1 // navradio.cxx -- class to manage a nav radio instance
3 // Written by Curtis Olson, started April 2000.
4 // Rewritten by Torsten Dreyer, August 2011
6 // Copyright (C) 2000 - 2002 Curtis L. Olson - http://www.flightgear.org/~curt
8 // This program is free software; you can redistribute it and/or
9 // modify it under the terms of the GNU General Public License as
10 // published by the Free Software Foundation; either version 2 of the
11 // License, or (at your option) any later version.
13 // This program is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
27 #include "newnavradio.hxx"
30 #include <boost/foreach.hpp>
32 #include <simgear/math/SGMath.hxx>
33 #include <simgear/math/interpolater.hxx>
34 #include <simgear/sg_inlines.h>
35 #include <simgear/props/propertyObject.hxx>
37 #include <Main/fg_props.hxx>
38 #include <Navaids/navlist.hxx>
39 #include <Sound/audioident.hxx>
41 #include "navradio.hxx"
44 namespace Instrumentation {
46 using simgear::PropertyObject;
48 /* --------------The Navigation Indicator ----------------------------- */
52 NavIndicator( SGPropertyNode * rootNode ) :
53 _cdi( rootNode->getNode("heading-needle-deflection", true ) ),
54 _cdiNorm( rootNode->getNode("heading-needle-deflection-norm", true ) ),
55 _course( rootNode->getNode("radials/selected-deg", true ) ),
56 _toFlag( rootNode->getNode("to-flag", true ) ),
57 _fromFlag( rootNode->getNode("from-flag", true ) ),
58 _signalQuality( rootNode->getNode("signal-quality-norm", true ) ),
59 _hasGS( rootNode->getNode("has-gs", true ) ),
60 _gsDeflection(rootNode->getNode("gs-needle-deflection", true )),
61 _gsDeflectionDeg(rootNode->getNode("gs-needle-deflection-deg", true )),
62 _gsDeflectionNorm(rootNode->getNode("gs-needle-deflection-norm", true ))
66 virtual ~NavIndicator() {}
69 * set the normalized CDI deflection
70 * @param norm the cdi deflection normalized [-1..1]
72 void setCDI( double norm )
79 * set the normalized GS deflection
80 * @param norm the gs deflection normalized to [-1..1]
82 void setGS( double norm )
84 _gsDeflectionNorm = norm;
85 _gsDeflectionDeg = norm * 0.7;
86 _gsDeflection = norm * 3.5;
89 void setGS( bool enabled )
97 void showFrom( bool on )
102 void showTo( bool on )
107 void setSelectedCourse( double course )
112 double getSelectedCourse() const
114 return SGMiscd::normalizePeriodic(0.0, 360.0, _course );
117 void setSignalQuality( double signalQuality )
119 _signalQuality = signalQuality;
123 PropertyObject<double> _cdi;
124 PropertyObject<double> _cdiNorm;
125 PropertyObject<double> _course;
126 PropertyObject<double> _toFlag;
127 PropertyObject<double> _fromFlag;
128 PropertyObject<double> _signalQuality;
129 PropertyObject<double> _hasGS;
130 PropertyObject<double> _gsDeflection;
131 PropertyObject<double> _gsDeflectionDeg;
132 PropertyObject<double> _gsDeflectionNorm;
135 /* ---------------------------------------------------------------- */
137 class NavRadioComponent {
139 NavRadioComponent( const std::string & name, SGPropertyNode_ptr rootNode );
140 virtual ~NavRadioComponent();
142 virtual void update( double dt, const SGGeod & aircraftPosition );
143 virtual void search( double frequency, const SGGeod & aircraftPosition );
144 virtual double getRange_nm( const SGGeod & aircraftPosition );
145 virtual void display( NavIndicator & navIndicator ) = 0;
146 virtual bool valid() const { return NULL != _navRecord && true == _serviceable; }
149 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
150 virtual FGNavList * getNavaidList() = 0;
152 // General-purpose sawtooth function. Graph looks like this:
155 // Odd symmetry, inversion symmetry about the origin.
156 // Unit slope at the origin.
