variation-deg", true);
244 std::ostringstream temp;
245 temp << _name << "nav-ident" << _num;
246 nav_fx_name = temp.str();
247 temp << _name << "dme-ident" << _num;
248 dme_fx_name = temp.str();
254 tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
255 tie("operable", SGRawValueMethods<FGNavRadio, bool>(*this, &FGNavRadio::isOperable, NULL));
260 FGNavRadio::unbind ()
262 for (unsigned int t=0; t<_tiedNodes.size(); ++t) {
263 _tiedNodes[t]->untie();
269 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
270 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
271 double nominalRange )
273 if (nominalRange <= 0.0) {
274 nominalRange = FG_NAV_DEFAULT_RANGE;
277 // extend out actual usable range to be 1.3x the published safe range
278 const double usability_factor = 1.3;
280 // assumptions we model the standard service volume, plus
281 // ... rather than specifying a cylinder, we model a cone that
282 // contains the cylinder. Then we put an upside down cone on top
283 // to model diminishing returns at too-high altitudes.
285 // altitude difference
286 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
287 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
288 // << " station elev = " << stationElev << endl;
290 if ( nominalRange < 25.0 + SG_EPSILON ) {
291 // Standard Terminal Service Volume
292 return term_tbl->interpolate( alt ) * usability_factor;
293 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
294 // Standard Low Altitude Service Volume
295 // table is based on range of 40, scale to actual range
296 return low_tbl->interpolate( alt ) * nominalRange / 40.0
299 // Standard High Altitude Service Volume
300 // table is based on range of 130, scale to actual range
301 return high_tbl->interpolate( alt ) * nominalRange / 130.0
307 // model standard ILS service volumes as per AIM 1-1-9
308 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
309 double offsetDegrees, double distance )
311 // assumptions we model the standard service volume, plus
313 // altitude difference
314 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
315 // double offset = fabs( offsetDegrees );
317 // if ( offset < 10 ) {
318 // return FG_ILS_DEFAULT_RANGE;
319 // } else if ( offset < 35 ) {
320 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
321 // } else if ( offset < 45 ) {
322 // return (45 - offset);
323 // } else if ( offset > 170 ) {
324 // return FG_ILS_DEFAULT_RANGE;
325 // } else if ( offset > 145 ) {
326 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
327 // } else if ( offset > 135 ) {
328 // return (offset - 135);
332 return FG_LOC_DEFAULT_RANGE;
336 //////////////////////////////////////////////////////////////////////////
337 // Update the various nav values based on position and valid tuned in navs
338 //////////////////////////////////////////////////////////////////////////
340 FGNavRadio::update(double dt)
346 // Create "formatted" versions of the nav frequencies for
347 // instrument displays.
349 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
350 fmt_freq_node->setStringValue(tmp);
351 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
352 fmt_alt_freq_node->setStringValue(tmp);
354 if (power_btn_node->getBoolValue()
355 && (bus_power_node->getDoubleValue() > 1.0)
356 && nav_serviceable_node->getBoolValue() )
359 if (nav_slaved_to_gps_node->getBoolValue()) {
373 void FGNavRadio::clearOutputs()
375 inrange_node->setBoolValue( false );
376 cdi_deflection_node->setDoubleValue( 0.0 );
377 cdi_deflection_norm_node->setDoubleValue( 0.0 );
378 cdi_xtrack_error_node->setDoubleValue( 0.0 );
379 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
380 time_to_intercept->setDoubleValue( 0.0 );
381 gs_deflection_node->setDoubleValue( 0.0 );
382 gs_deflection_deg_node->setDoubleValue(0.0);
383 gs_deflection_norm_node->setDoubleValue(0.0);
384 gs_inrange_node->setBoolValue( false );
385 loc_node->setBoolValue( false );
386 has_gs_node->setBoolValue(false);
388 to_flag_node->setBoolValue( false );
389 from_flag_node->setBoolValue( false );
395 void FGNavRadio::updateReceiver(double dt)
397 // Do a nav station search only once a second to reduce
398 // unnecessary work. (Also, make sure to do this before caching
400 _time_before_search_sec -= dt;
401 if ( _time_before_search_sec < 0 ) {
406 _cdiDeflection = 0.0;
407 _cdiCrossTrackErrorM = 0.0;
408 _toFlag = _fromFlag = false;
409 _gsNeedleDeflection = 0.0;
410 _gsNeedleDeflectionNorm = 0.0;
411 inrange_node->setBoolValue(false);
415 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
416 lat_node->getDoubleValue(),
417 alt_node->getDoubleValue());
419 double nav_elev = _navaid->get_elev_ft();
420 SGVec3d aircraft = SGVec3d::fromGeod(pos);
421 double loc_dist = dist(aircraft, _navaid->cart());
422 loc_dist_node->setDoubleValue( loc_dist );
423 bool is_loc = loc_node->getBoolValue();
424 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
427 //////////////////////////////////////////////////////////
