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/interpolater.hxx>
33 #include <simgear/sg_inlines.h>
34 #include <simgear/props/propertyObject.hxx>
35 #include <simgear/misc/strutils.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; }
147 virtual const std::string getIdent() const { return _ident; }
150 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
151 virtual FGNavList * getNavaidList() = 0;
153 // General-purpose sawtooth function. Graph looks like this:
156 // Odd symmetry, inversion symmetry about the origin.
157 // Unit slope at the origin.
158 // Max 1, min -1, period 4.
159 // Two zero-crossings per period, one with + slope, one with - slope.
160 // Useful for false localizer courses.
161 static double sawtooth(double xx)
163 return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
166 SGPropertyNode_ptr _rootNode;
167 const std::string _name;
168 FGNavRecord * _navRecord;
169 PropertyObject<bool> _serviceable;
170 PropertyObject<double> _signalQuality_norm;
171 PropertyObject<double> _trueBearingTo_deg;
172 PropertyObject<double> _trueBearingFrom_deg;
173 PropertyObject<double> _trackDistance_m;
174 PropertyObject<double> _slantDistance_m;
175 PropertyObject<double> _heightAboveStation_ft;
176 PropertyObject<string> _ident;
177 PropertyObject<bool> _inRange;
178 PropertyObject<double> _range_nm;
181 class NavRadioComponentWithIdent : public NavRadioComponent {
183 NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent );
184 virtual ~NavRadioComponentWithIdent();
185 void update( double dt, const SGGeod & aircraftPosition );
187 static std::string getIdentString( const std::string & name, int index );
189 AudioIdent * _audioIdent;
190 PropertyObject<double> _identVolume;
191 PropertyObject<bool> _identEnabled;
194 std::string NavRadioComponentWithIdent::getIdentString( const std::string & name, int index )
196 std::ostringstream temp;
197 temp << name << "-ident-" << index;
201 NavRadioComponentWithIdent::NavRadioComponentWithIdent( const std::string & name, SGPropertyNode_ptr rootNode, AudioIdent * audioIdent ) :
202 NavRadioComponent( name, rootNode ),
203 _audioIdent( audioIdent ),
204 _identVolume( rootNode->getNode(name,true)->getNode("ident-volume",true) ),
205 _identEnabled( rootNode->getNode(name,true)->getNode("ident-enabled",true) )
210 NavRadioComponentWithIdent::~NavRadioComponentWithIdent()
215 void NavRadioComponentWithIdent::update( double dt, const SGGeod & aircraftPosition )
217 NavRadioComponent::update( dt, aircraftPosition );
218 _audioIdent->update( dt );
220 if( false == ( valid() && _identEnabled && _signalQuality_norm > 0.1 ) ) {
221 _audioIdent->setIdent("", 0.0 );
224 _audioIdent->setIdent( _ident, SGMiscd::clip(_identVolume, 0.0, 1.0) );
227 NavRadioComponent::NavRadioComponent( const std::string & name, SGPropertyNode_ptr rootNode ) :
231 _serviceable( rootNode->getNode(name,true)->getNode("serviceable",true) ),
232 _signalQuality_norm( rootNode->getNode(name,true)->getNode("signal-quality-norm",true) ),
233 _trueBearingTo_deg( rootNode->getNode(name,true)->getNode("true-bearing-to-deg",true) ),
234 _trueBearingFrom_deg( rootNode->getNode(name,true)->getNode("true-bearing-from-deg",true) ),
235 _trackDistance_m( rootNode->getNode(name,true)->getNode("track-distance-m",true) ),
236 _slantDistance_m( rootNode->getNode(name,true)->getNode("slant-distance-m",true) ),
237 _heightAboveStation_ft( rootNode->getNode(name,true)->getNode("height-above-station-ft",true) ),
238 _ident( rootNode->getNode(name,true)->getNode("ident",true) ),
239 _inRange( rootNode->getNode(name,true)->getNode("in-range",true) ),
240 _range_nm( rootNode->getNode(_name,true)->getNode("range-nm",true) )