157 // Max 1, min -1, period 4.
158 // Two zero-crossings per period, one with + slope, one with - slope.
159 // Useful for false localizer courses.
160 static double sawtooth(double xx)
162 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
165 SGPropertyNode_ptr _rootNode;
166 const std::string _name;
167 FGNavRecord * _navRecord;
168 PropertyObject<bool> _serviceable;
169 PropertyObject<double> _signalQuality_norm;
170 PropertyObject<double> _trueBearingTo_deg;
171 PropertyObject<double> _trueBearingFrom_deg;
172 PropertyObject<double> _trackDistance_m;
173 PropertyObject<double> _slantDistance_m;
174 PropertyObject<double> _heightAboveStation_ft;
175 PropertyObject<string> _ident;
176 PropertyObject<bool> _inRange;
177 PropertyObject<double> _range_nm;
180 class NavRadioComponentWithIdent : public NavRadioComponent {
182 NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent );
183 virtual ~NavRadioComponentWithIdent();
184 void update( double dt, const SGGeod & aircraftPosition );
186 static std::string getIdentString( const std::string & name, int index );
188 AudioIdent * _audioIdent;
189 PropertyObject<double> _identVolume;
190 PropertyObject<bool> _identEnabled;
193 std::string NavRadioComponentWithIdent::getIdentString( const std::string & name, int index )
195 std::ostringstream temp;
196 temp << name << "-ident-" << index;
200 NavRadioComponentWithIdent::NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent ) :
201 NavRadioComponent( name, rootNode ),
202 _audioIdent( audioIdent ),
203 _identVolume( rootNode->getNode(name,true)->getNode("ident-volume",true) ),
204 _identEnabled( rootNode->getNode(name,true)->getNode("ident-enabled",true) )
209 NavRadioComponentWithIdent::~NavRadioComponentWithIdent()
214 void NavRadioComponentWithIdent::update( double dt, const SGGeod & aircraftPosition )
216 NavRadioComponent::update( dt, aircraftPosition );
217 _audioIdent->update( dt );
219 if( false == ( valid() && _identEnabled && _signalQuality_norm > 0.1 ) ) {
220 _audioIdent->setIdent("", 0.0 );
223 _audioIdent->setIdent( _navRecord->get_trans_ident(), SGMiscd::clip(_identVolume, 0.0, 1.0) );
226 NavRadioComponent::NavRadioComponent( const std::string & name, SGPropertyNode_ptr rootNode ) :
230 _serviceable( rootNode->getNode(name,true)->getNode("serviceable",true) ),
231 _signalQuality_norm( rootNode->getNode(name,true)->getNode("signal-quality-norm",true) ),
232 _trueBearingTo_deg( rootNode->getNode(name,true)->getNode("true-bearing-to-deg",true) ),
233 _trueBearingFrom_deg( rootNode->getNode(name,true)->getNode("true-bearing-from-deg",true) ),
234 _trackDistance_m( rootNode->getNode(name,true)->getNode("track-distance-m",true) ),
235 _slantDistance_m( rootNode->getNode(name,true)->getNode("slant-distance-m",true) ),
236 _heightAboveStation_ft( rootNode->getNode(name,true)->getNode("height-above-station-ft",true) ),
237 _ident( rootNode->getNode(name,true)->getNode("ident",true) ),
238 _inRange( rootNode->getNode(name,true)->getNode("in-range",true) ),
239 _range_nm( rootNode->getNode(_name,true)->getNode("range-nm",true) )
241 simgear::props::Type typ = _serviceable.node()->getType();
242 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED))
246 NavRadioComponent::~NavRadioComponent()
250 double NavRadioComponent::getRange_nm( const SGGeod & aircraftPosition )
252 if( _navRecord == NULL ) return 0.0; // no station: no range