428 // compute forward and reverse wgs84 headings to localizer
429 //////////////////////////////////////////////////////////
431 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
432 heading_node->setDoubleValue(hdg);
433 double radial = az2 - twist;
434 double recip = radial + 180.0;
435 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
436 radial_node->setDoubleValue( radial );
437 recip_radial_node->setDoubleValue( recip );
439 //////////////////////////////////////////////////////////
440 // compute the target/selected radial in "true" heading
441 //////////////////////////////////////////////////////////
443 target_radial = sel_radial_node->getDoubleValue();
446 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
447 double trtrue = target_radial + twist;
448 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
449 target_radial_true_node->setDoubleValue( trtrue );
451 //////////////////////////////////////////////////////////
452 // adjust reception range for altitude
453 // FIXME: make sure we are using the navdata range now that
454 // it is valid in the data file
455 //////////////////////////////////////////////////////////
457 double offset = radial - target_radial;
458 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
460 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
461 loc_dist * SG_METER_TO_NM );
464 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
467 double effective_range_m = effective_range * SG_NM_TO_METER;
469 //////////////////////////////////////////////////////////
470 // compute signal quality
471 // 100% within effective_range
472 // decreases 1/x^2 further out
473 //////////////////////////////////////////////////////////
474 double last_signal_quality_norm = signal_quality_norm;
476 if ( loc_dist < effective_range_m ) {
477 signal_quality_norm = 1.0;
479 double range_exceed_norm = loc_dist/effective_range_m;
480 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
483 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
484 signal_quality_norm, dt );
486 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
487 bool inrange = signal_quality_norm > 0.2;
488 inrange_node->setBoolValue( inrange );
490 //////////////////////////////////////////////////////////
491 // compute to/from flag status
492 //////////////////////////////////////////////////////////
497 double offset = fabs(radial - target_radial);
498 _toFlag = (offset > 90.0 && offset < 270.0);
500 _fromFlag = !_toFlag;
502 _toFlag = _fromFlag = false;
506 double r = target_radial - radial;
507 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
510 if (falseCoursesEnabledNode->getBoolValue()) {
511 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
512 // zeros i.e. six courses: one front course, one back course, and four
513 // false courses. Three of the six are reverse sensing.
514 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
516 // no false courses, but we do need to create a back course
517 if (fabs(r) > 90.0) { // front course
518 _cdiDeflection = r - copysign(180.0, r);
520 _cdiDeflection = r; // back course
523 _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
524 } // of false courses disabled
526 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
527 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
529 if (backcourse_node->getBoolValue()) {
530 _cdiDeflection = -_cdiDeflection;
533 // handle the TO side of the VOR
534 if (fabs(r) > 90.0) {
535 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
538 } // of non-localiser case
540 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
541 _cdiDeflection *= signal_quality_norm;
543 // cross-track error (in metres)
544 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
546 updateGlideSlope(dt, aircraft, signal_quality_norm);
549 last_loc_dist = loc_dist;
552 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
554 _gsNeedleDeflection = 0.0;
555 if (!_gs || !inrange_node->getBoolValue()) {
556 gs_dist_node->setDoubleValue( 0.0 );
557 gs_inrange_node->setBoolValue(false);
558 _gsNeedleDeflection = 0.0;
559 _gsNeedleDeflectionNorm = 0.0;
563 double gsDist = dist(aircraft, _gsCart);
564 gs_dist_node->setDoubleValue(gsDist);
565 bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
566 gs_inrange_node->setBoolValue(gsInRange);
569 _gsNeedleDeflection = 0.0;
570 _gsNeedleDeflectionNorm = 0.0;
574 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
575 // The positive GS axis points along the runway in the landing direction,
576 // toward the far end, not toward the approach area, so we need a - sign here:
577 double dot_h = -dot(pos, _gsAxis);
578 double dot_v = dot(pos, _gsVertical);
579 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
580 double deflectionAngle = target_gs - angle;
582 if (falseCoursesEnabledNode->getBoolValue()) {
583 // Construct false glideslopes. The scale factor of 1.5
584 // in the sawtooth gives a period of 6 degrees.
