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 - 2011 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>
36 #include <simgear/misc/strutils.hxx>
38 #include <Main/fg_props.hxx>
39 #include <Navaids/navlist.hxx>
40 #include <Sound/audioident.hxx>
42 #include "navradio.hxx"
45 namespace Instrumentation {
47 using simgear::PropertyObject;
49 /* --------------The Navigation Indicator ----------------------------- */
53 NavIndicator( SGPropertyNode * rootNode ) :
54 _cdi( rootNode->getNode("heading-needle-deflection", true ) ),
55 _cdiNorm( rootNode->getNode("heading-needle-deflection-norm", true ) ),
56 _course( rootNode->getNode("radials/selected-deg", true ) ),
57 _toFlag( rootNode->getNode("to-flag", true ) ),
58 _fromFlag( rootNode->getNode("from-flag", true ) ),
59 _signalQuality( rootNode->getNode("signal-quality-norm", true ) ),
60 _hasGS( rootNode->getNode("has-gs", true ) ),
61 _gsDeflection(rootNode->getNode("gs-needle-deflection", true )),
62 _gsDeflectionDeg(rootNode->getNode("gs-needle-deflection-deg", true )),
63 _gsDeflectionNorm(rootNode->getNode("gs-needle-deflection-norm", true ))
67 virtual ~NavIndicator() {}
70 * set the normalized CDI deflection
71 * @param norm the cdi deflection normalized [-1..1]
73 void setCDI( double norm )
80 * set the normalized GS deflection
81 * @param norm the gs deflection normalized to [-1..1]
83 void setGS( double norm )
85 _gsDeflectionNorm = norm;
86 _gsDeflectionDeg = norm * 0.7;
87 _gsDeflection = norm * 3.5;
90 void setGS( bool enabled )
98 void showFrom( bool on )
103 void showTo( bool on )
108 void setSelectedCourse( double course )
113 double getSelectedCourse() const
115 return SGMiscd::normalizePeriodic(0.0, 360.0, _course );
118 void setSignalQuality( double signalQuality )
120 _signalQuality = signalQuality;
124 PropertyObject<double> _cdi;
125 PropertyObject<double> _cdiNorm;
126 PropertyObject<double> _course;
127 PropertyObject<double> _toFlag;
128 PropertyObject<double> _fromFlag;
129 PropertyObject<double> _signalQuality;
130 PropertyObject<double> _hasGS;
131 PropertyObject<double> _gsDeflection;
132 PropertyObject<double> _gsDeflectionDeg;
133 PropertyObject<double> _gsDeflectionNorm;
136 /* ---------------------------------------------------------------- */
138 class NavRadioComponent {
140 NavRadioComponent( const std::string & name, SGPropertyNode_ptr rootNode );
141 virtual ~NavRadioComponent();
143 virtual void update( double dt, const SGGeod & aircraftPosition );
144 virtual void search( double frequency, const SGGeod & aircraftPosition );
145 virtual double getRange_nm( const SGGeod & aircraftPosition );
146 virtual void display( NavIndicator & navIndicator ) = 0;
147 virtual bool valid() const { return NULL != _navRecord && true == _serviceable; }
148 virtual const std::string getIdent() const { return _ident; }
151 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
152 virtual FGNavList * getNavaidList() = 0;
154 // General-purpose sawtooth function. Graph looks like this:
157 // Odd symmetry, inversion symmetry about the origin.
158 // Unit slope at the origin.
159 // Max 1, min -1, period 4.
160 // Two zero-crossings per period, one with + slope, one with - slope.
161 // Useful for false localizer courses.