242 simgear::props::Type typ = _serviceable.node()->getType();
243 if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED))
247 NavRadioComponent::~NavRadioComponent()
251 double NavRadioComponent::getRange_nm( const SGGeod & aircraftPosition )
253 if( _navRecord == NULL ) return 0.0; // no station: no range
254 double d = _navRecord->get_range();
255 if( d <= SGLimitsd::min() ) return 25.0; // no configured range: arbitrary number
256 return d; // configured range
259 void NavRadioComponent::search( double frequency, const SGGeod & aircraftPosition )
261 if( NULL == (_navRecord = getNavaidList()->findByFreq(frequency, aircraftPosition )) ) {
262 SG_LOG(SG_INSTR,SG_ALERT, "No " << _name << " available at " << frequency );
266 SG_LOG(SG_INSTR,SG_ALERT, "Using " << _name << "'" << _navRecord->get_ident() << "' for " << frequency );
267 _ident = _navRecord->ident();
270 double NavRadioComponent::computeSignalQuality_norm( const SGGeod & aircraftPosition )
272 if( false == valid() ) return 0.0;
274 double distance_nm = _slantDistance_m * SG_METER_TO_NM;
275 double range_nm = _range_nm;
277 // assume signal quality is 100% up to the published range and
278 // decay with the distance squared further out
279 if ( distance_nm <= range_nm ) return 1.0;
280 return range_nm*range_nm/(distance_nm*distance_nm);
283 void NavRadioComponent::update( double dt, const SGGeod & aircraftPosition )
285 if( false == valid() ) {
286 _signalQuality_norm = 0.0;
287 _trueBearingTo_deg = 0.0;
288 _trueBearingFrom_deg = 0.0;
289 _trackDistance_m = 0.0;
290 _slantDistance_m = 0.0;
294 _slantDistance_m = dist(_navRecord->cart(), SGVec3d::fromGeod(aircraftPosition));
296 double az1 = 0.0, az2 = 0.0, dist = 0.0;
297 SGGeodesy::inverse(aircraftPosition, _navRecord->geod(), az1, az2, dist );
298 _trueBearingTo_deg = az1; _trueBearingFrom_deg = az2; _trackDistance_m = dist;
299 _heightAboveStation_ft = SGMiscd::max(0.0, aircraftPosition.getElevationFt() - _navRecord->get_elev_ft());
301 _range_nm = getRange_nm(aircraftPosition);
302 _signalQuality_norm = computeSignalQuality_norm( aircraftPosition );
303 _inRange = _signalQuality_norm > 0.2;
306 /* ---------------------------------------------------------------- */
308 static std::string VORTablePath( const char * name )
310 SGPath path( globals->get_fg_root() );
311 path.append( "Navaids" );
316 class VOR : public NavRadioComponentWithIdent {
318 VOR( SGPropertyNode_ptr rootNode);
320 virtual void update( double dt, const SGGeod & aircraftPosition );
321 virtual void display( NavIndicator & navIndicator );
322 virtual double getRange_nm(const SGGeod & aircraftPosition);
324 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
325 virtual FGNavList * getNavaidList();
329 class ServiceVolume {
332 term_tbl(VORTablePath("range.term")),
333 low_tbl(VORTablePath("range.low")),
334 high_tbl(VORTablePath("range.high")) {
336 double adjustRange( double height_ft, double nominalRange_nm );
339 SGInterpTable term_tbl;
340 SGInterpTable low_tbl;
341 SGInterpTable high_tbl;
344 PropertyObject<double> _radial;
345 PropertyObject<double> _radialInbound;
348 // model standard VOR/DME/TACAN service volumes as per AIM 1-1-8
349 double VOR::ServiceVolume::adjustRange( double height_ft, double nominalRange_nm )
351 if (nominalRange_nm < SGLimitsd::min() )
352 nominalRange_nm = FG_NAV_DEFAULT_RANGE;
354 // extend out actual usable range to be 1.3x the published safe range
355 const double usability_factor = 1.3;
357 // assumptions we model the standard service volume, plus
358 // ... rather than specifying a cylinder, we model a cone that
359 // contains the cylinder. Then we put an upside down cone on top
360 // to model diminishing returns at too-high altitudes.