585 // There will be zeros at 3, 6r, 9, 12r et cetera
586 // where "r" indicates reverse sensing.
587 // This is is consistent with conventional pilot lore
588 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
589 // but inconsistent with
590 // http://www.freepatentsonline.com/3757338.html
592 // It may be that some of each exist.
593 if (deflectionAngle < 0) {
594 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
596 // no false GS below the true GS
600 _gsNeedleDeflection = deflectionAngle * 5.0;
601 _gsNeedleDeflection *= signal_quality_norm;
603 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
604 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
606 //////////////////////////////////////////////////////////
607 // Calculate desired rate of climb for intercepting the GS
608 //////////////////////////////////////////////////////////
609 double gs_diff = target_gs - angle;
610 // convert desired vertical path angle into a climb rate
611 double des_angle = angle - 10 * gs_diff;
612 /* printf("target_gs=%.1f angle=%.1f gs_diff=%.1f des_angle=%.1f\n",
613 target_gs, angle, gs_diff, des_angle); */
615 // estimate horizontal speed towards ILS in meters per minute
616 double elapsedDistance = last_x - gsDist;
619 double new_vel = ( elapsedDistance / dt );
620 horiz_vel = 0.99 * horiz_vel + 0.01 * new_vel;
621 /* printf("vel=%.1f (dist=%.1f dt=%.2f)\n", horiz_vel, elapsedDistance, dt);*/
623 gs_rate_of_climb_node
624 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
625 * horiz_vel * SG_METER_TO_FEET );
626 gs_rate_of_climb_fpm_node
627 ->setDoubleValue( gs_rate_of_climb_node->getDoubleValue() * 60 );
630 void FGNavRadio::updateDME(const SGVec3d& aircraft)
632 if (!_dme || !dme_serviceable_node->getBoolValue()) {
637 double dme_distance = dist(aircraft, _dme->cart());
638 _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
641 void FGNavRadio::valueChanged (SGPropertyNode* prop)
643 if (prop == gps_course_node) {
644 if (!nav_slaved_to_gps_node->getBoolValue()) {
648 // GPS desired course has changed, sync up our selected-course
649 double v = prop->getDoubleValue();
650 if (v != sel_radial_node->getDoubleValue()) {
651 sel_radial_node->setDoubleValue(v);
653 } else if (prop == nav_slaved_to_gps_node) {
654 if (prop->getBoolValue()) {
655 // slaved-to-GPS activated, sync up selected course
656 sel_radial_node->setDoubleValue(gps_course_node->getDoubleValue());
661 void FGNavRadio::updateGPSSlaved()
663 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
665 _toFlag = gps_to_flag_node->getBoolValue();
666 _fromFlag = gps_from_flag_node->getBoolValue();
668 bool gpsValid = (_toFlag | _fromFlag);
669 inrange_node->setBoolValue(gpsValid);
671 signal_quality_norm_node->setDoubleValue(0.0);
672 _cdiDeflection = 0.0;
673 _cdiCrossTrackErrorM = 0.0;
674 _gsNeedleDeflection = 0.0;
678 // this is unfortunate, but panel instruments use this value to decide
679 // if the navradio output is valid.
