# 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);
+}
+
// Constructor
FGNavRadio::FGNavRadio(SGPropertyNode *node) :
lon_node(fgGetNode("/position/longitude-deg", true)),
inrange_node(NULL),
signal_quality_norm_node(NULL),
cdi_deflection_node(NULL),
+ cdi_deflection_norm_node(NULL),
cdi_xtrack_error_node(NULL),
cdi_xtrack_hdg_err_node(NULL),
has_gs_node(NULL),
loc_node(NULL),
loc_dist_node(NULL),
gs_deflection_node(NULL),
+ gs_deflection_deg_node(NULL),
+ gs_deflection_norm_node(NULL),
gs_rate_of_climb_node(NULL),
gs_dist_node(NULL),
nav_id_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)
inrange_node = node->getChild("in-range", 0, true);
signal_quality_norm_node = node->getChild("signal-quality-norm", 0, true);
cdi_deflection_node = node->getChild("heading-needle-deflection", 0, true);
+ cdi_deflection_norm_node = node->getChild("heading-needle-deflection-norm", 0, true);
cdi_xtrack_error_node = node->getChild("crosstrack-error-m", 0, true);
cdi_xtrack_hdg_err_node
= node->getChild("crosstrack-heading-error-deg", 0, true);
loc_node = node->getChild("nav-loc", 0, true);
loc_dist_node = node->getChild("nav-distance", 0, true);
gs_deflection_node = node->getChild("gs-needle-deflection", 0, true);
+ gs_deflection_deg_node = node->getChild("gs-needle-deflection-deg", 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);
nav_id_node = node->getChild("nav-id", 0, true);
void
FGNavRadio::update(double dt)
{
- // Do a nav station search only once a second to reduce
- // unnecessary work. (Also, make sure to do this before caching
- // any values!)
- _time_before_search_sec -= dt;
- if ( _time_before_search_sec < 0 ) {
- search();
+ if (dt <= 0.0) {
+ return; // paused
}
-
- bool inrange = false;
-
+
// Create "formatted" versions of the nav frequencies for
// instrument displays.
char tmp[16];
sprintf( tmp, "%.2f", alt_freq_node->getDoubleValue() );
fmt_alt_freq_node->setStringValue(tmp);
- if (_navaid
- && power_btn_node->getBoolValue()
+ if (power_btn_node->getBoolValue()
&& (bus_power_node->getDoubleValue() > 1.0)
&& nav_serviceable_node->getBoolValue() )
{
- inrange = updateWithPower(dt);
+ if (nav_slaved_to_gps_node->getBoolValue()) {
+ updateGPSSlaved();
+ } else {
+ updateReceiver(dt);
+ }
+
+ updateCDI(dt);
} else {
- inrange_node->setBoolValue( false );
- cdi_deflection_node->setDoubleValue( 0.0 );
- cdi_xtrack_error_node->setDoubleValue( 0.0 );
- cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
- time_to_intercept->setDoubleValue( 0.0 );
- gs_deflection_node->setDoubleValue( 0.0 );
- to_flag_node->setBoolValue( false );
- from_flag_node->setBoolValue( false );
+ clearOutputs();
}
-
- updateAudio(inrange);
+
+ updateAudio();
}
-bool FGNavRadio::updateWithPower(double dt)
+void FGNavRadio::clearOutputs()
{
- bool nav_serviceable = nav_serviceable_node->getBoolValue();
- bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
- bool tofrom_serviceable = tofrom_serviceable_node->getBoolValue();
-
- double az1, az2, s;
+ inrange_node->setBoolValue( false );
+ cdi_deflection_node->setDoubleValue( 0.0 );
+ cdi_deflection_norm_node->setDoubleValue( 0.0 );
+ cdi_xtrack_error_node->setDoubleValue( 0.0 );
+ cdi_xtrack_hdg_err_node->setDoubleValue( 0.0 );
+ time_to_intercept->setDoubleValue( 0.0 );
+ gs_deflection_node->setDoubleValue( 0.0 );
+ gs_deflection_deg_node->setDoubleValue(0.0);
+ gs_deflection_norm_node->setDoubleValue(0.0);
+ to_flag_node->setBoolValue( false );
+ from_flag_node->setBoolValue( false );
+}
+
+void FGNavRadio::updateReceiver(double dt)
+{
+ // Do a nav station search only once a second to reduce
+ // unnecessary work. (Also, make sure to do this before caching
+ // any values!)