362 if ( nominalRange_nm < 25.0 + SG_EPSILON ) {
363 // Standard Terminal Service Volume
364 return term_tbl.interpolate( height_ft ) * usability_factor;
365 } else if ( nominalRange_nm < 50.0 + SG_EPSILON ) {
366 // Standard Low Altitude Service Volume
367 // table is based on range of 40, scale to actual range
368 return low_tbl.interpolate( height_ft ) * nominalRange_nm / 40.0
371 // Standard High Altitude Service Volume
372 // table is based on range of 130, scale to actual range
373 return high_tbl.interpolate( height_ft ) * nominalRange_nm / 130.0
378 VOR::VOR( SGPropertyNode_ptr rootNode) :
379 NavRadioComponentWithIdent("vor", rootNode, new VORAudioIdent(getIdentString(string("vor"), rootNode->getIndex()))),
381 _radial( rootNode->getNode(_name,true)->getNode("radial",true) ),
382 _radialInbound( rootNode->getNode(_name,true)->getNode("radial-inbound",true) )
390 double VOR::getRange_nm( const SGGeod & aircraftPosition )
392 return _serviceVolume.adjustRange( _heightAboveStation_ft, _navRecord->get_range() );
395 FGNavList * VOR::getNavaidList()
397 return globals->get_navlist();
400 double VOR::computeSignalQuality_norm( const SGGeod & aircraftPosition )
402 // apply cone of confusion. Some sources say it's opening angle is 53deg, others estimate
403 // a diameter of 1NM per 6000ft (approx. 45deg). ICAO Annex 10 says minimum 40deg.
404 // We use 1NM@6000ft and a distance-squared
405 // function to make signal-quality=100% 0.5NM@6000ft from the center and zero overhead
406 double cone_of_confusion_width = 0.5 * _heightAboveStation_ft / 6000.0 * SG_NM_TO_METER;
407 if( _trackDistance_m < cone_of_confusion_width ) {
408 double d = cone_of_confusion_width <= SGLimitsd::min() ? 1 :
409 (1 - _trackDistance_m/cone_of_confusion_width);
413 // use default decay function outside the cone of confusion
414 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
417 void VOR::update( double dt, const SGGeod & aircraftPosition )
420 NavRadioComponentWithIdent::update( dt, aircraftPosition );
422 if( false == valid() ) {
427 // an arbitrary error function
428 double error = 0.5*(sin(_totalTime/11.0) + sin(_totalTime/23.0));
430 // add 1% error at 100% signal-quality
431 // add 50% error at 0% signal-quality
432 // of full deflection (+/-10deg)
433 double e = 10.0 * ( 0.01 + (1-_signalQuality_norm) * 0.49 ) * error;
435 // compute magnetic bearing from the station (aka current radial)
436 double r = SGMiscd::normalizePeriodic(0.0, 360.0, _trueBearingFrom_deg - _navRecord->get_multiuse() + e );
439 _radialInbound = SGMiscd::normalizePeriodic(0.0,360.0, 180.0 + _radial);
442 void VOR::display( NavIndicator & navIndicator )
444 if( false == valid() ) return;
446 double offset = SGMiscd::normalizePeriodic(-180.0,180.0,_radial - navIndicator.getSelectedCourse());
447 bool to = fabs(offset) >= 90.0;
449 if( to ) offset = -offset + copysign(180.0,offset);
451 navIndicator.showTo( to );
452 navIndicator.showFrom( !to );
453 // normalize to +/- 1.0 for +/- 10deg, decrease deflection with decreasing signal
454 navIndicator.setCDI( SGMiscd::clip( -offset/10.0, -1.0, 1.0 ) * _signalQuality_norm );
455 navIndicator.setSignalQuality( _signalQuality_norm );
458 /* ---------------------------------------------------------------- */
459 class LOC : public NavRadioComponentWithIdent {
461 LOC( SGPropertyNode_ptr rootNode );
463 virtual void update( double dt, const SGGeod & aircraftPosition );