162 static double sawtooth(double xx)
164 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
167 SGPropertyNode_ptr _rootNode;
168 const std::string _name;
169 FGNavRecord * _navRecord;
170 PropertyObject<bool> _serviceable;
171 PropertyObject<double> _signalQuality_norm;
172 PropertyObject<double> _trueBearingTo_deg;
173 PropertyObject<double> _trueBearingFrom_deg;
174 PropertyObject<double> _trackDistance_m;
175 PropertyObject<double> _slantDistance_m;
176 PropertyObject<double> _heightAboveStation_ft;
177 PropertyObject<string> _ident;
178 PropertyObject<bool> _inRange;
179 PropertyObject<double> _range_nm;
182 class NavRadioComponentWithIdent : public NavRadioComponent {
184 NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent );
185 virtual ~NavRadioComponentWithIdent();
186 void update( double dt, const SGGeod & aircraftPosition );
188 static std::string getIdentString( const std::string & name, int index );
190 AudioIdent * _audioIdent;
191 PropertyObject<double> _identVolume;
192 PropertyObject<bool> _identEnabled;
195 std::string NavRadioComponentWithIdent::getIdentString( const std::string & name, int index )
197 std::ostringstream temp;
198 temp << name << "-ident-" << index;
202 NavRadioComponentWithIdent::NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent ) :
203 NavRadioComponent( name, rootNode ),
204 _audioIdent( audioIdent ),
205 _identVolume( rootNode->getNode(name,true)->getNode("ident-volume",true) ),
206 _identEnabled( rootNode->getNode(name,true)->getNode("ident-enabled",true) )
211 NavRadioComponentWithIdent::~NavRadioComponentWithIdent()
216 void NavRadioComponentWithIdent::update( double dt, const SGGeod & aircraftPosition )
218 NavRadioComponent::update( dt, aircraftPosition );
219 _audioIdent->update( dt );
221 if( false == ( valid() && _identEnabled && _signalQuality_norm > 0.1 ) ) {
222 _audioIdent->setIdent("", 0.0 );
225 _audioIdent->setIdent( _ident, SGMiscd::clip(_identVolume, 0.0, 1.0) );
228 NavRadioComponent::NavRadioComponent( const std::string & name, SGPropertyNode_ptr rootNode ) :
232 _serviceable( rootNode->getNode(name,true)->getNode("serviceable",true) ),
233 _signalQuality_norm( rootNode->getNode(name,true)->getNode("signal-quality-norm",true) ),
234 _trueBearingTo_deg( rootNode->getNode(name,true)->getNode("true-bearing-to-deg",true) ),
235 _trueBearingFrom_deg( rootNode->getNode(name,true)->getNode("true-bearing-from-deg",true) ),
236 _trackDistance_m( rootNode->getNode(name,true)->getNode("track-distance-m",true) ),
237 _slantDistance_m( rootNode->getNode(name,true)->getNode("slant-distance-m",true) ),
238 _heightAboveStation_ft( rootNode->getNode(name,true)->getNode("height-above-station-ft",true) ),
239 _ident( rootNode->getNode(name,true)->getNode("ident",true) ),
240 _inRange( rootNode->getNode(name,true)->getNode("in-range",true) ),
241 _range_nm( rootNode->getNode(_name,true)->getNode("range-nm",true) )
243 simgear::props::Type typ = _serviceable.node()->getType();
244 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED))
248 NavRadioComponent::~NavRadioComponent()
252 double NavRadioComponent::getRange_nm( const SGGeod & aircraftPosition )
254 if( _navRecord == NULL ) return 0.0; // no station: no range
255 double d = _navRecord->get_range();
256 if( d <= SGLimitsd::min() ) return 25.0; // no configured range: arbitrary number
257 return d; // configured range
260 void NavRadioComponent::search( double frequency, const SGGeod & aircraftPosition )
262 if( NULL == (_navRecord = getNavaidList()->findByFreq(frequency, aircraftPosition )) ) {
263 SG_LOG(SG_INSTR,SG_ALERT, "No " << _name << " available at " << frequency );
267 SG_LOG(SG_INSTR,SG_ALERT, "Using " << _name << "'" << _navRecord->get_ident() << "' for " << frequency );
268 _ident = _navRecord->ident();
271 double NavRadioComponent::computeSignalQuality_norm( const SGGeod & aircraftPosition )
273 if( false == valid() ) return 0.0;
275 double distance_nm = _slantDistance_m * SG_METER_TO_NM;
