# include <config.h>
#endif
+#include "navradio.hxx"
+
#include <sstream>
#include <simgear/sg_inlines.h>
#include <simgear/structure/exception.hxx>
#include <simgear/math/interpolater.hxx>
-#include "Navaids/navrecord.hxx"
+#include <Navaids/navrecord.hxx>
+
+#include <Airports/runways.hxx>
#include <Navaids/navlist.hxx>
#include <Main/util.hxx>
-#include "navradio.hxx"
+
using std::string;
+// General-purpose sawtooth function. Graph looks like this:
+// /\ .
+// \/
+// Odd symmetry, inversion symmetry about the origin.
+// Unit slope at the origin.
+// Max 1, min -1, period 4.
+// Two zero-crossings per period, one with + slope, one with - slope.
+// Useful for false localizer courses.
+static double sawtooth(double xx)
+{
+ return 4.0 * fabs(xx/4.0 + 0.25 - floor(xx/4.0 + 0.75)) - 1.0;
+}
+
+// Calculate a unit vector in the horizontal tangent plane
+// starting at the given "tail" of the vector and going off
+// with the given heading.
+static SGVec3d tangentVector(const SGGeod& tail, const SGVec3d& tail_xyz,
+ const double heading)
+{
+// The fudge factor here is presumably intended to improve
+// numerical stability. I don't know if it is necessary.
+// It gets divided out later.
+ double fudge(100.0);
+ SGGeod head;
+ double az2; // ignored
+ SGGeodesy::direct(tail, heading, fudge, head, az2);
+ head.setElevationM(tail.getElevationM());
+ SGVec3d head_xyz = SGVec3d::fromGeod(head);
+ return (head_xyz - tail_xyz) * (1.0/fudge);
+}
+
+// Create a "serviceable" node with a default value of "true"
+SGPropertyNode_ptr createServiceableProp(SGPropertyNode* aParent, const char* aName)
+{
+ SGPropertyNode_ptr n = (aParent->getChild(aName, 0, true)->getChild("serviceable", 0, true));
+ simgear::props::Type typ = n->getType();
+ if ((typ == simgear::props::NONE) || (typ == simgear::props::UNSPECIFIED)) {
+ n->setBoolValue(true);
+ }
+ return n;
+}
+
// Constructor
FGNavRadio::FGNavRadio(SGPropertyNode *node) :
lon_node(fgGetNode("/position/longitude-deg", true)),
cdi_serviceable_node(NULL),
gs_serviceable_node(NULL),
tofrom_serviceable_node(NULL),
+ dme_serviceable_node(NULL),
fmt_freq_node(NULL),
fmt_alt_freq_node(NULL),
heading_node(NULL),
gs_deflection_norm_node(NULL),
gs_rate_of_climb_node(NULL),
gs_dist_node(NULL),
+ gs_inrange_node(NULL),
nav_id_node(NULL),
id_c1_node(NULL),
id_c2_node(NULL),
last_x(0.0),
last_loc_dist(0.0),
last_xtrack_error(0.0),
+ _localizerWidth(5.0),
_name(node->getStringValue("name", "nav")),
_num(node->getIntValue("number", 0)),
- _time_before_search_sec(-1.0)
+ _time_before_search_sec(-1.0),
+ _falseCoursesEnabled(true),
+ _sgr(NULL)
{
SGPath path( globals->get_fg_root() );
SGPath term = path;
void
FGNavRadio::init ()
{
+ SGSoundMgr *smgr = (SGSoundMgr *)globals->get_subsystem("soundmgr");
+ _sgr = smgr->find("avionics", true);
+ _sgr->tie_to_listener();
+
morse.init();
string branch;
audio_btn_node->setBoolValue( true );
backcourse_node = node->getChild("back-course-btn", 0, true);
backcourse_node->setBoolValue( false );
+
nav_serviceable_node = node->getChild("serviceable", 0, true);
- cdi_serviceable_node = (node->getChild("cdi", 0, true))
- ->getChild("serviceable", 0, true);
- gs_serviceable_node = (node->getChild("gs", 0, true))
- ->getChild("serviceable");
