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/sg_random.h>
35 #include <simgear/misc/sg_path.hxx>
36 #include <simgear/math/sg_geodesy.hxx>
37 #include <simgear/structure/exception.hxx>
38 #include <simgear/math/interpolater.hxx>
40 #include <Navaids/navrecord.hxx>
42 #include <Airports/runways.hxx>
43 #include <Navaids/navlist.hxx>
44 #include <Main/util.hxx>
49 // General-purpose sawtooth function. Graph looks like this:
52 // Odd symmetry, inversion symmetry about the origin.
53 // Unit slope at the origin.
54 // Max 1, min -1, period 4.
55 // Two zero-crossings per period, one with + slope, one with - slope.
56 // Useful for false localizer courses.
57 static double sawtooth(double xx)
59 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
62 // Calculate a unit vector in the horizontal tangent plane
63 // starting at the given "tail" of the vector and going off
64 // with the given heading.
65 static SGVec3d tangentVector(const SGGeod& tail, const SGVec3d& tail_xyz,
68 // The fudge factor here is presumably intended to improve
69 // numerical stability. I don't know if it is necessary.
70 // It gets divided out later.
73 double az2; // ignored
74 SGGeodesy::direct(tail, heading, fudge, head, az2);
75 head.setElevationM(tail.getElevationM());
76 SGVec3d head_xyz = SGVec3d::fromGeod(head);
77 return (head_xyz - tail_xyz) * (1.0/fudge);
80 // Create a "serviceable" node with a default value of "true"
81 SGPropertyNode_ptr createServiceableProp(SGPropertyNode* aParent, const char* aName)
83 SGPropertyNode_ptr n = (aParent->getChild(aName, 0, true)->getChild("serviceable", 0, true));
84 simgear::props::Type typ = n->getType();
85 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED)) {
86 n->setBoolValue(true);
92 FGNavRadio::FGNavRadio(SGPropertyNode *node) :
93 lon_node(fgGetNode("/position/longitude-deg", true)),
94 lat_node(fgGetNode("/position/latitude-deg", true)),
95 alt_node(fgGetNode("/position/altitude-ft", true)),
102 last_xtrack_error(0.0),
104 _localizerWidth(5.0),
105 _name(node->getStringValue("name", "nav")),
106 _num(node->getIntValue("number", 0)),
107 _time_before_search_sec(-1.0),
110 SGPath path( globals->get_fg_root() );
112 term.append( "Navaids/range.term" );
114 low.append( "Navaids/range.low" );
116 high.append( "Navaids/range.high" );
118 term_tbl = new SGInterpTable( term.str() );
119 low_tbl = new SGInterpTable( low.str() );
120 high_tbl = new SGInterpTable( high.str() );
123 string branch("/instrumentation/" + _name);
124 _radio_node = fgGetNode(branch.c_str(), _num, true);
129 FGNavRadio::~FGNavRadio()
131 if (gps_course_node) {
132 gps_course_node->removeChangeListener(this);
135 if (nav_slaved_to_gps_node) {
136 nav_slaved_to_gps_node->removeChangeListener(this);
148 SGSoundMgr *smgr = globals->get_soundmgr();
149 _sgr = smgr->find("avionics", true);
150 _sgr->tie_to_listener();
154 SGPropertyNode* node = _radio_node.get();
156 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
159 is_valid_node = node->getChild("data-is-valid", 0, true);
160 power_btn_node = node->getChild("power-btn", 0, true);
161 power_btn_node->setBoolValue( true );
162 vol_btn_node = node->getChild("volume", 0, true);
163 ident_btn_node = node->getChild("ident", 0, true);
164 ident_btn_node->setBoolValue( true );
165 audio_btn_node = node->getChild("audio-btn", 0, true);
166 audio_btn_node->setBoolValue( true );
167 backcourse_node = node->getChild("back-course-btn", 0, true);
168 backcourse_node->setBoolValue( false );
170 nav_serviceable_node = node->getChild("serviceable", 0, true);
171 cdi_serviceable_node = createServiceableProp(node, "cdi");
172 gs_serviceable_node = createServiceableProp(node, "gs");
173 tofrom_serviceable_node = createServiceableProp(node, "to-from");
174 dme_serviceable_node = createServiceableProp(node, "dme");
176 falseCoursesEnabledNode =
177 fgGetNode("/sim/realism/false-radio-courses-enabled");
178 if (!falseCoursesEnabledNode) {
