1 // navradio.cxx -- class to manage a nav radio instance
3 // Written by Curtis Olson, started April 2000.
5 // Copyright (C) 2000 - 2002 Curtis L. Olson - http://www.flightgear.org/~curt
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
28 #include "navradio.hxx"
32 #include <simgear/sg_inlines.h>
33 #include <simgear/timing/sg_time.hxx>
34 #include <simgear/math/vector.hxx>
35 #include <simgear/math/sg_random.h>
36 #include <simgear/misc/sg_path.hxx>
37 #include <simgear/math/sg_geodesy.hxx>
38 #include <simgear/structure/exception.hxx>
39 #include <simgear/math/interpolater.hxx>
41 #include <Navaids/navrecord.hxx>
43 #include <Airports/runways.hxx>
44 #include <Navaids/navlist.hxx>
45 #include <Main/util.hxx>
50 // General-purpose sawtooth function. Graph looks like this:
53 // Odd symmetry, inversion symmetry about the origin.
54 // Unit slope at the origin.
55 // Max 1, min -1, period 4.
56 // Two zero-crossings per period, one with + slope, one with - slope.
57 // Useful for false localizer courses.
58 static double sawtooth(double xx)
60 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
63 // Calculate a unit vector in the horizontal tangent plane
64 // starting at the given "tail" of the vector and going off
65 // with the given heading.
66 static SGVec3d tangentVector(const SGGeod& tail, const SGVec3d& tail_xyz,
69 // The fudge factor here is presumably intended to improve
70 // numerical stability. I don't know if it is necessary.
71 // It gets divided out later.
74 double az2; // ignored
75 SGGeodesy::direct(tail, heading, fudge, head, az2);
76 head.setElevationM(tail.getElevationM());
77 SGVec3d head_xyz = SGVec3d::fromGeod(head);
78 return (head_xyz - tail_xyz) * (1.0/fudge);
81 // Create a "serviceable" node with a default value of "true"
82 SGPropertyNode_ptr createServiceableProp(SGPropertyNode* aParent, const char* aName)
84 SGPropertyNode_ptr n = (aParent->getChild(aName, 0, true)->getChild("serviceable", 0, true));
85 simgear::props::Type typ = n->getType();
86 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED)) {
87 n->setBoolValue(true);
93 FGNavRadio::FGNavRadio(SGPropertyNode *node) :
94 lon_node(fgGetNode("/position/longitude-deg", true)),
95 lat_node(fgGetNode("/position/latitude-deg", true)),
96 alt_node(fgGetNode("/position/altitude-ft", true)),
103 last_xtrack_error(0.0),
105 _localizerWidth(5.0),
106 _name(node->getStringValue("name", "nav")),
107 _num(node->getIntValue("number", 0)),
108 _time_before_search_sec(-1.0),
111 SGPath path( globals->get_fg_root() );
113 term.append( "Navaids/range.term" );
115 low.append( "Navaids/range.low" );
117 high.append( "Navaids/range.high" );
119 term_tbl = new SGInterpTable( term.str() );
120 low_tbl = new SGInterpTable( low.str() );
121 high_tbl = new SGInterpTable( high.str() );
124 string branch("/instrumentation/" + _name);
125 _radio_node = fgGetNode(branch.c_str(), _num, true);
130 FGNavRadio::~FGNavRadio()
132 if (gps_course_node) {
133 gps_course_node->removeChangeListener(this);
136 if (nav_slaved_to_gps_node) {
137 nav_slaved_to_gps_node->removeChangeListener(this);
149 SGSoundMgr *smgr = globals->get_soundmgr();
150 _sgr = smgr->find("avionics", true);
151 _sgr->tie_to_listener();
155 SGPropertyNode* node = _radio_node.get();
157 fgGetNode(("/systems/electrical/outputs/" + _name).c_str(), true);
160 is_valid_node = node->getChild("data-is-valid", 0, true);
161 power_btn_node = node->getChild("power-btn", 0, true);
162 power_btn_node->setBoolValue( true );
163 vol_btn_node = node->getChild("volume", 0, true);
164 ident_btn_node = node->getChild("ident", 0, true);
165 ident_btn_node->setBoolValue( true );
166 audio_btn_node = node->getChild("audio-btn", 0, true);
167 audio_btn_node->setBoolValue( true );
168 backcourse_node = node->getChild("back-course-btn", 0, true);
169 backcourse_node->setBoolValue( false );
171 nav_serviceable_node = node->getChild("serviceable", 0, true);
172 cdi_serviceable_node = createServiceableProp(node, "cdi");
173 gs_serviceable_node = createServiceableProp(node, "gs");
174 tofrom_serviceable_node = createServiceableProp(node, "to-from");
175 dme_serviceable_node = createServiceableProp(node, "dme");
177 falseCoursesEnabledNode =