276 double range_nm = _range_nm;
278 // assume signal quality is 100% up to the published range and
279 // decay with the distance squared further out
280 if ( distance_nm <= range_nm ) return 1.0;
281 return range_nm*range_nm/(distance_nm*distance_nm);
284 void NavRadioComponent::update( double dt, const SGGeod & aircraftPosition )
286 if( false == valid() ) {
287 _signalQuality_norm = 0.0;
288 _trueBearingTo_deg = 0.0;
289 _trueBearingFrom_deg = 0.0;
290 _trackDistance_m = 0.0;
291 _slantDistance_m = 0.0;
295 _slantDistance_m = dist(_navRecord->cart(), SGVec3d::fromGeod(aircraftPosition));
297 double az1 = 0.0, az2 = 0.0, dist = 0.0;
298 SGGeodesy::inverse(aircraftPosition, _navRecord->geod(), az1, az2, dist );
299 _trueBearingTo_deg = az1; _trueBearingFrom_deg = az2; _trackDistance_m = dist;
300 _heightAboveStation_ft = SGMiscd::max(0.0, aircraftPosition.getElevationFt() - _navRecord->get_elev_ft());
302 _range_nm = getRange_nm(aircraftPosition);
303 _signalQuality_norm = computeSignalQuality_norm( aircraftPosition );
304 _inRange = _signalQuality_norm > 0.2;
307 /* ---------------------------------------------------------------- */
309 static std::string VORTablePath( const char * name )
311 SGPath path( globals->get_fg_root() );
312 path.append( "Navaids" );
317 class VOR : public NavRadioComponentWithIdent {
319 VOR( SGPropertyNode_ptr rootNode);
321 virtual void update( double dt, const SGGeod & aircraftPosition );
322 virtual void display( NavIndicator & navIndicator );
323 virtual double getRange_nm(const SGGeod & aircraftPosition);
325 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
326 virtual FGNavList * getNavaidList();
330 class ServiceVolume {
333 term_tbl(VORTablePath("range.term")),
334 low_tbl(VORTablePath("range.low")),
335 high_tbl(VORTablePath("range.high")) {
337 double adjustRange( double height_ft, double nominalRange_nm );
340 SGInterpTable term_tbl;
341 SGInterpTable low_tbl;
342 SGInterpTable high_tbl;
345 PropertyObject<double> _radial;
346 PropertyObject<double> _radialInbound;
349 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
350 double VOR::ServiceVolume::adjustRange( double height_ft, double nominalRange_nm )
352 if (nominalRange_nm < SGLimitsd::min() )
353 nominalRange_nm = FG_NAV_DEFAULT_RANGE;
355 // extend out actual usable range to be 1.3x the published safe range
356 const double usability_factor = 1.3;
358 // assumptions we model the standard service volume, plus
359 // ... rather than specifying a cylinder, we model a cone that
360 // contains the cylinder. Then we put an upside down cone on top
361 // to model diminishing returns at too-high altitudes.
363 if ( nominalRange_nm < 25.0 + SG_EPSILON ) {
364 // Standard Terminal Service Volume
365 return term_tbl.interpolate( height_ft ) * usability_factor;
366 } else if ( nominalRange_nm < 50.0 + SG_EPSILON ) {
367 // Standard Low Altitude Service Volume
368 // table is based on range of 40, scale to actual range
369 return low_tbl.interpolate( height_ft ) * nominalRange_nm / 40.0
372 // Standard High Altitude Service Volume
373 // table is based on range of 130, scale to actual range
374 return high_tbl.interpolate( height_ft ) * nominalRange_nm / 130.0
379 VOR::VOR( SGPropertyNode_ptr rootNode) :
380 NavRadioComponentWithIdent("vor", rootNode, new VORAudioIdent(getIdentString(string("vor"), rootNode->getIndex()))),
382 _radial( rootNode->getNode(_name,true)->getNode("radial",true) ),
383 _radialInbound( rootNode->getNode(_name,true)->getNode("radial-inbound",true) )
391 double VOR::getRange_nm( const SGGeod & aircraftPosition )
393 return _serviceVolume.adjustRange( _heightAboveStation_ft, _navRecord->get_range() );
396 FGNavList * VOR::getNavaidList()
398 return globals->get_navlist();
401 double VOR::computeSignalQuality_norm( const SGGeod & aircraftPosition )
403 // apply cone of confusion. Some sources say it's opening angle is 53deg, others estimate
404 // a diameter of 1NM per 6000ft (approx. 45deg). ICAO Annex 10 says minimum 40deg.