253 double d = _navRecord->get_range();
254 if( d <= SGLimitsd::min() ) return 25.0; // no configured range: arbitrary number
255 return d; // configured range
258 void NavRadioComponent::search( double frequency, const SGGeod & aircraftPosition )
260 if( NULL == (_navRecord = getNavaidList()->findByFreq(frequency, aircraftPosition )) ) {
261 SG_LOG(SG_INSTR,SG_ALERT, "No " << _name << " available at " << frequency );
265 SG_LOG(SG_INSTR,SG_ALERT, "Using " << _name << "'" << _navRecord->get_ident() << "' for " << frequency );
266 _ident = _navRecord->ident();
269 double NavRadioComponent::computeSignalQuality_norm( const SGGeod & aircraftPosition )
271 if( false == valid() ) return 0.0;
273 double distance_nm = _slantDistance_m * SG_METER_TO_NM;
274 double range_nm = _range_nm;
276 // assume signal quality is 100% up to the published range and
277 // decay with the distance squared further out
278 if ( distance_nm <= range_nm ) return 1.0;
279 return range_nm*range_nm/(distance_nm*distance_nm);
282 void NavRadioComponent::update( double dt, const SGGeod & aircraftPosition )
284 if( false == valid() ) {
285 _signalQuality_norm = 0.0;
286 _trueBearingTo_deg = 0.0;
287 _trueBearingFrom_deg = 0.0;
288 _trackDistance_m = 0.0;
289 _slantDistance_m = 0.0;
293 _slantDistance_m = dist(_navRecord->cart(), SGVec3d::fromGeod(aircraftPosition));
295 double az1 = 0.0, az2 = 0.0, dist = 0.0;
296 SGGeodesy::inverse(aircraftPosition, _navRecord->geod(), az1, az2, dist );
297 _trueBearingTo_deg = az1; _trueBearingFrom_deg = az2; _trackDistance_m = dist;
298 _heightAboveStation_ft = SGMiscd::max(0.0, aircraftPosition.getElevationFt() - _navRecord->get_elev_ft());
300 _range_nm = getRange_nm(aircraftPosition);
301 _signalQuality_norm = computeSignalQuality_norm( aircraftPosition );
302 _inRange = _signalQuality_norm > 0.2;
305 /* ---------------------------------------------------------------- */
307 static std::string VORTablePath( const char * name )
309 SGPath path( globals->get_fg_root() );
310 path.append( "Navaids" );
315 class VOR : public NavRadioComponentWithIdent {
317 VOR( SGPropertyNode_ptr rootNode);
319 virtual void update( double dt, const SGGeod & aircraftPosition );
320 virtual void display( NavIndicator & navIndicator );
321 virtual double getRange_nm(const SGGeod & aircraftPosition);
323 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
324 virtual FGNavList * getNavaidList();
328 class ServiceVolume {
331 term_tbl(VORTablePath("range.term")),
332 low_tbl(VORTablePath("range.low")),
333 high_tbl(VORTablePath("range.high")) {
335 double adjustRange( double height_ft, double nominalRange_nm );
338 SGInterpTable term_tbl;
339 SGInterpTable low_tbl;
340 SGInterpTable high_tbl;
343 PropertyObject<double> _radial;
344 PropertyObject<double> _radialInbound;
347 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
348 double VOR::ServiceVolume::adjustRange( double height_ft, double nominalRange_nm )
350 if (nominalRange_nm < SGLimitsd::min() )
351 nominalRange_nm = FG_NAV_DEFAULT_RANGE;
353 // extend out actual usable range to be 1.3x the published safe range
354 const double usability_factor = 1.3;
356 // assumptions we model the standard service volume, plus
357 // ... rather than specifying a cylinder, we model a cone that
358 // contains the cylinder. Then we put an upside down cone on top
359 // to model diminishing returns at too-high altitudes.