178 fgGetNode("/sim/realism/false-radio-courses-enabled");
179 if (!falseCoursesEnabledNode) {
180 falseCoursesEnabledNode =
181 fgGetNode("/sim/realism/false-radio-courses-enabled", true);
182 falseCoursesEnabledNode->setBoolValue(true);
186 SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
187 freq_node = subnode->getChild("selected-mhz", 0, true);
188 alt_freq_node = subnode->getChild("standby-mhz", 0, true);
189 fmt_freq_node = subnode->getChild("selected-mhz-fmt", 0, true);
190 fmt_alt_freq_node = subnode->getChild("standby-mhz-fmt", 0, true);
193 subnode = node->getChild("radials", 0, true);
194 sel_radial_node = subnode->getChild("selected-deg", 0, true);
195 radial_node = subnode->getChild("actual-deg", 0, true);
196 recip_radial_node = subnode->getChild("reciprocal-radial-deg", 0, true);
197 target_radial_true_node = subnode->getChild("target-radial-deg", 0, true);
198 target_auto_hdg_node = subnode->getChild("target-auto-hdg-deg", 0, true);
201 heading_node = node->getChild("heading-deg", 0, true);
202 time_to_intercept = node->getChild("time-to-intercept-sec", 0, true);
203 to_flag_node = node->getChild("to-flag", 0, true);
204 from_flag_node = node->getChild("from-flag", 0, true);
205 inrange_node = node->getChild("in-range", 0, true);
206 signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
207 cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
208 cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
209 cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
210 cdi_xtrack_hdg_err_node
211 = node->getChild("crosstrack-heading-error-deg", 0, true);
212 has_gs_node = node->getChild("has-gs", 0, true);
213 loc_node = node->getChild("nav-loc", 0, true);
214 loc_dist_node = node->getChild("nav-distance", 0, true);
215 gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
216 gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 0, true);
217 gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
218 gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
219 gs_rate_of_climb_fpm_node = node->getChild("gs-rate-of-climb-fpm", 0, true);
220 gs_dist_node = node->getChild("gs-distance", 0, true);
221 gs_inrange_node = node->getChild("gs-in-range", 0, true);
223 nav_id_node = node->getChild("nav-id", 0, true);
224 id_c1_node = node->getChild("nav-id_asc1", 0, true);
225 id_c2_node = node->getChild("nav-id_asc2", 0, true);
226 id_c3_node = node->getChild("nav-id_asc3", 0, true);
227 id_c4_node = node->getChild("nav-id_asc4", 0, true);
229 // gps slaving support
230 nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
231 nav_slaved_to_gps_node->addChangeListener(this);
233 gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
234 gps_to_flag_node = fgGetNode("/instrumentation/gps/to-flag", true);
235 gps_from_flag_node = fgGetNode("/instrumentation/gps/from-flag", true);
236 gps_has_gs_node = fgGetNode("/instrumentation/gps/has-gs", true);
237 gps_course_node = fgGetNode("/instrumentation/gps/desired-course-deg", true);
238 gps_course_node->addChangeListener(this);
240 gps_xtrack_error_nm_node = fgGetNode("/instrumentation/gps/wp/wp[1]/course-error-nm", true);
241 _magvarNode = fgGetNode("/environment/magnetic-variation-deg", true);
243 std::ostringstream temp;
244 temp << _name << "nav-ident" << _num;
245 nav_fx_name = temp.str();
246 temp << _name << "dme-ident" << _num;
247 dme_fx_name = temp.str();
253 tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
254 tie("operable", SGRawValueMethods<FGNavRadio, bool>(*this, &FGNavRadio::isOperable, NULL));
259 FGNavRadio::unbind ()
261 for (unsigned int t=0; t<_tiedNodes.size(); ++t) {
262 _tiedNodes[t]->untie();
268 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
269 double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
270 double nominalRange )
272 if (nominalRange <= 0.0) {
273 nominalRange = FG_NAV_DEFAULT_RANGE;
276 // extend out actual usable range to be 1.3x the published safe range
277 const double usability_factor = 1.3;
279 // assumptions we model the standard service volume, plus
280 // ... rather than specifying a cylinder, we model a cone that
281 // contains the cylinder. Then we put an upside down cone on top
282 // to model diminishing returns at too-high altitudes.