405 // We use 1NM@6000ft and a distance-squared
406 // function to make signal-quality=100% 0.5NM@6000ft from the center and zero overhead
407 double cone_of_confusion_width = 0.5 * _heightAboveStation_ft / 6000.0 * SG_NM_TO_METER;
408 if( _trackDistance_m < cone_of_confusion_width ) {
409 double d = cone_of_confusion_width <= SGLimitsd::min() ? 1 :
410 (1 - _trackDistance_m/cone_of_confusion_width);
414 // use default decay function outside the cone of confusion
415 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
418 void VOR::update( double dt, const SGGeod & aircraftPosition )
421 NavRadioComponentWithIdent::update( dt, aircraftPosition );
423 if( false == valid() ) {
428 // an arbitrary error function
429 double error = 0.5*(sin(_totalTime/11.0) + sin(_totalTime/23.0));
431 // add 1% error at 100% signal-quality
432 // add 50% error at 0% signal-quality
433 // of full deflection (+/-10deg)
434 double e = 10.0 * ( 0.01 + (1-_signalQuality_norm) * 0.49 ) * error;
436 // compute magnetic bearing from the station (aka current radial)
437 double r = SGMiscd::normalizePeriodic(0.0, 360.0, _trueBearingFrom_deg - _navRecord->get_multiuse() + e );
440 _radialInbound = SGMiscd::normalizePeriodic(0.0,360.0, 180.0 + _radial);
443 void VOR::display( NavIndicator & navIndicator )
445 if( false == valid() ) return;
447 double offset = SGMiscd::normalizePeriodic(-180.0,180.0,_radial - navIndicator.getSelectedCourse());
448 bool to = fabs(offset) >= 90.0;
450 if( to ) offset = -offset + copysign(180.0,offset);
452 navIndicator.showTo( to );
453 navIndicator.showFrom( !to );
454 // normalize to +/- 1.0 for +/- 10deg, decrease deflection with decreasing signal
455 navIndicator.setCDI( SGMiscd::clip( -offset/10.0, -1.0, 1.0 ) * _signalQuality_norm );
456 navIndicator.setSignalQuality( _signalQuality_norm );
459 /* ---------------------------------------------------------------- */
460 class LOC : public NavRadioComponentWithIdent {
462 LOC( SGPropertyNode_ptr rootNode );
464 virtual void update( double dt, const SGGeod & aircraftPosition );
465 virtual void search( double frequency, const SGGeod & aircraftPosition );
466 virtual void display( NavIndicator & navIndicator );
467 virtual double getRange_nm(const SGGeod & aircraftPosition);
470 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
471 virtual FGNavList * getNavaidList();
474 class ServiceVolume {
477 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
479 SGInterpTable _azimuthTable;
480 SGInterpTable _elevationTable;
482 PropertyObject<double> _localizerOffset_norm;
483 PropertyObject<double> _localizerWidth_deg;
486 LOC::ServiceVolume::ServiceVolume()
488 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
489 // ICAO Annex 10 - 3.1.3.2.2: The emission from the localizer
490 // shall be horizontally polarized
491 // very rough abstraction of a 5-element yagi antenna's
492 // E-plane radiation diagram
493 _azimuthTable.addEntry( 0.0, 1.0 );
494 _azimuthTable.addEntry( 10.0, 1.0 );
495 _azimuthTable.addEntry( 30.0, 0.75 );
496 _azimuthTable.addEntry( 40.0, 0.50 );
497 _azimuthTable.addEntry( 50.0, 0.20 );
498 _azimuthTable.addEntry( 60.0, 0.10 );
499 _azimuthTable.addEntry( 70.0, 0.20 );
500 _azimuthTable.addEntry( 80.0, 0.10 );
501 _azimuthTable.addEntry( 90.0, 0.05 );
502 _azimuthTable.addEntry( 105.0, 0.10 );
503 _azimuthTable.addEntry( 130.0, 0.05 );
504 _azimuthTable.addEntry( 150.0, 0.30 );
505 _azimuthTable.addEntry( 160.0, 0.40 );
506 _azimuthTable.addEntry( 170.0, 0.50 );
507 _azimuthTable.addEntry( 180.0, 0.50 );
509 _elevationTable.addEntry( 0.0, 0.1 );
510 _elevationTable.addEntry( 1.05, 1.0 );
511 _elevationTable.addEntry( 7.00, 1.0 );
512 _elevationTable.addEntry( 45.0, 0.3 );
513 _elevationTable.addEntry( 90.0, 0.1 );
514 _elevationTable.addEntry( 180.0, 0.01 );
517 double LOC::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
519 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
520 _elevationTable.interpolate( fabs(elevationAngle_deg) );