361 if ( nominalRange_nm < 25.0 + SG_EPSILON ) {
362 // Standard Terminal Service Volume
363 return term_tbl.interpolate( height_ft ) * usability_factor;
364 } else if ( nominalRange_nm < 50.0 + SG_EPSILON ) {
365 // Standard Low Altitude Service Volume
366 // table is based on range of 40, scale to actual range
367 return low_tbl.interpolate( height_ft ) * nominalRange_nm / 40.0
370 // Standard High Altitude Service Volume
371 // table is based on range of 130, scale to actual range
372 return high_tbl.interpolate( height_ft ) * nominalRange_nm / 130.0
377 VOR::VOR( SGPropertyNode_ptr rootNode) :
378 NavRadioComponentWithIdent("vor", rootNode, new VORAudioIdent(getIdentString(string("vor"), rootNode->getIndex()))),
380 _radial( rootNode->getNode(_name,true)->getNode("radial",true) ),
381 _radialInbound( rootNode->getNode(_name,true)->getNode("radial-inbound",true) )
389 double VOR::getRange_nm( const SGGeod & aircraftPosition )
391 return _serviceVolume.adjustRange( _heightAboveStation_ft, _navRecord->get_range() );
394 FGNavList * VOR::getNavaidList()
396 return globals->get_navlist();
399 double VOR::computeSignalQuality_norm( const SGGeod & aircraftPosition )
401 // apply cone of confusion. Some sources say it's opening angle is 53deg, others estimate
402 // a diameter of 1NM per 6000ft (approx. 45deg). ICAO Annex 10 says minimum 40deg.
403 // We use 1NM@6000ft and a distance-squared
404 // function to make signal-quality=100% 0.5NM@6000ft from the center and zero overhead
405 double cone_of_confusion_width = 0.5 * _heightAboveStation_ft / 6000.0 * SG_NM_TO_METER;
406 if( _trackDistance_m < cone_of_confusion_width ) {
407 double d = cone_of_confusion_width <= SGLimitsd::min() ? 1 :
408 (1 - _trackDistance_m/cone_of_confusion_width);
412 // use default decay function outside the cone of confusion
413 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
416 void VOR::update( double dt, const SGGeod & aircraftPosition )
419 NavRadioComponentWithIdent::update( dt, aircraftPosition );
421 if( false == valid() ) {
426 // an arbitrary error function
427 double error = 0.5*(sin(_totalTime/11.0) + sin(_totalTime/23.0));
429 // add 1% error at 100% signal-quality
430 // add 50% error at 0% signal-quality
431 // of full deflection (+/-10deg)
432 double e = 10.0 * ( 0.01 + (1-_signalQuality_norm) * 0.49 ) * error;
434 // compute magnetic bearing from the station (aka current radial)
435 double r = SGMiscd::normalizePeriodic(0.0, 360.0, _trueBearingFrom_deg - _navRecord->get_multiuse() + e );
438 _radialInbound = SGMiscd::normalizePeriodic(0.0,360.0, 180.0 + _radial);
441 void VOR::display( NavIndicator & navIndicator )
443 if( false == valid() ) return;
445 double offset = SGMiscd::normalizePeriodic(-180.0,180.0,_radial - navIndicator.getSelectedCourse());
446 bool to = fabs(offset) >= 90.0;
448 if( to ) offset = -offset + copysign(180.0,offset);
450 navIndicator.showTo( to );
451 navIndicator.showFrom( !to );
452 // normalize to +/- 1.0 for +/- 10deg, decrease deflection with decreasing signal
453 navIndicator.setCDI( SGMiscd::clip( -offset/10.0, -1.0, 1.0 ) * _signalQuality_norm );
454 navIndicator.setSignalQuality( _signalQuality_norm );
457 /* ---------------------------------------------------------------- */
458 class LOC : public NavRadioComponentWithIdent {
460 LOC( SGPropertyNode_ptr rootNode );
462 virtual void update( double dt, const SGGeod & aircraftPosition );
463 virtual void search( double frequency, const SGGeod & aircraftPosition );
464 virtual void display( NavIndicator & navIndicator );
465 virtual double getRange_nm(const SGGeod & aircraftPosition);
468 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
469 virtual FGNavList * getNavaidList();
472 class ServiceVolume {