680 signal_quality_norm_node->setDoubleValue(1.0);
682 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
683 // clmap to some range (+/- 10 degrees) as the regular deflection
684 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
686 _cdiCrossTrackErrorM = gps_xtrack_error_nm_node->getDoubleValue() * SG_NM_TO_METER;
687 _gsNeedleDeflection = 0.0; // FIXME, supply this
689 double trtrue = gps_course_node->getDoubleValue() + _magvarNode->getDoubleValue();
690 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
691 target_radial_true_node->setDoubleValue( trtrue );
694 void FGNavRadio::updateCDI(double dt)
696 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
697 bool inrange = inrange_node->getBoolValue();
699 if (tofrom_serviceable_node->getBoolValue()) {
700 to_flag_node->setBoolValue(_toFlag);
701 from_flag_node->setBoolValue(_fromFlag);
703 to_flag_node->setBoolValue(false);
704 from_flag_node->setBoolValue(false);
707 if (!cdi_serviceable) {
708 _cdiDeflection = 0.0;
709 _cdiCrossTrackErrorM = 0.0;
712 cdi_deflection_node->setDoubleValue(_cdiDeflection);
713 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
714 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
716 //////////////////////////////////////////////////////////
717 // compute an approximate ground track heading error
718 //////////////////////////////////////////////////////////
719 double hdg_error = 0.0;
720 if ( inrange && cdi_serviceable ) {
721 double vn = fgGetDouble( "/velocities/speed-north-fps" );
722 double ve = fgGetDouble( "/velocities/speed-east-fps" );
723 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
724 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
726 SGPropertyNode *true_hdg
727 = fgGetNode("/orientation/heading-deg", true);
728 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
730 // cout << "ground track = " << gnd_trk_true
731 // << " orientation = " << true_hdg->getDoubleValue() << endl;
733 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
735 //////////////////////////////////////////////////////////
736 // Calculate a suggested target heading to smoothly intercept
738 //////////////////////////////////////////////////////////
740 // Now that we have cross track heading adjustment built in,
741 // we shouldn't need to overdrive the heading angle within 8km
744 // The cdi deflection should be +/-10 for a full range of deflection
745 // so multiplying this by 3 gives us +/- 30 degrees heading
747 double adjustment = _cdiDeflection * 3.0;
748 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
750 // determine the target heading to fly to intercept the
751 // tgt_radial = target radial (true) + cdi offset adjustmest -
752 // xtrack heading error adjustment
754 double trtrue = target_radial_true_node->getDoubleValue();
755 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
756 // tuned to a localizer and backcourse mode activated
757 trtrue += 180.0; // reverse the target localizer heading
758 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
759 nta_hdg = trtrue - adjustment - hdg_error;
761 nta_hdg = trtrue + adjustment - hdg_error;
764 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
765 target_auto_hdg_node->setDoubleValue( nta_hdg );
767 //////////////////////////////////////////////////////////
768 // compute the time to intercept selected radial (based on
769 // current and last cross track errors and dt
770 //////////////////////////////////////////////////////////
772 if ( inrange && cdi_serviceable ) {
773 double cur_rate = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
774 xrate_ms = 0.99 * xrate_ms + 0.01 * cur_rate;
775 if ( fabs(xrate_ms) > 0.00001 ) {
776 t = _cdiCrossTrackErrorM / xrate_ms;
781 time_to_intercept->setDoubleValue( t );
783 if (!gs_serviceable_node->getBoolValue() ) {
784 _gsNeedleDeflection = 0.0;
785 _gsNeedleDeflectionNorm = 0.0;
787 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
788 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
789 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
791 last_xtrack_error = _cdiCrossTrackErrorM;
794 void FGNavRadio::updateAudio()
796 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
800 // play station ident via audio system if on + ident,
801 // otherwise turn it off
802 if (!power_btn_node->getBoolValue()
803 || !(bus_power_node->getDoubleValue() > 1.0)
804 || !ident_btn_node->getBoolValue()
805 || !audio_btn_node->getBoolValue() ) {
806 _sgr->stop( nav_fx_name );
807 _sgr->stop( dme_fx_name );
811 SGSoundSample *sound = _sgr->find( nav_fx_name );
812 double vol = vol_btn_node->getFloatValue();
813 SG_CLAMP_RANGE(vol, 0.0, 1.0);
815 if ( sound != NULL ) {
816 sound->set_volume( vol );
818 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
821 sound = _sgr->find( dme_fx_name );
822 if ( sound != NULL ) {
823 sound->set_volume( vol );
825 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
828 const int NUM_IDENT_SLOTS = 5;
829 const time_t SLOT_LENGTH = 5; // seconds
831 // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
832 // Each slot is 5 seconds long.