523 LOC::LOC( SGPropertyNode_ptr rootNode) :
524 NavRadioComponentWithIdent("loc", rootNode, new LOCAudioIdent(getIdentString(string("loc"), rootNode->getIndex()))),
526 _localizerOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
527 _localizerWidth_deg( rootNode->getNode(_name,true)->getNode("width-deg",true) )
535 FGNavList * LOC::getNavaidList()
537 return globals->get_loclist();
540 void LOC::search( double frequency, const SGGeod & aircraftPosition )
542 NavRadioComponentWithIdent::search( frequency, aircraftPosition );
543 if( false == valid() ) {
544 _localizerWidth_deg = 0.0;
548 // cache slightly expensive value,
549 // sanitized in FGNavRecord::localizerWidth() to never become zero
550 _localizerWidth_deg = _navRecord->localizerWidth();
553 /* Localizer coverage (ICAO Annex 10 Volume I 3.1.3.3
554 25NM within +/-10 deg from the front course line
555 17NM between 10 and 35deg from the front course line
556 10NM outside of +/- 35deg if coverage is provided
557 at and above a height of 2000ft above threshold or
558 1000ft above the highest point within intermediate
559 and final approach areas. Upper limit is a surface
560 extending outward from the localizer and inclined at
561 7 degrees above the horizontal
563 double LOC::getRange_nm(const SGGeod & aircraftPosition)
565 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
566 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
568 // looks like our navrecord declared range is based on 10NM?
569 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
572 double LOC::computeSignalQuality_norm( const SGGeod & aircraftPosition )
574 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
577 void LOC::update( double dt, const SGGeod & aircraftPosition )
579 NavRadioComponentWithIdent::update( dt, aircraftPosition );
581 if( false == valid() ) {
582 _localizerOffset_norm = 0.0;
586 double offset = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
588 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
589 // zeros i.e. six courses: one front course, one back course, and four
590 // false courses. Three of the six are reverse sensing.
591 offset = 30.0 * sawtooth(offset / 30.0);
593 // normalize offset to the localizer width, scale and clip to [-1..1]
594 offset = SGMiscd::clip( 2.0 * offset / _localizerWidth_deg, -1.0, 1.0 );
596 _localizerOffset_norm = offset;
599 void LOC::display( NavIndicator & navIndicator )
601 if( false == valid() )
604 navIndicator.showTo( true );
605 navIndicator.showFrom( false );
607 navIndicator.setCDI( _localizerOffset_norm * _signalQuality_norm );
608 navIndicator.setSignalQuality( _signalQuality_norm );
611 class GS : public NavRadioComponent {
613 GS( SGPropertyNode_ptr rootNode);
615 virtual void update( double dt, const SGGeod & aircraftPosition );
616 virtual void search( double frequency, const SGGeod & aircraftPosition );
617 virtual void display( NavIndicator & navIndicator );
619 virtual double getRange_nm(const SGGeod & aircraftPosition);
621 virtual FGNavList * getNavaidList();
624 class ServiceVolume {
627 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
629 SGInterpTable _azimuthTable;
630 SGInterpTable _elevationTable;
632 static SGVec3d tangentVector(const SGGeod& midpoint, const double heading);
634 PropertyObject<double> _targetGlideslope_deg;
635 PropertyObject<double> _glideslopeOffset_norm;
640 GS::ServiceVolume::ServiceVolume()
642 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
643 // ICAO Annex 10 - 3.1.5.2.2: The emission from the glide path equipment
644 // shall be horizontally polarized
645 // very rough abstraction of a 5-element yagi antenna's
646 // E-plane radiation diagram
647 _azimuthTable.addEntry( 0.0, 1.0 );
648 _azimuthTable.addEntry( 10.0, 1.0 );
649 _azimuthTable.addEntry( 30.0, 0.75 );
650 _azimuthTable.addEntry( 40.0, 0.50 );
651 _azimuthTable.addEntry( 50.0, 0.20 );
652 _azimuthTable.addEntry( 60.0, 0.10 );
653 _azimuthTable.addEntry( 70.0, 0.20 );
654 _azimuthTable.addEntry( 80.0, 0.10 );