475 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
477 SGInterpTable _azimuthTable;
478 SGInterpTable _elevationTable;
480 PropertyObject<double> _localizerOffset_norm;
481 PropertyObject<double> _localizerWidth_deg;
484 LOC::ServiceVolume::ServiceVolume()
486 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
487 // ICAO Annex 10 - 3.1.3.2.2: The emission from the localizer
488 // shall be horizontally polarized
489 // very rough abstraction of a 5-element yagi antenna's
490 // E-plane radiation diagram
491 _azimuthTable.addEntry( 0.0, 1.0 );
492 _azimuthTable.addEntry( 10.0, 1.0 );
493 _azimuthTable.addEntry( 30.0, 0.75 );
494 _azimuthTable.addEntry( 40.0, 0.50 );
495 _azimuthTable.addEntry( 50.0, 0.20 );
496 _azimuthTable.addEntry( 60.0, 0.10 );
497 _azimuthTable.addEntry( 70.0, 0.20 );
498 _azimuthTable.addEntry( 80.0, 0.10 );
499 _azimuthTable.addEntry( 90.0, 0.05 );
500 _azimuthTable.addEntry( 105.0, 0.10 );
501 _azimuthTable.addEntry( 130.0, 0.05 );
502 _azimuthTable.addEntry( 150.0, 0.30 );
503 _azimuthTable.addEntry( 160.0, 0.40 );
504 _azimuthTable.addEntry( 170.0, 0.50 );
505 _azimuthTable.addEntry( 180.0, 0.50 );
507 _elevationTable.addEntry( 0.0, 0.1 );
508 _elevationTable.addEntry( 1.05, 1.0 );
509 _elevationTable.addEntry( 7.00, 1.0 );
510 _elevationTable.addEntry( 45.0, 0.3 );
511 _elevationTable.addEntry( 90.0, 0.1 );
512 _elevationTable.addEntry( 180.0, 0.01 );
515 double LOC::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
517 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
518 _elevationTable.interpolate( fabs(elevationAngle_deg) );
521 LOC::LOC( SGPropertyNode_ptr rootNode) :
522 NavRadioComponentWithIdent("loc", rootNode, new LOCAudioIdent(getIdentString(string("loc"), rootNode->getIndex()))),
524 _localizerOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
525 _localizerWidth_deg( rootNode->getNode(_name,true)->getNode("width-deg",true) )
533 FGNavList * LOC::getNavaidList()
535 return globals->get_loclist();
538 void LOC::search( double frequency, const SGGeod & aircraftPosition )
540 NavRadioComponentWithIdent::search( frequency, aircraftPosition );
541 if( false == valid() ) {
542 _localizerWidth_deg = 0.0;
546 // cache slightly expensive value,
547 // sanitized in FGNavRecord::localizerWidth() to never become zero
548 _localizerWidth_deg = _navRecord->localizerWidth();
551 /* Localizer coverage (ICAO Annex 10 Volume I 3.1.3.3
552 25NM within +/-10 deg from the front course line
553 17NM between 10 and 35deg from the front course line
554 10NM outside of +/- 35deg if coverage is provided
555 at and above a height of 2000ft above threshold or
556 1000ft above the highest point within intermediate
557 and final approach areas. Upper limit is a surface
558 extending outward from the localizer and inclined at
559 7 degrees above the horizontal
561 double LOC::getRange_nm(const SGGeod & aircraftPosition)
563 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
564 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
566 // looks like our navrecord declared range is based on 10NM?
567 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
570 double LOC::computeSignalQuality_norm( const SGGeod & aircraftPosition )
572 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
575 void LOC::update( double dt, const SGGeod & aircraftPosition )
577 NavRadioComponentWithIdent::update( dt, aircraftPosition );
579 if( false == valid() ) {
580 _localizerOffset_norm = 0.0;
584 double offset = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
586 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
587 // zeros i.e. six courses: one front course, one back course, and four
588 // false courses. Three of the six are reverse sensing.