284 // altitude difference
285 double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
286 // cout << "aircraft elev = " << aircraftElev * SG_METER_TO_FEET
287 // << " station elev = " << stationElev << endl;
289 if ( nominalRange < 25.0 + SG_EPSILON ) {
290 // Standard Terminal Service Volume
291 return term_tbl->interpolate( alt ) * usability_factor;
292 } else if ( nominalRange < 50.0 + SG_EPSILON ) {
293 // Standard Low Altitude Service Volume
294 // table is based on range of 40, scale to actual range
295 return low_tbl->interpolate( alt ) * nominalRange / 40.0
298 // Standard High Altitude Service Volume
299 // table is based on range of 130, scale to actual range
300 return high_tbl->interpolate( alt ) * nominalRange / 130.0
306 // model standard ILS service volumes as per AIM 1-1-9
307 double FGNavRadio::adjustILSRange( double stationElev, double aircraftElev,
308 double offsetDegrees, double distance )
310 // assumptions we model the standard service volume, plus
312 // altitude difference
313 // double alt = ( aircraftElev * SG_METER_TO_FEET - stationElev );
314 // double offset = fabs( offsetDegrees );
316 // if ( offset < 10 ) {
317 // return FG_ILS_DEFAULT_RANGE;
318 // } else if ( offset < 35 ) {
319 // return 10 + (35 - offset) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
320 // } else if ( offset < 45 ) {
321 // return (45 - offset);
322 // } else if ( offset > 170 ) {
323 // return FG_ILS_DEFAULT_RANGE;
324 // } else if ( offset > 145 ) {
325 // return 10 + (offset - 145) * (FG_ILS_DEFAULT_RANGE - 10) / 25;
326 // } else if ( offset > 135 ) {
327 // return (offset - 135);
331 return FG_LOC_DEFAULT_RANGE;
335 //////////////////////////////////////////////////////////////////////////
336 // Update the various nav values based on position and valid tuned in navs
337 //////////////////////////////////////////////////////////////////////////
339 FGNavRadio::update(double dt)
345 // Create "formatted" versions of the nav frequencies for
346 // instrument displays.
348 sprintf( tmp, "%.2f", freq_node->getDoubleValue() );
349 fmt_freq_node->setStringValue(tmp);
350 sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
351 fmt_alt_freq_node->setStringValue(tmp);
353 if (power_btn_node->getBoolValue()
354 && (bus_power_node->getDoubleValue() > 1.0)
355 && nav_serviceable_node->getBoolValue() )
358 if (nav_slaved_to_gps_node->getBoolValue()) {
372 void FGNavRadio::clearOutputs()
374 inrange_node->setBoolValue( false );
375 cdi_deflection_node->setDoubleValue( 0.0 );
376 cdi_deflection_norm_node->setDoubleValue( 0.0 );
377 cdi_xtrack_error_node->setDoubleValue( 0.0 );
378 cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
379 time_to_intercept->setDoubleValue( 0.0 );
380 gs_deflection_node->setDoubleValue( 0.0 );
381 gs_deflection_deg_node->setDoubleValue(0.0);
382 gs_deflection_norm_node->setDoubleValue(0.0);
383 gs_inrange_node->setBoolValue( false );
384 loc_node->setBoolValue( false );
385 has_gs_node->setBoolValue(false);
387 to_flag_node->setBoolValue( false );
388 from_flag_node->setBoolValue( false );
394 void FGNavRadio::updateReceiver(double dt)
396 // Do a nav station search only once a second to reduce
397 // unnecessary work. (Also, make sure to do this before caching
399 _time_before_search_sec -= dt;
400 if ( _time_before_search_sec < 0 ) {
405 _cdiDeflection = 0.0;
406 _cdiCrossTrackErrorM = 0.0;
407 _toFlag = _fromFlag = false;
408 _gsNeedleDeflection = 0.0;
409 _gsNeedleDeflectionNorm = 0.0;
410 inrange_node->setBoolValue(false);
414 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
415 lat_node->getDoubleValue(),
416 alt_node->getDoubleValue());
418 double nav_elev = _navaid->get_elev_ft();
419 SGVec3d aircraft = SGVec3d::fromGeod(pos);
420 double loc_dist = dist(aircraft, _navaid->cart());
421 loc_dist_node->setDoubleValue( loc_dist );
422 bool is_loc = loc_node->getBoolValue();
423 double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
426 //////////////////////////////////////////////////////////
427 // compute forward and reverse wgs84 headings to localizer
428 //////////////////////////////////////////////////////////
430 SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
431 heading_node->setDoubleValue(hdg);
432 double radial = az2 - twist;
433 double recip = radial + 180.0;
434 SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
435 radial_node->setDoubleValue( radial );
436 recip_radial_node->setDoubleValue( recip );