- tofrom_serviceable_node = (node->getChild("to-from", 0, true))
- ->getChild("serviceable", 0, true);
-
+ cdi_serviceable_node = createServiceableProp(node, "cdi");
+ gs_serviceable_node = createServiceableProp(node, "gs");
+ tofrom_serviceable_node = createServiceableProp(node, "to-from");
+ dme_serviceable_node = createServiceableProp(node, "dme");
+
+ globals->get_props()->tie("sim/realism/false-radio-courses-enabled",
+ SGRawValuePointer<bool>(&_falseCoursesEnabled));
+
// frequencies
SGPropertyNode *subnode = node->getChild("frequencies", 0, true);
freq_node = subnode->getChild("selected-mhz", 0, true);
gs_deflection_norm_node = node->getChild("gs-needle-deflection-norm", 0, true);
gs_rate_of_climb_node = node->getChild("gs-rate-of-climb", 0, true);
gs_dist_node = node->getChild("gs-distance", 0, true);
+ gs_inrange_node = node->getChild("gs-in-range", 0, true);
+
nav_id_node = node->getChild("nav-id", 0, true);
id_c1_node = node->getChild("nav-id_asc1", 0, true);
id_c2_node = node->getChild("nav-id_asc2", 0, true);
id_c3_node = node->getChild("nav-id_asc3", 0, true);
id_c4_node = node->getChild("nav-id_asc4", 0, true);
+ node->tie("dme-in-range", SGRawValuePointer<bool>(&_dmeInRange));
+
// gps slaving support
nav_slaved_to_gps_node = node->getChild("slaved-to-gps", 0, true);
gps_cdi_deflection_node = fgGetNode("/instrumentation/gps/cdi-deflection", true);
void
FGNavRadio::bind ()
{
- std::ostringstream temp;
- string branch;
- temp << _num;
- branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
+
}
void
FGNavRadio::unbind ()
{
- std::ostringstream temp;
- string branch;
- temp << _num;
- branch = "/instrumentation/" + _name + "[" + temp.str() + "]";
}
double FGNavRadio::adjustNavRange( double stationElev, double aircraftElev,
double nominalRange )
{
+ if (nominalRange <= 0.0) {
+ nominalRange = FG_NAV_DEFAULT_RANGE;
+ }
+
// extend out actual usable range to be 1.3x the published safe range
const double usability_factor = 1.3;
gs_deflection_node->setDoubleValue( 0.0 );
gs_deflection_deg_node->setDoubleValue(0.0);
gs_deflection_norm_node->setDoubleValue(0.0);
+ gs_inrange_node->setBoolValue( false );
to_flag_node->setBoolValue( false );
from_flag_node->setBoolValue( false );
+
+ _dmeInRange = false;
}
void FGNavRadio::updateReceiver(double dt)
effective_range
= adjustNavRange( nav_elev, pos.getElevationM(), _navaid->get_range() );
}
-
+
double effective_range_m = effective_range * SG_NM_TO_METER;
//////////////////////////////////////////////////////////
}
// CDI deflection
- double r = radial - target_radial;
+ double r = target_radial - radial;
SG_NORMALIZE_RANGE(r, -180.0, 180.0);
- if ( fabs(r) > 90.0 ) {
- r = ( r<0.0 ? -r-180.0 : -r+180.0 );
- }
- r = -r; // reverse, since radial is outbound
- _cdiDeflection = r;
if ( is_loc ) {
- // According to Robin Peel, the ILS is 4x more
- // sensitive than a vor
- // http://www.allstar.fiu.edu/aero/ILS.htm confirms both the 4x sensitvity
- // increase, and also the 'full-deflection is 10-degrees for a VOR' clamp
- _cdiDeflection *= 4.0;
- }
+ if (_falseCoursesEnabled) {
+ // The factor of 30.0 gives a period of 120 which gives us 3 cycles and six
+ // zeros i.e. six courses: one front course, one back course, and four
+ // false courses. Three of the six are reverse sensing.