589 offset = 30.0 * sawtooth(offset / 30.0);
591 // normalize offset to the localizer width, scale and clip to [-1..1]
592 offset = SGMiscd::clip( 2.0 * offset / _localizerWidth_deg, -1.0, 1.0 );
594 _localizerOffset_norm = offset;
597 void LOC::display( NavIndicator & navIndicator )
599 if( false == valid() )
602 navIndicator.showTo( true );
603 navIndicator.showFrom( false );
605 navIndicator.setCDI( _localizerOffset_norm * _signalQuality_norm );
606 navIndicator.setSignalQuality( _signalQuality_norm );
609 class GS : public NavRadioComponent {
611 GS( SGPropertyNode_ptr rootNode);
613 virtual void update( double dt, const SGGeod & aircraftPosition );
614 virtual void search( double frequency, const SGGeod & aircraftPosition );
615 virtual void display( NavIndicator & navIndicator );
617 virtual double getRange_nm(const SGGeod & aircraftPosition);
619 virtual FGNavList * getNavaidList();
622 class ServiceVolume {
625 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
627 SGInterpTable _azimuthTable;
628 SGInterpTable _elevationTable;
630 static SGVec3d tangentVector(const SGGeod& midpoint, const double heading);
632 PropertyObject<double> _targetGlideslope_deg;
633 PropertyObject<double> _glideslopeOffset_norm;
638 GS::ServiceVolume::ServiceVolume()
640 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
641 // ICAO Annex 10 - 3.1.5.2.2: The emission from the glide path equipment
642 // shall be horizontally polarized
643 // very rough abstraction of a 5-element yagi antenna's
644 // E-plane radiation diagram
645 _azimuthTable.addEntry( 0.0, 1.0 );
646 _azimuthTable.addEntry( 10.0, 1.0 );
647 _azimuthTable.addEntry( 30.0, 0.75 );
648 _azimuthTable.addEntry( 40.0, 0.50 );
649 _azimuthTable.addEntry( 50.0, 0.20 );
650 _azimuthTable.addEntry( 60.0, 0.10 );
651 _azimuthTable.addEntry( 70.0, 0.20 );
652 _azimuthTable.addEntry( 80.0, 0.10 );
653 _azimuthTable.addEntry( 90.0, 0.05 );
654 _azimuthTable.addEntry( 105.0, 0.10 );
655 _azimuthTable.addEntry( 130.0, 0.05 );
656 _azimuthTable.addEntry( 150.0, 0.30 );
657 _azimuthTable.addEntry( 160.0, 0.40 );
658 _azimuthTable.addEntry( 170.0, 0.50 );
659 _azimuthTable.addEntry( 180.0, 0.50 );
661 _elevationTable.addEntry( 0.0, 0.1 );
662 _elevationTable.addEntry( 1.05, 1.0 );
663 _elevationTable.addEntry( 7.00, 1.0 );
664 _elevationTable.addEntry( 45.0, 0.3 );
665 _elevationTable.addEntry( 90.0, 0.1 );
666 _elevationTable.addEntry( 180.0, 0.01 );
669 double GS::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
671 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
672 _elevationTable.interpolate( fabs(elevationAngle_deg) );
675 GS::GS( SGPropertyNode_ptr rootNode) :
676 NavRadioComponent("gs", rootNode ),
677 _targetGlideslope_deg( rootNode->getNode(_name,true)->getNode("slope",true) ),
678 _glideslopeOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
679 _gsAxis(SGVec3d::zeros()),
680 _gsVertical(SGVec3d::zeros())
688 FGNavList * GS::getNavaidList()
690 return globals->get_gslist();
693 double GS::getRange_nm(const SGGeod & aircraftPosition)
695 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
696 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - fmod(_navRecord->get_multiuse(), 1000.0) );
697 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
700 // Calculate a Cartesian unit vector in the
701 // local horizontal plane, i.e. tangent to the
702 // surface of the earth at the local ground zero.
703 // The tangent vector passes through the given <midpoint>
704 // and points forward along the given <heading>.
705 // The <heading> is given in degrees.
706 SGVec3d GS::tangentVector(const SGGeod& midpoint, const double heading)
708 // move 100m away from the midpoint - arbitrary number
709 const double delta(100.0);
711 double az2; // ignored
712 SGGeodesy::direct(midpoint, heading, delta, head, az2);
713 SGGeodesy::direct(midpoint, 180+heading, delta, tail, az2);
714 head.setElevationM(midpoint.getElevationM());
715 tail.setElevationM(midpoint.getElevationM());
716 SGVec3d head_xyz = SGVec3d::fromGeod(head);
717 SGVec3d tail_xyz = SGVec3d::fromGeod(tail);
718 // Awkward formula here, needed because vector-by-scalar
719 // multiplication is defined, but not vector-by-scalar division.