464 virtual void search( double frequency, const SGGeod & aircraftPosition );
465 virtual void display( NavIndicator & navIndicator );
466 virtual double getRange_nm(const SGGeod & aircraftPosition);
469 virtual double computeSignalQuality_norm( const SGGeod & aircraftPosition );
470 virtual FGNavList * getNavaidList();
473 class ServiceVolume {
476 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
478 SGInterpTable _azimuthTable;
479 SGInterpTable _elevationTable;
481 PropertyObject<double> _localizerOffset_norm;
482 PropertyObject<double> _localizerWidth_deg;
485 LOC::ServiceVolume::ServiceVolume()
487 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
488 // ICAO Annex 10 - 3.1.3.2.2: The emission from the localizer
489 // shall be horizontally polarized
490 // very rough abstraction of a 5-element yagi antenna's
491 // E-plane radiation diagram
492 _azimuthTable.addEntry( 0.0, 1.0 );
493 _azimuthTable.addEntry( 10.0, 1.0 );
494 _azimuthTable.addEntry( 30.0, 0.75 );
495 _azimuthTable.addEntry( 40.0, 0.50 );
496 _azimuthTable.addEntry( 50.0, 0.20 );
497 _azimuthTable.addEntry( 60.0, 0.10 );
498 _azimuthTable.addEntry( 70.0, 0.20 );
499 _azimuthTable.addEntry( 80.0, 0.10 );
500 _azimuthTable.addEntry( 90.0, 0.05 );
501 _azimuthTable.addEntry( 105.0, 0.10 );
502 _azimuthTable.addEntry( 130.0, 0.05 );
503 _azimuthTable.addEntry( 150.0, 0.30 );
504 _azimuthTable.addEntry( 160.0, 0.40 );
505 _azimuthTable.addEntry( 170.0, 0.50 );
506 _azimuthTable.addEntry( 180.0, 0.50 );
508 _elevationTable.addEntry( 0.0, 0.1 );
509 _elevationTable.addEntry( 1.05, 1.0 );
510 _elevationTable.addEntry( 7.00, 1.0 );
511 _elevationTable.addEntry( 45.0, 0.3 );
512 _elevationTable.addEntry( 90.0, 0.1 );
513 _elevationTable.addEntry( 180.0, 0.01 );
516 double LOC::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
518 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
519 _elevationTable.interpolate( fabs(elevationAngle_deg) );
522 LOC::LOC( SGPropertyNode_ptr rootNode) :
523 NavRadioComponentWithIdent("loc", rootNode, new LOCAudioIdent(getIdentString(string("loc"), rootNode->getIndex()))),
525 _localizerOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
526 _localizerWidth_deg( rootNode->getNode(_name,true)->getNode("width-deg",true) )
534 FGNavList * LOC::getNavaidList()
536 return globals->get_loclist();
539 void LOC::search( double frequency, const SGGeod & aircraftPosition )
541 NavRadioComponentWithIdent::search( frequency, aircraftPosition );
542 if( false == valid() ) {
543 _localizerWidth_deg = 0.0;
547 // cache slightly expensive value,
548 // sanitized in FGNavRecord::localizerWidth() to never become zero
549 _localizerWidth_deg = _navRecord->localizerWidth();
552 /* Localizer coverage (ICAO Annex 10 Volume I 3.1.3.3
553 25NM within +/-10 deg from the front course line
554 17NM between 10 and 35deg from the front course line
555 10NM outside of +/- 35deg if coverage is provided
556 at and above a height of 2000ft above threshold or
557 1000ft above the highest point within intermediate
558 and final approach areas. Upper limit is a surface
559 extending outward from the localizer and inclined at
560 7 degrees above the horizontal
562 double LOC::getRange_nm(const SGGeod & aircraftPosition)
564 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
565 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
567 // looks like our navrecord declared range is based on 10NM?