179 falseCoursesEnabledNode =
180 fgGetNode("/sim/realism/false-radio-courses-enabled", true);
181 falseCoursesEnabledNode->setBoolValue(true);
185 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
186 freq_node = subnode->getChild("selected-mhz", 0, true);
187 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
188 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
189 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
192 subnode = node->getChild("radials", 0, true);
193 sel_radial_node = subnode->getChild("selected-deg", 0, true);
194 radial_node = subnode->getChild("actual-deg", 0, true);
195 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
196 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
197 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
200 heading_node = node->getChild("heading-deg", 0, true);
201 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
202 to_flag_node = node->getChild("to-flag", 0, true);
203 from_flag_node = node->getChild("from-flag", 0, true);
204 inrange_node = node->getChild("in-range", 0, true);
205 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
206 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
207 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
208 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
209 cdi_xtrack_hdg_err_node
210 = node->getChild("crosstrack-heading-error-deg", 0, true);
211 has_gs_node = node->getChild("has-gs", 0, true);
212 loc_node = node->getChild("nav-loc", 0, true);
213 loc_dist_node = node->getChild("nav-distance", 0, true);
214 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
215 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
216 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
217 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
218 gs_rate_of_climb_fpm_node = node->getChild("gs-rate-of-climb-fpm", 0, true);
219 gs_dist_node = node->getChild("gs-distance", 0, true);
220 gs_inrange_node = node->getChild("gs-in-range", 0, true);
222 nav_id_node = node->getChild("nav-id", 0, true);
223 id_c1_node = node->getChild("nav-id_asc1", 0, true);
224 id_c2_node = node->getChild("nav-id_asc2", 0, true);
225 id_c3_node = node->getChild("nav-id_asc3", 0, true);
226 id_c4_node = node->getChild("nav-id_asc4", 0, true);
228 // gps slaving support
229 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
230 nav_slaved_to_gps_node->addChangeListener(this);
232 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
233 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
234 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
235 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
236 gps_course_node = fgGetNode("/instrumentation/gps/desired-course-deg", true);
237 gps_course_node->addChangeListener(this);
239 gps_xtrack_error_nm_node = fgGetNode("/instrumentation/gps/wp/wp[1]/course-error-nm", true);
240 _magvarNode = fgGetNode("/environment/magnetic-variation-deg", true);
242 std::ostringstream temp;
243 temp << _name << "nav-ident" << _num;
244 nav_fx_name = temp.str();
245 temp << _name << "dme-ident" << _num;
246 dme_fx_name = temp.str();
252 tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
253 tie("operable", SGRawValueMethods<FGNavRadio, bool>(*this, &FGNavRadio::isOperable, NULL));
258 FGNavRadio::unbind ()
260 for (unsigned int t=0; t<_tiedNodes.size(); ++t) {
261 _tiedNodes[t]->untie();
267 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
268 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
269 double nominalRange )
271 if (nominalRange <= 0.0) {
272 nominalRange = FG_NAV_DEFAULT_RANGE;
275 // extend out actual usable range to be 1.3x the published safe range
276 const double usability_factor = 1.3;
278 // assumptions we model the standard service volume, plus
279 // ... rather than specifying a cylinder, we model a cone that
280 // contains the cylinder. Then we put an upside down cone on top
281 // to model diminishing returns at too-high altitudes.