+ _cdiDeflection = 30.0 * sawtooth(r / 30.0);
+ } else {
+ // no false courses, but we do need to create a back course
+ if (fabs(r) > 90.0) { // front course
+ _cdiDeflection = r - copysign(180.0, r);
+ } else {
+ _cdiDeflection = r; // back course
+ }
+
+ _cdiDeflection = -_cdiDeflection; // reverse for outbound radial
+ } // of false courses disabled
+
+ const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
+ _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
+
+ if (backcourse_node->getBoolValue()) {
+ _cdiDeflection = -_cdiDeflection;
+ }
+ } else {
+ // handle the TO side of the VOR
+ if (fabs(r) > 90.0) {
+ r = ( r<0.0 ? -r-180.0 : -r+180.0 );
+ }
+ _cdiDeflection = r;
+ } // of non-localiser case
+
SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
_cdiDeflection *= signal_quality_norm;
_cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
updateGlideSlope(dt, aircraft, signal_quality_norm);
+ updateDME(aircraft);
last_loc_dist = loc_dist;
}
void FGNavRadio::updateGlideSlope(double dt, const SGVec3d& aircraft, double signal_quality_norm)
{
+ _gsNeedleDeflection = 0.0;
if (!_gs || !inrange_node->getBoolValue()) {
gs_dist_node->setDoubleValue( 0.0 );
+ gs_inrange_node->setBoolValue(false);
return;
}
- // find closest distance to the gs base line
- double dist = sgdClosestPointToLineDistSquared(aircraft.data(), _gs->cart().data(),
- gs_base_vec.data());
- dist = sqrt(dist);
- gs_dist_node->setDoubleValue(dist);
- double heightAboveStationM =
- (alt_node->getDoubleValue() - _gs->elevation()) * SG_FEET_TO_METER;
+ double gsDist = dist(aircraft, _gsCart);
+ gs_dist_node->setDoubleValue(gsDist);
+ bool gsInRange = (gsDist < (_gs->get_range() * SG_NM_TO_METER));
+ gs_inrange_node->setBoolValue(gsInRange);
+
+ if (!gsInRange) {
+ return;
+ }
- //////////////////////////////////////////////////////////
- // compute the amount of glide slope needle deflection
- // (.i.e. the number of degrees we are off the glide slope * 5.0
- //
- // CLO - 13 Mar 2006: The glide slope needle should peg at
- // +/-0.7 degrees off the ideal glideslope. I'm not sure why
- // we compute the factor the way we do (5*gs_error), but we
- // need to compensate for our 'odd' number in the glideslope
- // needle animation. This means that the needle should peg
- // when this values is +/-3.5.
- //////////////////////////////////////////////////////////
- double angle = atan2(heightAboveStationM, dist) * SGD_RADIANS_TO_DEGREES;
+ SGVec3d pos = aircraft - _gsCart; // relative vector from gs antenna to aircraft
+ // The positive GS axis points along the runway in the landing direction,
+ // toward the far end, not toward the approach area, so we need a - sign here:
+ double dot_h = -dot(pos, _gsAxis);
+ double dot_v = dot(pos, _gsVertical);
+ double angle = atan2(dot_v, dot_h) * SGD_RADIANS_TO_DEGREES;
double deflectionAngle = target_gs - angle;
- //SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
+
+ if (_falseCoursesEnabled) {
+ // Construct false glideslopes. The scale factor of 1.5
+ // in the sawtooth gives a period of 6 degrees.
+ // There will be zeros at 3, 6r, 9, 12r et cetera
+ // where "r" indicates reverse sensing.
+ // This is is consistent with conventional pilot lore
+ // e.g. http://www.allstar.fiu.edu/aerojava/ILS.htm
+ // but inconsistent with
+ // http://www.freepatentsonline.com/3757338.html
+ //
+ // It may be that some of each exist.
+ if (deflectionAngle < 0) {
+ deflectionAngle = 1.5 * sawtooth(deflectionAngle / 1.5);
+ } else {
+ // no false GS below the true GS
+ }
+ }
+
_gsNeedleDeflection = deflectionAngle * 5.0;
_gsNeedleDeflection *= signal_quality_norm;
+
+ SG_CLAMP_RANGE(deflectionAngle, -0.7, 0.7);
_gsNeedleDeflectionNorm = (deflectionAngle / 0.7) * signal_quality_norm;
- SG_CLAMP_RANGE(_gsNeedleDeflectionNorm, -1.0, 1.0);
//////////////////////////////////////////////////////////
// Calculate desired rate of climb for intercepting the GS
double des_angle = angle - 10 * gs_diff;
// estimate horizontal speed towards ILS in meters per minute
- double elapsedDistance = last_x - dist;
- last_x = dist;
+ double elapsedDistance = last_x - gsDist;
+ last_x = gsDist;
double new_vel = ( elapsedDistance / dt );
horiz_vel = 0.75 * horiz_vel + 0.25 * new_vel;