568 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
571 double LOC::computeSignalQuality_norm( const SGGeod & aircraftPosition )
573 return NavRadioComponentWithIdent::computeSignalQuality_norm( aircraftPosition );
576 void LOC::update( double dt, const SGGeod & aircraftPosition )
578 NavRadioComponentWithIdent::update( dt, aircraftPosition );
580 if( false == valid() ) {
581 _localizerOffset_norm = 0.0;
585 double offset = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - _navRecord->get_multiuse() );
587 // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
588 // zeros i.e. six courses: one front course, one back course, and four
589 // false courses. Three of the six are reverse sensing.
590 offset = 30.0 * sawtooth(offset / 30.0);
592 // normalize offset to the localizer width, scale and clip to [-1..1]
593 offset = SGMiscd::clip( 2.0 * offset / _localizerWidth_deg, -1.0, 1.0 );
595 _localizerOffset_norm = offset;
598 void LOC::display( NavIndicator & navIndicator )
600 if( false == valid() )
603 navIndicator.showTo( true );
604 navIndicator.showFrom( false );
606 navIndicator.setCDI( _localizerOffset_norm * _signalQuality_norm );
607 navIndicator.setSignalQuality( _signalQuality_norm );
610 class GS : public NavRadioComponent {
612 GS( SGPropertyNode_ptr rootNode);
614 virtual void update( double dt, const SGGeod & aircraftPosition );
615 virtual void search( double frequency, const SGGeod & aircraftPosition );
616 virtual void display( NavIndicator & navIndicator );
618 virtual double getRange_nm(const SGGeod & aircraftPosition);
620 virtual FGNavList * getNavaidList();
623 class ServiceVolume {
626 double adjustRange( double azimuthAngle_deg, double elevationAngle_deg );
628 SGInterpTable _azimuthTable;
629 SGInterpTable _elevationTable;
631 static SGVec3d tangentVector(const SGGeod& midpoint, const double heading);
633 PropertyObject<double> _targetGlideslope_deg;
634 PropertyObject<double> _glideslopeOffset_norm;
639 GS::ServiceVolume::ServiceVolume()
641 // maybe this: http://www.tpub.com/content/aviation2/P-1244/P-12440125.htm
642 // ICAO Annex 10 - 3.1.5.2.2: The emission from the glide path equipment
643 // shall be horizontally polarized
644 // very rough abstraction of a 5-element yagi antenna's
645 // E-plane radiation diagram
646 _azimuthTable.addEntry( 0.0, 1.0 );
647 _azimuthTable.addEntry( 10.0, 1.0 );
648 _azimuthTable.addEntry( 30.0, 0.75 );
649 _azimuthTable.addEntry( 40.0, 0.50 );
650 _azimuthTable.addEntry( 50.0, 0.20 );
651 _azimuthTable.addEntry( 60.0, 0.10 );
652 _azimuthTable.addEntry( 70.0, 0.20 );
653 _azimuthTable.addEntry( 80.0, 0.10 );
654 _azimuthTable.addEntry( 90.0, 0.05 );
655 _azimuthTable.addEntry( 105.0, 0.10 );
656 _azimuthTable.addEntry( 130.0, 0.05 );
657 _azimuthTable.addEntry( 150.0, 0.30 );
658 _azimuthTable.addEntry( 160.0, 0.40 );
659 _azimuthTable.addEntry( 170.0, 0.50 );
660 _azimuthTable.addEntry( 180.0, 0.50 );
662 _elevationTable.addEntry( 0.0, 0.1 );
663 _elevationTable.addEntry( 1.05, 1.0 );
664 _elevationTable.addEntry( 7.00, 1.0 );
665 _elevationTable.addEntry( 45.0, 0.3 );
666 _elevationTable.addEntry( 90.0, 0.1 );
667 _elevationTable.addEntry( 180.0, 0.01 );
670 double GS::ServiceVolume::adjustRange( double azimuthAngle_deg, double elevationAngle_deg )
672 return _azimuthTable.interpolate( fabs(azimuthAngle_deg) ) *
673 _elevationTable.interpolate( fabs(elevationAngle_deg) );