283 // altitude difference
284 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
285 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
286 // << " station elev = " << stationElev << endl;
288 if ( nominalRange < 25.0 + SG_EPSILON ) {
289 // Standard Terminal Service Volume
290 return term_tbl->interpolate( alt ) * usability_factor;
291 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
292 // Standard Low Altitude Service Volume
293 // table is based on range of 40, scale to actual range
294 return low_tbl->interpolate( alt ) * nominalRange / 40.0
297 // Standard High Altitude Service Volume
298 // table is based on range of 130, scale to actual range
299 return high_tbl->interpolate( alt ) * nominalRange / 130.0
305 // model standard ILS service volumes as per AIM 1-1-9
306 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
307 double offsetDegrees, double distance )
309 // assumptions we model the standard service volume, plus
311 // altitude difference
312 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
313 // double offset = fabs( offsetDegrees );
315 // if ( offset < 10 ) {
316 // return FG_ILS_DEFAULT_RANGE;
317 // } else if ( offset < 35 ) {
318 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
319 // } else if ( offset < 45 ) {
320 // return (45 - offset);
321 // } else if ( offset > 170 ) {
322 // return FG_ILS_DEFAULT_RANGE;
323 // } else if ( offset > 145 ) {
324 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
325 // } else if ( offset > 135 ) {
326 // return (offset - 135);
330 return FG_LOC_DEFAULT_RANGE;
334 //////////////////////////////////////////////////////////////////////////
335 // Update the various nav values based on position and valid tuned in navs
336 //////////////////////////////////////////////////////////////////////////
338 FGNavRadio::update(double dt)
344 // Create "formatted" versions of the nav frequencies for
345 // instrument displays.
347 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
348 fmt_freq_node->setStringValue(tmp);
349 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
350 fmt_alt_freq_node->setStringValue(tmp);
352 if (power_btn_node->getBoolValue()
353 && (bus_power_node->getDoubleValue() > 1.0)
354 && nav_serviceable_node->getBoolValue() )
357 if (nav_slaved_to_gps_node->getBoolValue()) {
371 void FGNavRadio::clearOutputs()
373 inrange_node->setBoolValue( false );
374 cdi_deflection_node->setDoubleValue( 0.0 );
375 cdi_deflection_norm_node->setDoubleValue( 0.0 );
376 cdi_xtrack_error_node->setDoubleValue( 0.0 );
377 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
378 time_to_intercept->setDoubleValue( 0.0 );
379 gs_deflection_node->setDoubleValue( 0.0 );
380 gs_deflection_deg_node->setDoubleValue(0.0);
381 gs_deflection_norm_node->setDoubleValue(0.0);
382 gs_inrange_node->setBoolValue( false );
383 loc_node->setBoolValue( false );
384 has_gs_node->setBoolValue(false);
386 to_flag_node->setBoolValue( false );
387 from_flag_node->setBoolValue( false );
393 void FGNavRadio::updateReceiver(double dt)
395 // Do a nav station search only once a second to reduce
396 // unnecessary work. (Also, make sure to do this before caching
398 _time_before_search_sec -= dt;
399 if ( _time_before_search_sec < 0 ) {
404 _cdiDeflection = 0.0;
405 _cdiCrossTrackErrorM = 0.0;
406 _toFlag = _fromFlag = false;
407 _gsNeedleDeflection = 0.0;
408 _gsNeedleDeflectionNorm = 0.0;
409 inrange_node->setBoolValue(false);
413 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
414 lat_node->getDoubleValue(),
415 alt_node->getDoubleValue());
417 double nav_elev = _navaid->get_elev_ft();
418 SGVec3d aircraft = SGVec3d::fromGeod(pos);
419 double loc_dist = dist(aircraft, _navaid->cart());
420 loc_dist_node->setDoubleValue( loc_dist );
421 bool is_loc = loc_node->getBoolValue();
422 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
425 //////////////////////////////////////////////////////////
426 // compute forward and reverse wgs84 headings to localizer
427 //////////////////////////////////////////////////////////
429 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
430 heading_node->setDoubleValue(hdg);
431 double radial = az2 - twist;
432 double recip = radial + 180.0;
433 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
434 radial_node->setDoubleValue( radial );
435 recip_radial_node->setDoubleValue( recip );
437 //////////////////////////////////////////////////////////