720 return (head_xyz - tail_xyz) * (0.5/delta);
723 void GS::search( double frequency, const SGGeod & aircraftPosition )
725 NavRadioComponent::search( frequency, aircraftPosition );
726 if( false == valid() ) {
727 _gsAxis = SGVec3d::zeros();
728 _gsVertical = SGVec3d::zeros();
729 _targetGlideslope_deg = 3.0;
733 double gs_radial = SGMiscd::normalizePeriodic(0.0, 360.0, fmod(_navRecord->get_multiuse(), 1000.0) );
735 _gsAxis = tangentVector(_navRecord->geod(), gs_radial);
736 SGVec3d gsBaseline = tangentVector(_navRecord->geod(), gs_radial + 90.0);
737 _gsVertical = cross(gsBaseline, _gsAxis);
739 int tmp = (int)(_navRecord->get_multiuse() / 1000.0);
740 // catch unconfigured glideslopes here, they will cause nan later
741 _targetGlideslope_deg = SGMiscd::max( 1.0, (double)tmp / 100.0 );
744 void GS::update( double dt, const SGGeod & aircraftPosition )
746 NavRadioComponent::update( dt, aircraftPosition );
747 if( false == valid() ) {
748 _glideslopeOffset_norm = 0.0;
752 SGVec3d pos = SGVec3d::fromGeod(aircraftPosition) - _navRecord->cart(); // relative vector from gs antenna to aircraft
753 // The positive GS axis points along the runway in the landing direction,
754 // toward the far end, not toward the approach area, so we need a - sign here:
755 double comp_h = -dot(pos, _gsAxis); // component in horiz direction
756 double comp_v = dot(pos, _gsVertical); // component in vertical direction
757 //double comp_b = dot(pos, _gsBaseline); // component in baseline direction
758 //if (comp_b) {} // ... (useful for debugging)
760 // _gsDirect represents the angle of elevation of the aircraft
761 // as seen by the GS transmitter.
762 double gsDirect = atan2(comp_v, comp_h) * SGD_RADIANS_TO_DEGREES;
763 // At this point, if the aircraft is centered on the glide slope,
764 // _gsDirect will be a small positive number, e.g. 3.0 degrees
766 // Aim the branch cut straight down
767 // into the ground below the GS transmitter:
768 if (gsDirect < -90.0) gsDirect += 360.0;
770 double offset = _targetGlideslope_deg - gsDirect;
772 offset = _targetGlideslope_deg/2 * sawtooth(2.0*offset/_targetGlideslope_deg);
773 assert( false == isnan(offset) );
774 // GS is documented to be 1.4 degrees thick,
775 // i.e. plus or minus 0.7 degrees from the midline:
776 _glideslopeOffset_norm = SGMiscd::clip(offset/0.7, -1.0, 1.0);
779 void GS::display( NavIndicator & navIndicator )
781 if( false == valid() ) {
782 navIndicator.setGS( false );
785 navIndicator.setGS( true );
786 navIndicator.setGS( _glideslopeOffset_norm );
789 /* ------------- A NAV/COMM Frequency formatter ---------------------- */
791 class FrequencyFormatter : public SGPropertyChangeListener {
793 FrequencyFormatter( SGPropertyNode_ptr freqNode, SGPropertyNode_ptr fmtFreqNode, double channelSpacing ) :
794 _freqNode( freqNode ),
795 _fmtFreqNode( fmtFreqNode ),
796 _channelSpacing(channelSpacing)
798 _freqNode->addChangeListener( this );
799 valueChanged(_freqNode);
801 ~FrequencyFormatter()
803 _freqNode->removeChangeListener( this );
806 void valueChanged (SGPropertyNode * prop)
808 // format as fixed decimal "nnn.nn"
813 << std::setprecision(2)
815 _fmtFreqNode->setStringValue( buf.str() );
818 double getFrequency() const