676 GS::GS( SGPropertyNode_ptr rootNode) :
677 NavRadioComponent("gs", rootNode ),
678 _targetGlideslope_deg( rootNode->getNode(_name,true)->getNode("slope",true) ),
679 _glideslopeOffset_norm( rootNode->getNode(_name,true)->getNode("offset-norm",true) ),
680 _gsAxis(SGVec3d::zeros()),
681 _gsVertical(SGVec3d::zeros())
689 FGNavList * GS::getNavaidList()
691 return globals->get_gslist();
694 double GS::getRange_nm(const SGGeod & aircraftPosition)
696 double elevationAngle = ::atan2(_heightAboveStation_ft*SG_FEET_TO_METER, _trackDistance_m)*SG_RADIANS_TO_DEGREES;
697 double azimuthAngle = SGMiscd::normalizePeriodic( -180.0, 180.0, _trueBearingFrom_deg + 180.0 - fmod(_navRecord->get_multiuse(), 1000.0) );
698 return _navRecord->get_range() * _serviceVolume.adjustRange( azimuthAngle, elevationAngle );
701 // Calculate a Cartesian unit vector in the
702 // local horizontal plane, i.e. tangent to the
703 // surface of the earth at the local ground zero.
704 // The tangent vector passes through the given <midpoint>
705 // and points forward along the given <heading>.
706 // The <heading> is given in degrees.
707 SGVec3d GS::tangentVector(const SGGeod& midpoint, const double heading)
709 // move 100m away from the midpoint - arbitrary number
710 const double delta(100.0);
712 double az2; // ignored
713 SGGeodesy::direct(midpoint, heading, delta, head, az2);
714 SGGeodesy::direct(midpoint, 180+heading, delta, tail, az2);
715 head.setElevationM(midpoint.getElevationM());
716 tail.setElevationM(midpoint.getElevationM());
717 SGVec3d head_xyz = SGVec3d::fromGeod(head);
718 SGVec3d tail_xyz = SGVec3d::fromGeod(tail);
719 // Awkward formula here, needed because vector-by-scalar
720 // multiplication is defined, but not vector-by-scalar division.
721 return (head_xyz - tail_xyz) * (0.5/delta);
724 void GS::search( double frequency, const SGGeod & aircraftPosition )
726 NavRadioComponent::search( frequency, aircraftPosition );
727 if( false == valid() ) {
728 _gsAxis = SGVec3d::zeros();
729 _gsVertical = SGVec3d::zeros();
730 _targetGlideslope_deg = 3.0;
734 double gs_radial = SGMiscd::normalizePeriodic(0.0, 360.0, fmod(_navRecord->get_multiuse(), 1000.0) );
736 _gsAxis = tangentVector(_navRecord->geod(), gs_radial);
737 SGVec3d gsBaseline = tangentVector(_navRecord->geod(), gs_radial + 90.0);
738 _gsVertical = cross(gsBaseline, _gsAxis);
740 int tmp = (int)(_navRecord->get_multiuse() / 1000.0);
741 // catch unconfigured glideslopes here, they will cause nan later
742 _targetGlideslope_deg = SGMiscd::max( 1.0, (double)tmp / 100.0 );
745 void GS::update( double dt, const SGGeod & aircraftPosition )
747 NavRadioComponent::update( dt, aircraftPosition );
748 if( false == valid() ) {
749 _glideslopeOffset_norm = 0.0;
753 SGVec3d pos = SGVec3d::fromGeod(aircraftPosition) - _navRecord->cart(); // relative vector from gs antenna to aircraft
754 // The positive GS axis points along the runway in the landing direction,
755 // toward the far end, not toward the approach area, so we need a - sign here:
756 double comp_h = -dot(pos, _gsAxis); // component in horiz direction
757 double comp_v = dot(pos, _gsVertical); // component in vertical direction
758 //double comp_b = dot(pos, _gsBaseline); // component in baseline direction
759 //if (comp_b) {} // ... (useful for debugging)
761 // _gsDirect represents the angle of elevation of the aircraft
762 // as seen by the GS transmitter.