438 // compute the target/selected radial in "true" heading
439 //////////////////////////////////////////////////////////
441 target_radial = sel_radial_node->getDoubleValue();
444 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
445 double trtrue = target_radial + twist;
446 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
447 target_radial_true_node->setDoubleValue( trtrue );
449 //////////////////////////////////////////////////////////
450 // adjust reception range for altitude
451 // FIXME: make sure we are using the navdata range now that
452 // it is valid in the data file
453 //////////////////////////////////////////////////////////
455 double offset = radial - target_radial;
456 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
458 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
459 loc_dist * SG_METER_TO_NM );
462 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
465 double effective_range_m = effective_range * SG_NM_TO_METER;
467 //////////////////////////////////////////////////////////
468 // compute signal quality
469 // 100% within effective_range
470 // decreases 1/x^2 further out
471 //////////////////////////////////////////////////////////
472 double last_signal_quality_norm = signal_quality_norm;
474 if ( loc_dist < effective_range_m ) {
475 signal_quality_norm = 1.0;
477 double range_exceed_norm = loc_dist/effective_range_m;
478 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
481 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
482 signal_quality_norm, dt );
484 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
485 bool inrange = signal_quality_norm > 0.2;
486 inrange_node->setBoolValue( inrange );
488 //////////////////////////////////////////////////////////
489 // compute to/from flag status
490 //////////////////////////////////////////////////////////
495 double offset = fabs(radial - target_radial);
496 _toFlag = (offset > 90.0 && offset < 270.0);
498 _fromFlag = !_toFlag;
500 _toFlag = _fromFlag = false;
504 double r = target_radial - radial;
505 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
508 if (falseCoursesEnabledNode->getBoolValue()) {
509 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
510 // zeros i.e. six courses: one front course, one back course, and four
511 // false courses. Three of the six are reverse sensing.
512 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
514 // no false courses, but we do need to create a back course
515 if (fabs(r) > 90.0) { // front course
516 _cdiDeflection = r - copysign(180.0, r);
518 _cdiDeflection = r; // back course
521 _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
522 } // of false courses disabled
524 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
525 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
527 if (backcourse_node->getBoolValue()) {
528 _cdiDeflection = -_cdiDeflection;
531 // handle the TO side of the VOR
532 if (fabs(r) > 90.0) {
533 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
536 } // of non-localiser case
538 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
539 _cdiDeflection *= signal_quality_norm;
541 // cross-track error (in metres)
542 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
544 updateGlideSlope(dt, aircraft, signal_quality_norm);
547 last_loc_dist = loc_dist;
550 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
552 _gsNeedleDeflection = 0.0;
553 if (!_gs || !inrange_node->getBoolValue()) {
554 gs_dist_node->setDoubleValue( 0.0 );
555 gs_inrange_node->setBoolValue(false);
556 _gsNeedleDeflection = 0.0;
557 _gsNeedleDeflectionNorm = 0.0;
561 double gsDist = dist(aircraft, _gsCart);
562 gs_dist_node->setDoubleValue(gsDist);
563 bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
564 gs_inrange_node->setBoolValue(gsInRange);
567 _gsNeedleDeflection = 0.0;
568 _gsNeedleDeflectionNorm = 0.0;
572 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
573 // The positive GS axis points along the runway in the landing direction,
574 // toward the far end, not toward the approach area, so we need a - sign here:
575 double dot_h = -dot(pos, _gsAxis);
576 double dot_v = dot(pos, _gsVertical);
577 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
578 double deflectionAngle = target_gs - angle;
580 if (falseCoursesEnabledNode->getBoolValue()) {
581 // Construct false glideslopes. The scale factor of 1.5
582 // in the sawtooth gives a period of 6 degrees.