655 _azimuthTable.addEntry( 90.0, 0.05 );
656 _azimuthTable.addEntry( 105.0, 0.10 );
657 _azimuthTable.addEntry( 130.0, 0.05 );
658 _azimuthTable.addEntry( 150.0, 0.30 );
659 _azimuthTable.addEntry( 160.0, 0.40 );
660 _azimuthTable.addEntry( 170.0, 0.50 );
661 _azimuthTable.addEntry( 180.0, 0.50 );
663 _elevationTable.addEntry( 0.0, 0.1 );
664 _elevationTable.addEntry( 1.05, 1.0 );
665 _elevationTable.addEntry( 7.00, 1.0 );
666 _elevationTable.addEntry( 45.0, 0.3 );
667 _elevationTable.addEntry( 90.0, 0.1 );
668 _elevationTable.addEntry( 180.0, 0.01 );
671 double GS::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
673 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
674 _elevationTable.interpolate( fabs(elevationAngle_deg) );
677 GS::GS( SGPropertyNode_ptr rootNode) :
678 NavRadioComponent("gs", rootNode ),
679 _targetGlideslope_deg( rootNode->getNode(_name,true)->getNode("slope",true) ),
680 _glideslopeOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
681 _gsAxis(SGVec3d::zeros()),
682 _gsVertical(SGVec3d::zeros())
690 FGNavList * GS::getNavaidList()
692 return globals->get_gslist();
695 double GS::getRange_nm(const SGGeod & aircraftPosition)
697 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
698 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - fmod(_navRecord->get_multiuse(), 1000.0) );
699 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
702 // Calculate a Cartesian unit vector in the
703 // local horizontal plane, i.e. tangent to the
704 // surface of the earth at the local ground zero.
705 // The tangent vector passes through the given <midpoint>
706 // and points forward along the given <heading>.
707 // The <heading> is given in degrees.
708 SGVec3d GS::tangentVector(const SGGeod& midpoint, const double heading)
710 // move 100m away from the midpoint - arbitrary number
711 const double delta(100.0);
713 double az2; // ignored
714 SGGeodesy::direct(midpoint, heading, delta, head, az2);
715 SGGeodesy::direct(midpoint, 180+heading, delta, tail, az2);
716 head.setElevationM(midpoint.getElevationM());
717 tail.setElevationM(midpoint.getElevationM());
718 SGVec3d head_xyz = SGVec3d::fromGeod(head);
719 SGVec3d tail_xyz = SGVec3d::fromGeod(tail);
720 // Awkward formula here, needed because vector-by-scalar
721 // multiplication is defined, but not vector-by-scalar division.
722 return (head_xyz - tail_xyz) * (0.5/delta);
725 void GS::search( double frequency, const SGGeod & aircraftPosition )
727 NavRadioComponent::search( frequency, aircraftPosition );
728 if( false == valid() ) {
729 _gsAxis = SGVec3d::zeros();
730 _gsVertical = SGVec3d::zeros();
731 _targetGlideslope_deg = 3.0;
735 double gs_radial = SGMiscd::normalizePeriodic(0.0, 360.0, fmod(_navRecord->get_multiuse(), 1000.0) );
737 _gsAxis = tangentVector(_navRecord->geod(), gs_radial);
738 SGVec3d gsBaseline = tangentVector(_navRecord->geod(), gs_radial + 90.0);
739 _gsVertical = cross(gsBaseline, _gsAxis);
741 int tmp = (int)(_navRecord->get_multiuse() / 1000.0);
742 // catch unconfigured glideslopes here, they will cause nan later
743 _targetGlideslope_deg = SGMiscd::max( 1.0, (double)tmp / 100.0 );
746 void GS::update( double dt, const SGGeod & aircraftPosition )
748 NavRadioComponent::update( dt, aircraftPosition );
749 if( false == valid() ) {
750 _glideslopeOffset_norm = 0.0;
754 SGVec3d pos = SGVec3d::fromGeod(aircraftPosition) - _navRecord->cart(); // relative vector from gs antenna to aircraft
755 // The positive GS axis points along the runway in the landing direction,
756 // toward the far end, not toward the approach area, so we need a - sign here:
757 double comp_h = -dot(pos, _gsAxis); // component in horiz direction
758 double comp_v = dot(pos, _gsVertical); // component in vertical direction
759 //double comp_b = dot(pos, _gsBaseline); // component in baseline direction
760 //if (comp_b) {} // ... (useful for debugging)
762 // _gsDirect represents the angle of elevation of the aircraft
763 // as seen by the GS transmitter.