763 double gsDirect = atan2(comp_v, comp_h) * SGD_RADIANS_TO_DEGREES;
764 // At this point, if the aircraft is centered on the glide slope,
765 // _gsDirect will be a small positive number, e.g. 3.0 degrees
767 // Aim the branch cut straight down
768 // into the ground below the GS transmitter:
769 if (gsDirect < -90.0) gsDirect += 360.0;
771 double offset = _targetGlideslope_deg - gsDirect;
773 offset = _targetGlideslope_deg/2 * sawtooth(2.0*offset/_targetGlideslope_deg);
774 assert( false == isnan(offset) );
775 // GS is documented to be 1.4 degrees thick,
776 // i.e. plus or minus 0.7 degrees from the midline:
777 _glideslopeOffset_norm = SGMiscd::clip(offset/0.7, -1.0, 1.0);
780 void GS::display( NavIndicator & navIndicator )
782 if( false == valid() ) {
783 navIndicator.setGS( false );
786 navIndicator.setGS( true );
787 navIndicator.setGS( _glideslopeOffset_norm );
790 /* ------------- A NAV/COMM Frequency formatter ---------------------- */
792 class FrequencyFormatter : public SGPropertyChangeListener {
794 FrequencyFormatter( SGPropertyNode_ptr freqNode, SGPropertyNode_ptr fmtFreqNode, double channelSpacing ) :
795 _freqNode( freqNode ),
796 _fmtFreqNode( fmtFreqNode ),
797 _channelSpacing(channelSpacing)
799 _freqNode->addChangeListener( this );
800 valueChanged(_freqNode);
802 ~FrequencyFormatter()
804 _freqNode->removeChangeListener( this );
807 void valueChanged (SGPropertyNode * prop)
809 // format as fixed decimal "nnn.nn"
810 std::ostringstream buf;
814 << std::setprecision(2)
816 _fmtFreqNode->setStringValue( buf.str() );
819 double getFrequency() const
821 double d = SGMiscd::roundToInt(_freqNode->getDoubleValue() / _channelSpacing) * _channelSpacing;
822 // strip last digit, do not round
823 return ((int)(d*100))/100.0;
827 SGPropertyNode_ptr _freqNode;
828 SGPropertyNode_ptr _fmtFreqNode;
829 double _channelSpacing;
833 /* ------------- The NavRadio implementation ---------------------- */
835 class NavRadioImpl : public NavRadio {
837 NavRadioImpl( SGPropertyNode_ptr node );
838 virtual ~NavRadioImpl();
840 virtual void update( double dt );
847 Legacy( NavRadioImpl * navRadioImpl ) : _navRadioImpl( navRadioImpl ) {}
850 void update( double dt );
852 NavRadioImpl * _navRadioImpl;
853 SGPropertyNode_ptr is_valid_node;
854 SGPropertyNode_ptr nav_serviceable_node;
855 SGPropertyNode_ptr nav_id_node;
856 SGPropertyNode_ptr id_c1_node;
857 SGPropertyNode_ptr id_c2_node;
858 SGPropertyNode_ptr id_c3_node;
859 SGPropertyNode_ptr id_c4_node;
862 const static int VOR_COMPONENT = 0;
863 const static int LOC_COMPONENT = 1;
864 const static int GS_COMPONENT = 2;
868 SGPropertyNode_ptr _rootNode;
869 FrequencyFormatter _useFrequencyFormatter;
870 FrequencyFormatter _stbyFrequencyFormatter;
871 std::vector<NavRadioComponent*> _components;
872 NavIndicator _navIndicator;
875 PropertyObject<bool> _cdiDisconnected;
878 NavRadioImpl::NavRadioImpl( SGPropertyNode_ptr node ) :