438 //////////////////////////////////////////////////////////
439 // compute the target/selected radial in "true" heading
440 //////////////////////////////////////////////////////////
442 target_radial = sel_radial_node->getDoubleValue();
445 // VORs need twist (mag-var) added; ILS/LOCs don't but we set twist to 0.0
446 double trtrue = target_radial + twist;
447 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
448 target_radial_true_node->setDoubleValue( trtrue );
450 //////////////////////////////////////////////////////////
451 // adjust reception range for altitude
452 // FIXME: make sure we are using the navdata range now that
453 // it is valid in the data file
454 //////////////////////////////////////////////////////////
456 double offset = radial - target_radial;
457 SG_NORMALIZE_RANGE(offset, -180.0, 180.0);
459 = adjustILSRange( nav_elev, pos.getElevationM(), offset,
460 loc_dist * SG_METER_TO_NM );
463 = adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
466 double effective_range_m = effective_range * SG_NM_TO_METER;
468 //////////////////////////////////////////////////////////
469 // compute signal quality
470 // 100% within effective_range
471 // decreases 1/x^2 further out
472 //////////////////////////////////////////////////////////
473 double last_signal_quality_norm = signal_quality_norm;
475 if ( loc_dist < effective_range_m ) {
476 signal_quality_norm = 1.0;
478 double range_exceed_norm = loc_dist/effective_range_m;
479 signal_quality_norm = 1/(range_exceed_norm*range_exceed_norm);
482 signal_quality_norm = fgGetLowPass( last_signal_quality_norm,
483 signal_quality_norm, dt );
485 signal_quality_norm_node->setDoubleValue( signal_quality_norm );
486 bool inrange = signal_quality_norm > 0.2;
487 inrange_node->setBoolValue( inrange );
489 //////////////////////////////////////////////////////////
490 // compute to/from flag status
491 //////////////////////////////////////////////////////////
496 double offset = fabs(radial - target_radial);
497 _toFlag = (offset > 90.0 && offset < 270.0);
499 _fromFlag = !_toFlag;
501 _toFlag = _fromFlag = false;
505 double r = target_radial - radial;
506 SG_NORMALIZE_RANGE(r, -180.0, 180.0);
509 if (falseCoursesEnabledNode->getBoolValue()) {
510 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
511 // zeros i.e. six courses: one front course, one back course, and four
512 // false courses. Three of the six are reverse sensing.
513 _cdiDeflection = 30.0 * sawtooth(r / 30.0);
515 // no false courses, but we do need to create a back course
516 if (fabs(r) > 90.0) { // front course
517 _cdiDeflection = r - copysign(180.0, r);
519 _cdiDeflection = r; // back course
522 _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
523 } // of false courses disabled
525 const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
526 _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
528 if (backcourse_node->getBoolValue()) {
529 _cdiDeflection = -_cdiDeflection;
532 // handle the TO side of the VOR
533 if (fabs(r) > 90.0) {
534 r = ( r<0.0 ? -r-180.0 : -r+180.0 );
537 } // of non-localiser case
539 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
540 _cdiDeflection *= signal_quality_norm;
542 // cross-track error (in metres)
543 _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
545 updateGlideSlope(dt, aircraft, signal_quality_norm);
548 last_loc_dist = loc_dist;
551 void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
553 _gsNeedleDeflection = 0.0;
554 if (!_gs || !inrange_node->getBoolValue()) {
555 gs_dist_node->setDoubleValue( 0.0 );
556 gs_inrange_node->setBoolValue(false);
557 _gsNeedleDeflection = 0.0;
558 _gsNeedleDeflectionNorm = 0.0;
562 double gsDist = dist(aircraft, _gsCart);
563 gs_dist_node->setDoubleValue(gsDist);
564 bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
565 gs_inrange_node->setBoolValue(gsInRange);
568 _gsNeedleDeflection = 0.0;
569 _gsNeedleDeflectionNorm = 0.0;
573 SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
574 // The positive GS axis points along the runway in the landing direction,
575 // toward the far end, not toward the approach area, so we need a - sign here:
576 double dot_h = -dot(pos, _gsAxis);
577 double dot_v = dot(pos, _gsVertical);
578 double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
579 double deflectionAngle = target_gs - angle;
581 if (falseCoursesEnabledNode->getBoolValue()) {
582 // Construct false glideslopes. The scale factor of 1.5
583 // in the sawtooth gives a period of 6 degrees.