764 double gsDirect = atan2(comp_v, comp_h) * SGD_RADIANS_TO_DEGREES;
765 // At this point, if the aircraft is centered on the glide slope,
766 // _gsDirect will be a small positive number, e.g. 3.0 degrees
768 // Aim the branch cut straight down
769 // into the ground below the GS transmitter:
770 if (gsDirect < -90.0) gsDirect += 360.0;
772 double offset = _targetGlideslope_deg - gsDirect;
774 offset = _targetGlideslope_deg/2 * sawtooth(2.0*offset/_targetGlideslope_deg);
775 assert( false == isnan(offset) );
776 // GS is documented to be 1.4 degrees thick,
777 // i.e. plus or minus 0.7 degrees from the midline:
778 _glideslopeOffset_norm = SGMiscd::clip(offset/0.7, -1.0, 1.0);
781 void GS::display( NavIndicator & navIndicator )
783 if( false == valid() ) {
784 navIndicator.setGS( false );
787 navIndicator.setGS( true );
788 navIndicator.setGS( _glideslopeOffset_norm );
791 /* ------------- A NAV/COMM Frequency formatter ---------------------- */
793 class FrequencyFormatter : public SGPropertyChangeListener {
795 FrequencyFormatter( SGPropertyNode_ptr freqNode, SGPropertyNode_ptr fmtFreqNode, double channelSpacing ) :
796 _freqNode( freqNode ),
797 _fmtFreqNode( fmtFreqNode ),
798 _channelSpacing(channelSpacing)
800 _freqNode->addChangeListener( this );
801 valueChanged(_freqNode);
803 ~FrequencyFormatter()
805 _freqNode->removeChangeListener( this );
808 void valueChanged (SGPropertyNode * prop)
810 // format as fixed decimal "nnn.nn"
811 std::ostringstream buf;
815 << std::setprecision(2)
817 _fmtFreqNode->setStringValue( buf.str() );
820 double getFrequency() const
822 double d = SGMiscd::roundToInt(_freqNode->getDoubleValue() / _channelSpacing) * _channelSpacing;
823 // strip last digit, do not round
824 return ((int)(d*100))/100.0;
828 SGPropertyNode_ptr _freqNode;
829 SGPropertyNode_ptr _fmtFreqNode;
830 double _channelSpacing;
834 /* ------------- The NavRadio implementation ---------------------- */
836 class NavRadioImpl : public NavRadio {
838 NavRadioImpl( SGPropertyNode_ptr node );
839 virtual ~NavRadioImpl();
841 virtual void update( double dt );
848 Legacy( NavRadioImpl * navRadioImpl ) : _navRadioImpl( navRadioImpl ) {}
851 void update( double dt );
853 NavRadioImpl * _navRadioImpl;
854 SGPropertyNode_ptr is_valid_node;
855 SGPropertyNode_ptr nav_serviceable_node;
856 SGPropertyNode_ptr nav_id_node;
857 SGPropertyNode_ptr id_c1_node;
858 SGPropertyNode_ptr id_c2_node;
859 SGPropertyNode_ptr id_c3_node;
860 SGPropertyNode_ptr id_c4_node;
863 const static int VOR_COMPONENT = 0;
864 const static int LOC_COMPONENT = 1;
865 const static int GS_COMPONENT = 2;
869 SGPropertyNode_ptr _rootNode;
870 FrequencyFormatter _useFrequencyFormatter;
871 FrequencyFormatter _stbyFrequencyFormatter;
872 std::vector<NavRadioComponent*> _components;
873 NavIndicator _navIndicator;
876 PropertyObject<bool> _cdiDisconnected;
879 NavRadioImpl::NavRadioImpl( SGPropertyNode_ptr node ) :