583 // There will be zeros at 3, 6r, 9, 12r et cetera
584 // where "r" indicates reverse sensing.
585 // This is is consistent with conventional pilot lore
586 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
587 // but inconsistent with
588 // http://www.freepatentsonline.com/3757338.html
590 // It may be that some of each exist.
591 if (deflectionAngle < 0) {
592 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
594 // no false GS below the true GS
598 _gsNeedleDeflection = deflectionAngle * 5.0;
599 _gsNeedleDeflection *= signal_quality_norm;
601 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
602 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
604 //////////////////////////////////////////////////////////
605 // Calculate desired rate of climb for intercepting the GS
606 //////////////////////////////////////////////////////////
607 double gs_diff = target_gs - angle;
608 // convert desired vertical path angle into a climb rate
609 double des_angle = angle - 10 * gs_diff;
610 /* printf("target_gs=%.1f angle=%.1f gs_diff=%.1f des_angle=%.1f\n",
611 target_gs, angle, gs_diff, des_angle); */
613 // estimate horizontal speed towards ILS in meters per minute
614 double elapsedDistance = last_x - gsDist;
617 double new_vel = ( elapsedDistance / dt );
618 horiz_vel = 0.99 * horiz_vel + 0.01 * new_vel;
619 /* printf("vel=%.1f (dist=%.1f dt=%.2f)\n", horiz_vel, elapsedDistance, dt);*/
621 gs_rate_of_climb_node
622 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
623 * horiz_vel * SG_METER_TO_FEET );
624 gs_rate_of_climb_fpm_node
625 ->setDoubleValue( gs_rate_of_climb_node->getDoubleValue() * 60 );
628 void FGNavRadio::updateDME(const SGVec3d& aircraft)
630 if (!_dme || !dme_serviceable_node->getBoolValue()) {
635 double dme_distance = dist(aircraft, _dme->cart());
636 _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
639 void FGNavRadio::valueChanged (SGPropertyNode* prop)
641 if (prop == gps_course_node) {
642 if (!nav_slaved_to_gps_node->getBoolValue()) {
646 // GPS desired course has changed, sync up our selected-course
647 double v = prop->getDoubleValue();
648 if (v != sel_radial_node->getDoubleValue()) {
649 sel_radial_node->setDoubleValue(v);
651 } else if (prop == nav_slaved_to_gps_node) {
652 if (prop->getBoolValue()) {
653 // slaved-to-GPS activated, sync up selected course
654 sel_radial_node->setDoubleValue(gps_course_node->getDoubleValue());
659 void FGNavRadio::updateGPSSlaved()
661 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
663 _toFlag = gps_to_flag_node->getBoolValue();
664 _fromFlag = gps_from_flag_node->getBoolValue();
666 bool gpsValid = (_toFlag | _fromFlag);
667 inrange_node->setBoolValue(gpsValid);
669 signal_quality_norm_node->setDoubleValue(0.0);
670 _cdiDeflection = 0.0;
671 _cdiCrossTrackErrorM = 0.0;
672 _gsNeedleDeflection = 0.0;
676 // this is unfortunate, but panel instruments use this value to decide
677 // if the navradio output is valid.