584 // There will be zeros at 3, 6r, 9, 12r et cetera
585 // where "r" indicates reverse sensing.
586 // This is is consistent with conventional pilot lore
587 // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
588 // but inconsistent with
589 // http://www.freepatentsonline.com/3757338.html
591 // It may be that some of each exist.
592 if (deflectionAngle < 0) {
593 deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
595 // no false GS below the true GS
599 _gsNeedleDeflection = deflectionAngle * 5.0;
600 _gsNeedleDeflection *= signal_quality_norm;
602 SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
603 _gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
605 //////////////////////////////////////////////////////////
606 // Calculate desired rate of climb for intercepting the GS
607 //////////////////////////////////////////////////////////
608 double gs_diff = target_gs - angle;
609 // convert desired vertical path angle into a climb rate
610 double des_angle = angle - 10 * gs_diff;
611 /* printf("target_gs=%.1f angle=%.1f gs_diff=%.1f des_angle=%.1f\n",
612 target_gs, angle, gs_diff, des_angle); */
614 // estimate horizontal speed towards ILS in meters per minute
615 double elapsedDistance = last_x - gsDist;
618 double new_vel = ( elapsedDistance / dt );
619 horiz_vel = 0.99 * horiz_vel + 0.01 * new_vel;
620 /* printf("vel=%.1f (dist=%.1f dt=%.2f)\n", horiz_vel, elapsedDistance, dt);*/
622 gs_rate_of_climb_node
623 ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
624 * horiz_vel * SG_METER_TO_FEET );
625 gs_rate_of_climb_fpm_node
626 ->setDoubleValue( gs_rate_of_climb_node->getDoubleValue() * 60 );
629 void FGNavRadio::updateDME(const SGVec3d& aircraft)
631 if (!_dme || !dme_serviceable_node->getBoolValue()) {
636 double dme_distance = dist(aircraft, _dme->cart());
637 _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
640 void FGNavRadio::valueChanged (SGPropertyNode* prop)
642 if (prop == gps_course_node) {
643 if (!nav_slaved_to_gps_node->getBoolValue()) {
647 // GPS desired course has changed, sync up our selected-course
648 double v = prop->getDoubleValue();
649 if (v != sel_radial_node->getDoubleValue()) {
650 sel_radial_node->setDoubleValue(v);
652 } else if (prop == nav_slaved_to_gps_node) {
653 if (prop->getBoolValue()) {
654 // slaved-to-GPS activated, sync up selected course
655 sel_radial_node->setDoubleValue(gps_course_node->getDoubleValue());
660 void FGNavRadio::updateGPSSlaved()
662 has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
664 _toFlag = gps_to_flag_node->getBoolValue();
665 _fromFlag = gps_from_flag_node->getBoolValue();
667 bool gpsValid = (_toFlag | _fromFlag);
668 inrange_node->setBoolValue(gpsValid);
670 signal_quality_norm_node->setDoubleValue(0.0);
671 _cdiDeflection = 0.0;
672 _cdiCrossTrackErrorM = 0.0;
673 _gsNeedleDeflection = 0.0;
677 // this is unfortunate, but panel instruments use this value to decide
678 // if the navradio output is valid.