820 double d = SGMiscd::roundToInt(_freqNode->getDoubleValue() / _channelSpacing) * _channelSpacing;
821 // strip last digit, do not round
822 return ((int)(d*100))/100.0;
826 SGPropertyNode_ptr _freqNode;
827 SGPropertyNode_ptr _fmtFreqNode;
828 double _channelSpacing;
832 /* ------------- The NavRadio implementation ---------------------- */
834 class NavRadioImpl : public NavRadio {
836 NavRadioImpl( SGPropertyNode_ptr node );
837 virtual ~NavRadioImpl();
839 virtual void update( double dt );
846 Legacy( NavRadioImpl * navRadioImpl ) : _navRadioImpl( navRadioImpl ) {}
849 void update( double dt );
851 NavRadioImpl * _navRadioImpl;
852 SGPropertyNode_ptr is_valid_node;
853 SGPropertyNode_ptr nav_serviceable_node;
856 const static int VOR_COMPONENT = 0;
857 const static int LOC_COMPONENT = 1;
858 const static int GS_COMPONENT = 2;
862 SGPropertyNode_ptr _rootNode;
863 FrequencyFormatter _useFrequencyFormatter;
864 FrequencyFormatter _stbyFrequencyFormatter;
865 std::vector<NavRadioComponent*> _components;
866 NavIndicator _navIndicator;
869 PropertyObject<bool> _cdiDisconnected;
872 NavRadioImpl::NavRadioImpl( SGPropertyNode_ptr node ) :
874 _name(node->getStringValue("name", "nav")),
875 _num(node->getIntValue("number", 0)),
876 _rootNode(fgGetNode( string("/instrumentation/") + _name, _num, true)),
877 _useFrequencyFormatter( _rootNode->getNode("frequencies/selected-mhz",true), _rootNode->getNode("frequencies/selected-mhz-fmt",true), 0.05 ),
878 _stbyFrequencyFormatter( _rootNode->getNode("frequencies/standby-mhz",true), _rootNode->getNode("frequencies/standby-mhz-fmt",true), 0.05 ),
879 _navIndicator(_rootNode),
882 _cdiDisconnected(_rootNode->getNode("cdi-disconnected",true))
886 NavRadioImpl::~NavRadioImpl()
888 BOOST_FOREACH( NavRadioComponent * p, _components ) {
893 void NavRadioImpl::init()
895 if( 0 < _components.size() )
898 _components.push_back( new VOR(_rootNode) );
899 _components.push_back( new LOC(_rootNode) );
900 _components.push_back( new GS(_rootNode) );
905 void NavRadioImpl::search()
909 void NavRadioImpl::update( double dt )
911 if( dt < SGLimitsd::min() ) return;
916 position = globals->get_aircraft_position();
918 catch( exception & ) {
923 if( _frequency != _useFrequencyFormatter.getFrequency() ) {
924 _frequency = _useFrequencyFormatter.getFrequency();
928 BOOST_FOREACH( NavRadioComponent * p, _components ) {
929 if( _stationTTL <= 0.0 )
930 p->search( _frequency, position );
931 p->update( dt, position );
933 if( false == _cdiDisconnected )
934 p->display( _navIndicator );
937 if( _stationTTL <= 0.0 )
943 void NavRadioImpl::Legacy::init()
945 is_valid_node = _navRadioImpl->_rootNode->getChild("data-is-valid", 0, true);
946 nav_serviceable_node = _navRadioImpl->_rootNode->getChild("serviceable", 0, true);
950 void NavRadioImpl::Legacy::update( double dt )
952 is_valid_node->setBoolValue(
953 _navRadioImpl->_components[VOR_COMPONENT]->valid() || _navRadioImpl->_components[LOC_COMPONENT]->valid()
958 SGSubsystem * NavRadio::createInstance( SGPropertyNode_ptr rootNode )
960 // use old navradio code by default
961 if( fgGetBool( "/instrumentation/use-new-navradio", false ) )
962 return new NavRadioImpl( rootNode );
964 return new FGNavRadio( rootNode );
967 } // namespace Instrumentation