881 _name(node->getStringValue("name", "nav")),
882 _num(node->getIntValue("number", 0)),
883 _rootNode(fgGetNode( string("/instrumentation/") + _name, _num, true)),
884 _useFrequencyFormatter( _rootNode->getNode("frequencies/selected-mhz",true), _rootNode->getNode("frequencies/selected-mhz-fmt",true), 0.05 ),
885 _stbyFrequencyFormatter( _rootNode->getNode("frequencies/standby-mhz",true), _rootNode->getNode("frequencies/standby-mhz-fmt",true), 0.05 ),
886 _navIndicator(_rootNode),
889 _cdiDisconnected(_rootNode->getNode("cdi-disconnected",true))
893 NavRadioImpl::~NavRadioImpl()
895 BOOST_FOREACH( NavRadioComponent * p, _components ) {
900 void NavRadioImpl::init()
902 if( 0 < _components.size() )
905 _components.push_back( new VOR(_rootNode) );
906 _components.push_back( new LOC(_rootNode) );
907 _components.push_back( new GS(_rootNode) );
912 void NavRadioImpl::search()
916 void NavRadioImpl::update( double dt )
918 if( dt < SGLimitsd::min() ) return;
923 position = globals->get_aircraft_position();
925 catch( std::exception & ) {
930 if( _frequency != _useFrequencyFormatter.getFrequency() ) {
931 _frequency = _useFrequencyFormatter.getFrequency();
935 BOOST_FOREACH( NavRadioComponent * p, _components ) {
936 if( _stationTTL <= 0.0 )
937 p->search( _frequency, position );
938 p->update( dt, position );
940 if( false == _cdiDisconnected )
941 p->display( _navIndicator );
944 if( _stationTTL <= 0.0 )
947 _legacy.update( dt );
950 void NavRadioImpl::Legacy::init()
952 is_valid_node = _navRadioImpl->_rootNode->getChild("data-is-valid", 0, true);
953 nav_serviceable_node = _navRadioImpl->_rootNode->getChild("serviceable", 0, true);
955 nav_id_node = _navRadioImpl->_rootNode->getChild("nav-id", 0, true );
956 id_c1_node = _navRadioImpl->_rootNode->getChild("nav-id_asc1", 0, true );
957 id_c2_node = _navRadioImpl->_rootNode->getChild("nav-id_asc2", 0, true );
958 id_c3_node = _navRadioImpl->_rootNode->getChild("nav-id_asc3", 0, true );
959 id_c4_node = _navRadioImpl->_rootNode->getChild("nav-id_asc4", 0, true );
963 void NavRadioImpl::Legacy::update( double dt )
965 is_valid_node->setBoolValue(
966 _navRadioImpl->_components[VOR_COMPONENT]->valid() || _navRadioImpl->_components[LOC_COMPONENT]->valid()
969 string ident = _navRadioImpl->_components[VOR_COMPONENT]->getIdent();
971 ident = _navRadioImpl->_components[LOC_COMPONENT]->getIdent();
973 nav_id_node->setStringValue( ident );
975 ident = simgear::strutils::rpad( ident, 4, ' ' );
976 id_c1_node->setIntValue( (int)ident[0] );
977 id_c2_node->setIntValue( (int)ident[1] );
978 id_c3_node->setIntValue( (int)ident[2] );
979 id_c4_node->setIntValue( (int)ident[3] );
983 SGSubsystem * NavRadio::createInstance( SGPropertyNode_ptr rootNode )
985 // use old navradio code by default
986 if( fgGetBool( "/instrumentation/use-new-navradio", false ) )
987 return new NavRadioImpl( rootNode );
989 return new FGNavRadio( rootNode );
992 } // namespace Instrumentation