679 signal_quality_norm_node->setDoubleValue(1.0);
681 _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
682 // clmap to some range (+/- 10 degrees) as the regular deflection
683 SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
685 _cdiCrossTrackErrorM = gps_xtrack_error_nm_node->getDoubleValue() * SG_NM_TO_METER;
686 _gsNeedleDeflection = 0.0; // FIXME, supply this
688 double trtrue = gps_course_node->getDoubleValue() + _magvarNode->getDoubleValue();
689 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
690 target_radial_true_node->setDoubleValue( trtrue );
693 void FGNavRadio::updateCDI(double dt)
695 bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
696 bool inrange = inrange_node->getBoolValue();
698 if (tofrom_serviceable_node->getBoolValue()) {
699 to_flag_node->setBoolValue(_toFlag);
700 from_flag_node->setBoolValue(_fromFlag);
702 to_flag_node->setBoolValue(false);
703 from_flag_node->setBoolValue(false);
706 if (!cdi_serviceable) {
707 _cdiDeflection = 0.0;
708 _cdiCrossTrackErrorM = 0.0;
711 cdi_deflection_node->setDoubleValue(_cdiDeflection);
712 cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
713 cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
715 //////////////////////////////////////////////////////////
716 // compute an approximate ground track heading error
717 //////////////////////////////////////////////////////////
718 double hdg_error = 0.0;
719 if ( inrange && cdi_serviceable ) {
720 double vn = fgGetDouble( "/velocities/speed-north-fps" );
721 double ve = fgGetDouble( "/velocities/speed-east-fps" );
722 double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
723 if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
725 SGPropertyNode *true_hdg
726 = fgGetNode("/orientation/heading-deg", true);
727 hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
729 // cout << "ground track = " << gnd_trk_true
730 // << " orientation = " << true_hdg->getDoubleValue() << endl;
732 cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
734 //////////////////////////////////////////////////////////
735 // Calculate a suggested target heading to smoothly intercept
737 //////////////////////////////////////////////////////////
739 // Now that we have cross track heading adjustment built in,
740 // we shouldn't need to overdrive the heading angle within 8km
743 // The cdi deflection should be +/-10 for a full range of deflection
744 // so multiplying this by 3 gives us +/- 30 degrees heading
746 double adjustment = _cdiDeflection * 3.0;
747 SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
749 // determine the target heading to fly to intercept the
750 // tgt_radial = target radial (true) + cdi offset adjustmest -
751 // xtrack heading error adjustment
753 double trtrue = target_radial_true_node->getDoubleValue();
754 if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
755 // tuned to a localizer and backcourse mode activated
756 trtrue += 180.0; // reverse the target localizer heading
757 SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
758 nta_hdg = trtrue - adjustment - hdg_error;
760 nta_hdg = trtrue + adjustment - hdg_error;
763 SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
764 target_auto_hdg_node->setDoubleValue( nta_hdg );
766 //////////////////////////////////////////////////////////
767 // compute the time to intercept selected radial (based on
768 // current and last cross track errors and dt
769 //////////////////////////////////////////////////////////
771 if ( inrange && cdi_serviceable ) {
772 double cur_rate = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
773 xrate_ms = 0.99 * xrate_ms + 0.01 * cur_rate;
774 if ( fabs(xrate_ms) > 0.00001 ) {
775 t = _cdiCrossTrackErrorM / xrate_ms;
780 time_to_intercept->setDoubleValue( t );
782 if (!gs_serviceable_node->getBoolValue() ) {
783 _gsNeedleDeflection = 0.0;
784 _gsNeedleDeflectionNorm = 0.0;
786 gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
787 gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
788 gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
790 last_xtrack_error = _cdiCrossTrackErrorM;
793 void FGNavRadio::updateAudio()
795 if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
799 // play station ident via audio system if on + ident,
800 // otherwise turn it off
801 if (!power_btn_node->getBoolValue()
802 || !(bus_power_node->getDoubleValue() > 1.0)
803 || !ident_btn_node->getBoolValue()
804 || !audio_btn_node->getBoolValue() ) {
805 _sgr->stop( nav_fx_name );
806 _sgr->stop( dme_fx_name );
810 SGSoundSample *sound = _sgr->find( nav_fx_name );
811 double vol = vol_btn_node->getFloatValue();
812 SG_CLAMP_RANGE(vol, 0.0, 1.0);
814 if ( sound != NULL ) {
815 sound->set_volume( vol );
817 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
820 sound = _sgr->find( dme_fx_name );
821 if ( sound != NULL ) {
822 sound->set_volume( vol );
824 SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
827 const int NUM_IDENT_SLOTS = 5;
828 const time_t SLOT_LENGTH = 5; // seconds
830 // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
831 // Each slot is 5 seconds long.
832 // Slots 0 is for DME
833 // the rest are for azimuth.