880 _name(node->getStringValue("name", "nav")),
881 _num(node->getIntValue("number", 0)),
882 _rootNode(fgGetNode( string("/instrumentation/") + _name, _num, true)),
883 _useFrequencyFormatter( _rootNode->getNode("frequencies/selected-mhz",true), _rootNode->getNode("frequencies/selected-mhz-fmt",true), 0.05 ),
884 _stbyFrequencyFormatter( _rootNode->getNode("frequencies/standby-mhz",true), _rootNode->getNode("frequencies/standby-mhz-fmt",true), 0.05 ),
885 _navIndicator(_rootNode),
888 _cdiDisconnected(_rootNode->getNode("cdi-disconnected",true))
892 NavRadioImpl::~NavRadioImpl()
894 BOOST_FOREACH( NavRadioComponent * p, _components ) {
899 void NavRadioImpl::init()
901 if( 0 < _components.size() )
904 _components.push_back( new VOR(_rootNode) );
905 _components.push_back( new LOC(_rootNode) );
906 _components.push_back( new GS(_rootNode) );
911 void NavRadioImpl::search()
915 void NavRadioImpl::update( double dt )
917 if( dt < SGLimitsd::min() ) return;
922 position = globals->get_aircraft_position();
924 catch( std::exception & ) {
929 if( _frequency != _useFrequencyFormatter.getFrequency() ) {
930 _frequency = _useFrequencyFormatter.getFrequency();
934 BOOST_FOREACH( NavRadioComponent * p, _components ) {
935 if( _stationTTL <= 0.0 )
936 p->search( _frequency, position );
937 p->update( dt, position );
939 if( false == _cdiDisconnected )
940 p->display( _navIndicator );
943 if( _stationTTL <= 0.0 )
946 _legacy.update( dt );
949 void NavRadioImpl::Legacy::init()
951 is_valid_node = _navRadioImpl->_rootNode->getChild("data-is-valid", 0, true);
952 nav_serviceable_node = _navRadioImpl->_rootNode->getChild("serviceable", 0, true);
954 nav_id_node = _navRadioImpl->_rootNode->getChild("nav-id", 0, true );
955 id_c1_node = _navRadioImpl->_rootNode->getChild("nav-id_asc1", 0, true );
956 id_c2_node = _navRadioImpl->_rootNode->getChild("nav-id_asc2", 0, true );
957 id_c3_node = _navRadioImpl->_rootNode->getChild("nav-id_asc3", 0, true );
958 id_c4_node = _navRadioImpl->_rootNode->getChild("nav-id_asc4", 0, true );
962 void NavRadioImpl::Legacy::update( double dt )
964 is_valid_node->setBoolValue(
965 _navRadioImpl->_components[VOR_COMPONENT]->valid() || _navRadioImpl->_components[LOC_COMPONENT]->valid()
968 string ident = _navRadioImpl->_components[VOR_COMPONENT]->getIdent();
970 ident = _navRadioImpl->_components[LOC_COMPONENT]->getIdent();
972 nav_id_node->setStringValue( ident );
974 ident = simgear::strutils::rpad( ident, 4, ' ' );
975 id_c1_node->setIntValue( (int)ident[0] );
976 id_c2_node->setIntValue( (int)ident[1] );
977 id_c3_node->setIntValue( (int)ident[2] );
978 id_c4_node->setIntValue( (int)ident[3] );
982 SGSubsystem * NavRadio::createInstance( SGPropertyNode_ptr rootNode )
984 // use old navradio code by default
985 if( fgGetBool( "/instrumentation/use-new-navradio", false ) )
986 return new NavRadioImpl( rootNode );
988 return new FGNavRadio( rootNode );
991 } // namespace Instrumentation