* horiz_vel * SG_METER_TO_FEET );
}
+void FGNavRadio::updateDME(const SGVec3d& aircraft)
+{
+ if (!_dme || !dme_serviceable_node->getBoolValue()) {
+ _dmeInRange = false;
+ return;
+ }
+
+ double dme_distance = dist(aircraft, _dme->cart());
+ _dmeInRange = (dme_distance < _dme->get_range() * SG_NM_TO_METER);
+}
+
void FGNavRadio::updateGPSSlaved()
{
has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
// play station ident via audio system if on + ident,
// otherwise turn it off
- if (!power_btn_node->getBoolValue()
+ if (!power_btn_node->getBoolValue()
|| !(bus_power_node->getDoubleValue() > 1.0)
|| !ident_btn_node->getBoolValue()
|| !audio_btn_node->getBoolValue() ) {
- globals->get_soundmgr()->stop( nav_fx_name );
- globals->get_soundmgr()->stop( dme_fx_name );
+ _sgr->stop( nav_fx_name );
+ _sgr->stop( dme_fx_name );
return;
}
- SGSoundSample *sound = globals->get_soundmgr()->find( nav_fx_name );
- double vol = vol_btn_node->getDoubleValue();
+ SGSoundSample *sound = _sgr->find( nav_fx_name );
+ double vol = vol_btn_node->getFloatValue();
SG_CLAMP_RANGE(vol, 0.0, 1.0);
if ( sound != NULL ) {
SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-vor-ident sound" );
}
- sound = globals->get_soundmgr()->find( dme_fx_name );
+ sound = _sgr->find( dme_fx_name );
if ( sound != NULL ) {
sound->set_volume( vol );
} else {
SG_LOG( SG_COCKPIT, SG_ALERT, "Can't find nav-dme-ident sound" );
}
-
- if ( last_time < globals->get_time_params()->get_cur_time() - 30 ) {
- last_time = globals->get_time_params()->get_cur_time();
- play_count = 0;
+
+ const int NUM_IDENT_SLOTS = 5;
+ const time_t SLOT_LENGTH = 5; // seconds
+
+ // There are N slots numbered 0 through (NUM_IDENT_SLOTS-1) inclusive.
+ // Each slot is 5 seconds long.
+ // Slots 0 is for DME
+ // the rest are for azimuth.
+ time_t now = globals->get_time_params()->get_cur_time();
+ if ((now >= last_time) && (now < last_time + SLOT_LENGTH)) {
+ return; // wait longer
}
- if ( play_count < 4 ) {
- // play VOR ident
- if ( !globals->get_soundmgr()->is_playing(nav_fx_name) ) {
- globals->get_soundmgr()->play_once( nav_fx_name );
- ++play_count;
+ last_time = now;
+ play_count = ++play_count % NUM_IDENT_SLOTS;
+
+ // Previous ident is out of time; if still playing, cut it off:
+ _sgr->stop( nav_fx_name );
+ _sgr->stop( dme_fx_name );
+ if (play_count == 0) { // the DME slot
+ if (_dmeInRange && dme_serviceable_node->getBoolValue()) {
+ // play DME ident
+ if (vol > 0.05) _sgr->play_once( dme_fx_name );
+ }
+ } else { // NAV slot
+ if (inrange_node->getBoolValue() && nav_serviceable_node->getBoolValue()) {
+ if (vol > 0.05) _sgr->play_once(nav_fx_name);
}
- } else if ( play_count < 5 && has_dme) {
- // play DME ident
- if ( !globals->get_soundmgr()->is_playing(nav_fx_name) &&
- !globals->get_soundmgr()->is_playing(dme_fx_name) ) {
- globals->get_soundmgr()->play_once( dme_fx_name );
- ++play_count;
- }
}
}
_navaid = nav;
char identBuffer[5] = " ";
if (nav) {
- FGNavRecord* dme = globals->get_dmelist()->findByFreq(freq, pos);
- has_dme = (dme != NULL);
+ _dme = globals->get_dmelist()->findByFreq(freq, pos);
nav_id_node->setStringValue(nav->get_ident());
strncpy(identBuffer, nav->ident().c_str(), 5);
if (nav->type() == FGPositioned::VOR) {
target_radial = sel_radial_node->getDoubleValue();
_gs = NULL;
+ has_gs_node->setBoolValue(false);
} else { // ILS or LOC
_gs = globals->get_gslist()->findByFreq(freq, pos);
has_gs_node->setBoolValue(_gs != NULL);
+ _localizerWidth = localizerWidth(nav);
twist = 0.0;
- effective_range = FG_LOC_DEFAULT_RANGE;
+ effective_range = nav->get_range();
target_radial = nav->get_multiuse();
SG_NORMALIZE_RANGE(target_radial, 0.0, 360.0);
int tmp = (int)(_gs->get_multiuse() / 1000.0);
target_gs = (double)tmp / 100.0;
- SGGeod baseLine;
- double dummy;
- SGGeodesy::direct(_gs->geod(), target_radial + 90.0, 100.0, baseLine, dummy);
- gs_base_vec = SGVec3d::fromGeod(baseLine) - _gs->cart();
+ // until penaltyForNav goes away, we cannot assume we always pick
+ // paired LOC/GS trasmsitters. As we pass over a runway threshold, we
+ // often end up picking the 'wrong' LOC, but the correct GS. To avoid
+ // breaking the basis computation, ensure we use the GS radial and not
+ // the (potentially reversed) LOC radial.