678 signal_quality_norm_node->setDoubleValue(1.0);
680 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
681 // clmap to some range (+/- 10 degrees) as the regular deflection
682 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
684 _cdiCrossTrackErrorM = gps_xtrack_error_nm_node->getDoubleValue() * SG_NM_TO_METER;
685 _gsNeedleDeflection = 0.0; // FIXME, supply this
687 double trtrue = gps_course_node->getDoubleValue() + _magvarNode->getDoubleValue();
688 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
689 target_radial_true_node->setDoubleValue( trtrue );
692 void FGNavRadio::updateCDI(double dt)
694 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
695 bool inrange = inrange_node->getBoolValue();
697 if (tofrom_serviceable_node->getBoolValue()) {
698 to_flag_node->setBoolValue(_toFlag);
699 from_flag_node->setBoolValue(_fromFlag);
701 to_flag_node->setBoolValue(false);
702 from_flag_node->setBoolValue(false);
705 if (!cdi_serviceable) {
706 _cdiDeflection = 0.0;
707 _cdiCrossTrackErrorM = 0.0;
710 cdi_deflection_node->setDoubleValue(_cdiDeflection);
711 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
712 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
714 //////////////////////////////////////////////////////////
715 // compute an approximate ground track heading error
716 //////////////////////////////////////////////////////////
717 double hdg_error = 0.0;
718 if ( inrange && cdi_serviceable ) {
719 double vn = fgGetDouble( "/velocities/speed-north-fps" );
720 double ve = fgGetDouble( "/velocities/speed-east-fps" );
721 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
722 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
724 SGPropertyNode *true_hdg
725 = fgGetNode("/orientation/heading-deg", true);
726 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
728 // cout << "ground track = " << gnd_trk_true
729 // << " orientation = " << true_hdg->getDoubleValue() << endl;
731 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
733 //////////////////////////////////////////////////////////
734 // Calculate a suggested target heading to smoothly intercept
736 //////////////////////////////////////////////////////////
738 // Now that we have cross track heading adjustment built in,
739 // we shouldn't need to overdrive the heading angle within 8km
742 // The cdi deflection should be +/-10 for a full range of deflection
743 // so multiplying this by 3 gives us +/- 30 degrees heading
745 double adjustment = _cdiDeflection * 3.0;
746 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
748 // determine the target heading to fly to intercept the
749 // tgt_radial = target radial (true) + cdi offset adjustmest -
750 // xtrack heading error adjustment
752 double trtrue = target_radial_true_node->getDoubleValue();
753 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
754 // tuned to a localizer and backcourse mode activated
755 trtrue += 180.0; // reverse the target localizer heading
756 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
757 nta_hdg = trtrue - adjustment - hdg_error;
759 nta_hdg = trtrue + adjustment - hdg_error;
762 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
763 target_auto_hdg_node->setDoubleValue( nta_hdg );
765 //////////////////////////////////////////////////////////
766 // compute the time to intercept selected radial (based on
767 // current and last cross track errors and dt
768 //////////////////////////////////////////////////////////
770 if ( inrange && cdi_serviceable ) {
771 double cur_rate = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
772 xrate_ms = 0.99 * xrate_ms + 0.01 * cur_rate;
773 if ( fabs(xrate_ms) > 0.00001 ) {
774 t = _cdiCrossTrackErrorM / xrate_ms;
779 time_to_intercept->setDoubleValue( t );
781 if (!gs_serviceable_node->getBoolValue() ) {
782 _gsNeedleDeflection = 0.0;
783 _gsNeedleDeflectionNorm = 0.0;
785 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
786 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
787 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
789 last_xtrack_error = _cdiCrossTrackErrorM;
792 void FGNavRadio::updateAudio()
794 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
798 // play station ident via audio system if on + ident,
799 // otherwise turn it off
800 if (!power_btn_node->getBoolValue()
801 || !(bus_power_node->getDoubleValue() > 1.0)
802 || !ident_btn_node->getBoolValue()
803 || !audio_btn_node->getBoolValue() ) {
804 _sgr->stop( nav_fx_name );
805 _sgr->stop( dme_fx_name );
809 SGSoundSample *sound = _sgr->find( nav_fx_name );
810 double vol = vol_btn_node->getFloatValue();
811 SG_CLAMP_RANGE(vol, 0.0, 1.0);
813 if ( sound != NULL ) {
814 sound->set_volume( vol );
816 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
819 sound = _sgr->find( dme_fx_name );
820 if ( sound != NULL ) {
821 sound->set_volume( vol );
823 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
826 const int NUM_IDENT_SLOTS = 5;
827 const time_t SLOT_LENGTH = 5; // seconds
829 // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
830 // Each slot is 5 seconds long.