834 time_t now = globals->get_time_params()->get_cur_time();
835 if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
836 return; // wait longer
840 play_count = ++play_count % NUM_IDENT_SLOTS;
842 // Previous ident is out of time; if still playing, cut it off:
843 _sgr->stop( nav_fx_name );
844 _sgr->stop( dme_fx_name );
845 if (play_count == 0) { // the DME slot
846 if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
848 if (vol > 0.05) _sgr->play_once( dme_fx_name );
851 if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
852 if (vol > 0.05) _sgr->play_once(nav_fx_name);
857 FGNavRecord* FGNavRadio::findPrimaryNavaid(const SGGeod& aPos, double aFreqMHz)
859 FGNavRecord* nav = globals->get_navlist()->findByFreq(aFreqMHz, aPos);
864 return globals->get_loclist()->findByFreq(aFreqMHz, aPos);
867 // Update current nav/adf radio stations based on current postition
868 void FGNavRadio::search()
870 _time_before_search_sec = 1.0;
871 SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
872 lat_node->getDoubleValue(), alt_node->getDoubleValue());
873 double freq = freq_node->getDoubleValue();
875 FGNavRecord* nav = findPrimaryNavaid(pos, freq);
876 if (nav == _navaid) {
877 return; // found the same as last search, we're done
881 char identBuffer[5] = " ";
883 _dme = globals->get_dmelist()->findByFreq(freq, pos);
885 nav_id_node->setStringValue(nav->get_ident());
886 strncpy(identBuffer, nav->ident().c_str(), 5);
888 effective_range = adjustNavRange(nav->get_elev_ft(), pos.getElevationM(), nav->get_range());
889 loc_node->setBoolValue(nav->type() != FGPositioned::VOR);
890 twist = nav->get_multiuse();
892 if (nav->type() == FGPositioned::VOR) {
893 target_radial = sel_radial_node->getDoubleValue();
895 has_gs_node->setBoolValue(false);
896 } else { // ILS or LOC
897 _gs = globals->get_gslist()->findByFreq(freq, pos);
898 has_gs_node->setBoolValue(_gs != NULL);
899 _localizerWidth = nav->localizerWidth();
901 effective_range = nav->get_range();
903 target_radial = nav->get_multiuse();
904 SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
907 int tmp = (int)(_gs->get_multiuse() / 1000.0);
908 target_gs = (double)tmp / 100.0;
910 // until penaltyForNav goes away, we cannot assume we always pick
911 // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
912 // often end up picking the 'wrong' LOC, but the correct GS. To avoid
913 // breaking the basis computation, ensure we use the GS radial and not
914 // the (potentially reversed) LOC radial.
915 double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
916 SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
918 // GS axis unit tangent vector
919 // (along the runway)
920 _gsCart = _gs->cart();
921 _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
923 // GS baseline unit tangent vector
924 // (perpendicular to the runay along the ground)
925 SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
926 _gsVertical = cross(baseline, _gsAxis);
927 } // of have glideslope
928 } // of found LOC or ILS
931 } else { // found nothing
934 nav_id_node->setStringValue("");
935 loc_node->setBoolValue(false);
936 has_gs_node->setBoolValue(false);
938 _sgr->remove( nav_fx_name );
939 _sgr->remove( dme_fx_name );
942 is_valid_node->setBoolValue(nav != NULL);
943 id_c1_node->setIntValue( (int)identBuffer[0] );
944 id_c2_node->setIntValue( (int)identBuffer[1] );
945 id_c3_node->setIntValue( (int)identBuffer[2] );
946 id_c4_node->setIntValue( (int)identBuffer[3] );
949 void FGNavRadio::audioNavidChanged()
951 if (_sgr->exists(nav_fx_name)) {
952 _sgr->remove(nav_fx_name);
956 string trans_ident(_navaid->get_trans_ident());
957 SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
958 sound->set_volume( 0.3 );
959 if (!_sgr->add( sound, nav_fx_name )) {
960 SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
963 if ( _sgr->exists( dme_fx_name ) ) {
964 _sgr->remove( dme_fx_name );
967 sound = morse.make_ident( trans_ident, HI_FREQUENCY );
968 sound->set_volume( 0.3 );
969 _sgr->add( sound, dme_fx_name );
971 int offset = (int)(sg_random() * 30.0);
972 play_count = offset / 4;
973 last_time = globals->get_time_params()->get_cur_time() - offset;
974 } catch (sg_io_exception& e) {
975 SG_LOG(SG_GENERAL, SG_ALERT, e.getFormattedMessage());