+ double gs_radial = fmod(_gs->get_multiuse(), 1000.0);
+ SG_NORMALIZE_RANGE(gs_radial, 0.0, 360.0);
+
+ // GS axis unit tangent vector
+ // (along the runway)
+ _gsCart = _gs->cart();
+ _gsAxis = tangentVector(_gs->geod(), _gsCart, gs_radial);
+
+ // GS baseline unit tangent vector
+ // (perpendicular to the runay along the ground)
+ SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, gs_radial + 90.0);
+ _gsVertical = cross(baseline, _gsAxis);
} // of have glideslope
} // of found LOC or ILS
audioNavidChanged();
} else { // found nothing
_gs = NULL;
+ _dme = NULL;
nav_id_node->setStringValue("");
- has_dme = false;
- globals->get_soundmgr()->remove( nav_fx_name );
- globals->get_soundmgr()->remove( dme_fx_name );
+
+ _sgr->remove( nav_fx_name );
+ _sgr->remove( dme_fx_name );
}
is_valid_node->setBoolValue(nav != NULL);
id_c4_node->setIntValue( (int)identBuffer[3] );
}
+double FGNavRadio::localizerWidth(FGNavRecord* aLOC)
+{
+ FGRunway* rwy = aLOC->runway();
+ assert(rwy);
+
+ SGVec3d thresholdCart(SGVec3d::fromGeod(rwy->threshold()));
+ double axisLength = dist(aLOC->cart(), thresholdCart);
+ double landingLength = dist(thresholdCart, SGVec3d::fromGeod(rwy->end()));
+
+// Reference: http://dcaa.slv.dk:8000/icaodocs/
+// ICAO standard width at threshold is 210 m = 689 feet = approx 700 feet.
+// ICAO 3.1.1 half course = DDM = 0.0775
+// ICAO 3.1.3.7.1 Sensitivity 0.00145 DDM/m at threshold
+// implies peg-to-peg of 214 m ... we will stick with 210.
+// ICAO 3.1.3.7.1 "Course sector angle shall not exceed 6 degrees."
+
+// Very short runway: less than 1200 m (4000 ft) landing length:
+ if (landingLength < 1200.0) {
+// ICAO fudges localizer sensitivity for very short runways.
+// This produces a non-monotonic sensitivity-versus length relation.
+ axisLength += 1050.0;
+ }
+
+// Example: very short: San Diego KMYF (Montgomery Field) ILS RWY 28R
+// Example: short: Tom's River KMJX (Robert J. Miller) ILS RWY 6
+// Example: very long: Denver KDEN (Denver) ILS RWY 16R
+ double raw_width = 210.0 / axisLength * SGD_RADIANS_TO_DEGREES;
+ return raw_width < 6.0? raw_width : 6.0;
+}
+
void FGNavRadio::audioNavidChanged()
{
- if ( globals->get_soundmgr()->exists(nav_fx_name)) {
- globals->get_soundmgr()->remove(nav_fx_name);
+ if (_sgr->exists(nav_fx_name)) {
+ _sgr->remove(nav_fx_name);
}
try {
string trans_ident(_navaid->get_trans_ident());
SGSoundSample* sound = morse.make_ident(trans_ident, LO_FREQUENCY);
sound->set_volume( 0.3 );
- if (!globals->get_soundmgr()->add( sound, nav_fx_name )) {
+ if (!_sgr->add( sound, nav_fx_name )) {
SG_LOG(SG_COCKPIT, SG_WARN, "Failed to add v1-vor-ident sound");
}
- if ( globals->get_soundmgr()->exists( dme_fx_name ) ) {
- globals->get_soundmgr()->remove( dme_fx_name );
+ if ( _sgr->exists( dme_fx_name ) ) {
+ _sgr->remove( dme_fx_name );
}
sound = morse.make_ident( trans_ident, HI_FREQUENCY );
sound->set_volume( 0.3 );
- globals->get_soundmgr()->add( sound, dme_fx_name );
+ _sgr->add( sound, dme_fx_name );
int offset = (int)(sg_random() * 30.0);
play_count = offset / 4;
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