831 // Slots 0 is for DME
832 // the rest are for azimuth.
833 time_t now = globals->get_time_params()->get_cur_time();
834 if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
835 return; // wait longer
839 play_count = ++play_count % NUM_IDENT_SLOTS;
841 // Previous ident is out of time; if still playing, cut it off:
842 _sgr->stop( nav_fx_name );
843 _sgr->stop( dme_fx_name );
844 if (play_count == 0) { // the DME slot
845 if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
847 if (vol > 0.05) _sgr->play_once( dme_fx_name );
850 if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
851 if (vol > 0.05) _sgr->play_once(nav_fx_name);
856 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
858 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
863 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
866 // Update current nav/adf radio stations based on current postition
867 void FGNavRadio::search()
869 _time_before_search_sec = 1.0;
870 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
871 lat_node->getDoubleValue(), alt_node->getDoubleValue());
872 double freq = freq_node->getDoubleValue();
874 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
875 if (nav == _navaid) {
876 return; // found the same as last search, we're done
880 char identBuffer[5] = " ";
882 _dme = globals->get_dmelist()->findByFreq(freq, pos);
884 nav_id_node->setStringValue(nav->get_ident());
885 strncpy(identBuffer, nav->ident().c_str(), 5);
887 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
888 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
889 twist = nav->get_multiuse();
891 if (nav->type() == FGPositioned::VOR) {
892 target_radial = sel_radial_node->getDoubleValue();
894 has_gs_node->setBoolValue(false);
895 } else { // ILS or LOC
896 _gs = globals->get_gslist()->findByFreq(freq, pos);
897 has_gs_node->setBoolValue(_gs != NULL);
898 _localizerWidth = nav->localizerWidth();
900 effective_range = nav->get_range();
902 target_radial = nav->get_multiuse();
903 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
906 int tmp = (int)(_gs->get_multiuse() / 1000.0);
907 target_gs = (double)tmp / 100.0;
909 // until penaltyForNav goes away, we cannot assume we always pick
910 // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
911 // often end up picking the 'wrong' LOC, but the correct GS. To avoid
912 // breaking the basis computation, ensure we use the GS radial and not
913 // the (potentially reversed) LOC radial.
914 double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
915 SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
917 // GS axis unit tangent vector
918 // (along the runway)
919 _gsCart = _gs->cart();
920 _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
922 // GS baseline unit tangent vector
923 // (perpendicular to the runay along the ground)
924 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
925 _gsVertical = cross(baseline, _gsAxis);
926 } // of have glideslope
927 } // of found LOC or ILS
930 } else { // found nothing
933 nav_id_node->setStringValue("");
934 loc_node->setBoolValue(false);
935 has_gs_node->setBoolValue(false);
937 _sgr->remove( nav_fx_name );
938 _sgr->remove( dme_fx_name );
941 is_valid_node->setBoolValue(nav != NULL);
942 id_c1_node->setIntValue( (int)identBuffer[0] );
943 id_c2_node->setIntValue( (int)identBuffer[1] );
944 id_c3_node->setIntValue( (int)identBuffer[2] );
945 id_c4_node->setIntValue( (int)identBuffer[3] );
948 void FGNavRadio::audioNavidChanged()
950 if (_sgr->exists(nav_fx_name)) {
951 _sgr->remove(nav_fx_name);
955 string trans_ident(_navaid->get_trans_ident());
956 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
957 sound->set_volume( 0.3 );
958 if (!_sgr->add( sound, nav_fx_name )) {
959 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
962 if ( _sgr->exists( dme_fx_name ) ) {
963 _sgr->remove( dme_fx_name );
966 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
967 sound->set_volume( 0.3 );
968 _sgr->add( sound, dme_fx_name );
970 int offset = (int)(sg_random() * 30.0);
971 play_count = offset / 4;
972 last_time = globals->get_time_params()->get_cur_time() - offset;
973 } catch (sg_io_exception& e) {
974 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());