833 // Slots 0 is for DME
834 // the rest are for azimuth.
835 time_t now = globals->get_time_params()->get_cur_time();
836 if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
837 return; // wait longer
841 play_count = ++play_count % NUM_IDENT_SLOTS;
843 // Previous ident is out of time; if still playing, cut it off:
844 _sgr->stop( nav_fx_name );
845 _sgr->stop( dme_fx_name );
846 if (play_count == 0) { // the DME slot
847 if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
849 if (vol > 0.05) _sgr->play_once( dme_fx_name );
852 if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
853 if (vol > 0.05) _sgr->play_once(nav_fx_name);
858 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
860 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
865 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
868 // Update current nav/adf radio stations based on current postition
869 void FGNavRadio::search()
871 _time_before_search_sec = 1.0;
872 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
873 lat_node->getDoubleValue(), alt_node->getDoubleValue());
874 double freq = freq_node->getDoubleValue();
876 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
877 if (nav == _navaid) {
878 return; // found the same as last search, we're done
882 string identBuffer(4, ' ');
884 _dme = globals->get_dmelist()->findByFreq(freq, pos);
886 nav_id_node->setStringValue(nav->get_ident());
887 identBuffer = simgear::strutils::rpad( nav->ident(), 4, ' ' );
889 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
890 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
891 twist = nav->get_multiuse();
893 if (nav->type() == FGPositioned::VOR) {
894 target_radial = sel_radial_node->getDoubleValue();
896 has_gs_node->setBoolValue(false);
897 } else { // ILS or LOC
898 _gs = globals->get_gslist()->findByFreq(freq, pos);
899 has_gs_node->setBoolValue(_gs != NULL);
900 _localizerWidth = nav->localizerWidth();
902 effective_range = nav->get_range();
904 target_radial = nav->get_multiuse();
905 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
908 int tmp = (int)(_gs->get_multiuse() / 1000.0);
909 target_gs = (double)tmp / 100.0;
911 // until penaltyForNav goes away, we cannot assume we always pick
912 // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
913 // often end up picking the 'wrong' LOC, but the correct GS. To avoid
914 // breaking the basis computation, ensure we use the GS radial and not
915 // the (potentially reversed) LOC radial.
916 double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
917 SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
919 // GS axis unit tangent vector
920 // (along the runway)
921 _gsCart = _gs->cart();
922 _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
924 // GS baseline unit tangent vector
925 // (perpendicular to the runay along the ground)
926 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
927 _gsVertical = cross(baseline, _gsAxis);
928 } // of have glideslope
929 } // of found LOC or ILS
932 } else { // found nothing
935 nav_id_node->setStringValue("");
936 loc_node->setBoolValue(false);
937 has_gs_node->setBoolValue(false);
939 _sgr->remove( nav_fx_name );
940 _sgr->remove( dme_fx_name );
943 is_valid_node->setBoolValue(nav != NULL);
944 id_c1_node->setIntValue( (int)identBuffer[0] );
945 id_c2_node->setIntValue( (int)identBuffer[1] );
946 id_c3_node->setIntValue( (int)identBuffer[2] );
947 id_c4_node->setIntValue( (int)identBuffer[3] );
950 void FGNavRadio::audioNavidChanged()
952 if (_sgr->exists(nav_fx_name)) {
953 _sgr->remove(nav_fx_name);
957 string trans_ident(_navaid->get_trans_ident());
958 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
959 sound->set_volume( 0.3 );
960 if (!_sgr->add( sound, nav_fx_name )) {
961 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
964 if ( _sgr->exists( dme_fx_name ) ) {
965 _sgr->remove( dme_fx_name );
968 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
969 sound->set_volume( 0.3 );
970 _sgr->add( sound, dme_fx_name );
972 int offset = (int)(sg_random() * 30.0);
973 play_count = offset / 4;
974 last_time = globals->get_time_params()->get_cur_time() - offset;
975 } catch (sg_io_exception& e) {
976 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());