+ _time_before_search_sec -= dt;
+ if ( _time_before_search_sec < 0 ) {
+ search();
+ }
+
+ if (!_navaid) {
+ _cdiDeflection = 0.0;
+ _cdiCrossTrackErrorM = 0.0;
+ _toFlag = _fromFlag = false;
+ _gsNeedleDeflection = 0.0;
+ _gsNeedleDeflectionNorm = 0.0;
+ inrange_node->setBoolValue(false);
+ return;
+ }
+
SGGeod pos = SGGeod::fromDegFt(lon_node->getDoubleValue(),
lat_node->getDoubleValue(),
alt_node->getDoubleValue());
-
- bool inrange = false;
- if ( nav_slaved_to_gps_node->getBoolValue() ) {
- // FIXME - GPS-slaved GS support in unfinished
- has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
- inrange = gps_to_flag_node->getBoolValue() || gps_from_flag_node->getBoolValue();
- } else {
- inrange = inrange_node->getBoolValue();
- }
-
+
double nav_elev = _navaid->get_elev_ft();
SGVec3d aircraft = SGVec3d::fromGeod(pos);
double loc_dist = dist(aircraft, _navaid->cart());
loc_dist_node->setDoubleValue( loc_dist );
bool is_loc = loc_node->getBoolValue();
double signal_quality_norm = signal_quality_norm_node->getDoubleValue();
-
- if (_gs) {
- // find closest distance to the gs base line
- double dist = sgdClosestPointToLineDistSquared(aircraft.data(), _gs->cart().data(),
- gs_base_vec.data());
- gs_dist_node->setDoubleValue( sqrt( dist ) );
- // cout << "gs_dist = " << gs_dist_node->getDoubleValue()
- // << endl;
-
- // wgs84 heading to glide slope (to determine sign of distance)
- SGGeodesy::inverse(pos, _gs->geod(), az1, az2, s);
- double r = az1 - target_radial;
- SG_NORMALIZE_RANGE(r, -180.0, 180.0);
- if (fabs(r) <= 90.0) {
- gs_dist_signed = gs_dist_node->getDoubleValue();
- } else {
- gs_dist_signed = -gs_dist_node->getDoubleValue();
- }
- } else {
- gs_dist_node->setDoubleValue( 0.0 );
- }
-
+
+ double az2, s;
//////////////////////////////////////////////////////////
// compute forward and reverse wgs84 headings to localizer
//////////////////////////////////////////////////////////
double hdg;
SGGeodesy::inverse(pos, _navaid->geod(), hdg, az2, s);
- heading_node->setDoubleValue( hdg );
+ heading_node->setDoubleValue(hdg);
double radial = az2 - twist;
double recip = radial + 180.0;
SG_NORMALIZE_RANGE(recip, 0.0, 360.0);
radial_node->setDoubleValue( radial );
recip_radial_node->setDoubleValue( recip );
-
+
//////////////////////////////////////////////////////////
// compute the target/selected radial in "true" heading
//////////////////////////////////////////////////////////
signal_quality_norm, dt );
signal_quality_norm_node->setDoubleValue( signal_quality_norm );
- if ( ! nav_slaved_to_gps_node->getBoolValue() ) {
- /* not slaved to gps */
- inrange = signal_quality_norm > 0.2;
- }
+ bool inrange = signal_quality_norm > 0.2;
inrange_node->setBoolValue( inrange );
-
+
//////////////////////////////////////////////////////////
// compute to/from flag status
//////////////////////////////////////////////////////////
- if (tofrom_serviceable) {
- if (nav_slaved_to_gps_node->getBoolValue()) {
- to_flag_node->setBoolValue(gps_to_flag_node->getBoolValue());
- from_flag_node->setBoolValue(gps_from_flag_node->getBoolValue());
- } else if (inrange) {
- bool toFlag = false;
- if (is_loc) {
- toFlag = true;
- } else {
- double offset = fabs(radial - target_radial);
- toFlag = (offset > 90.0 && offset < 270.0);
- }
-
- to_flag_node->setBoolValue(toFlag);
- from_flag_node->setBoolValue(!toFlag);
- } else { // out-of-range
- to_flag_node->setBoolValue(false);
- from_flag_node->setBoolValue(false);
+ if (inrange) {
+ if (is_loc) {
+ _toFlag = true;
+ } else {
+ double offset = fabs(radial - target_radial);
+ _toFlag = (offset > 90.0 && offset < 270.0);
}
+ _fromFlag = !_toFlag;
} else {
- to_flag_node->setBoolValue(false);
- from_flag_node->setBoolValue(false);
+ _toFlag = _fromFlag = false;
}
- //////////////////////////////////////////////////////////
- // compute the deflection of the CDI needle, clamped to the range
- // of ( -10 , 10 )
- //////////////////////////////////////////////////////////
- double r = 0.0;
- bool loc_backside = false; // an in-code flag indicating that we are
- // on a localizer backcourse.
- if ( cdi_serviceable ) {
- if ( nav_slaved_to_gps_node->getBoolValue() ) {
- r = gps_cdi_deflection_node->getDoubleValue();
- // We want +- 5 dots deflection for the gps, so clamp
- // to -12.5/12.5
- SG_CLAMP_RANGE( r, -12.5, 12.5 );
- } else if ( inrange ) {
- r = radial - target_radial;
- // cout << "Target radial = " << target_radial
- // << " Actual radial = " << radial << endl;
-
- SG_NORMALIZE_RANGE(r, -180.0, 180.0);
- if ( fabs(r) > 90.0 ) {
- r = ( r<0.0 ? -r-180.0 : -r+180.0 );
- } else {
- if (is_loc) {
- loc_backside = true;
- }
- }
-
- r = -r; // reverse, since radial is outbound
- if ( is_loc ) {
- // According to Robin Peel, the ILS is 4x more
- // sensitive than a vor
- r *= 4.0;
- }
- SG_CLAMP_RANGE( r, -10.0, 10.0 );
- r *= signal_quality_norm;
+ // CDI deflection
+ double r = target_radial - radial;
+ SG_NORMALIZE_RANGE(r, -180.0, 180.0);
+
+ if ( is_loc ) {
+ // 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);
+ const double VOR_FULL_ARC = 20.0; // VOR is -10 .. 10 degree swing
+ _cdiDeflection *= VOR_FULL_ARC / _localizerWidth; // increased localiser sensitivity
+ } else {
+ // handle the TO side of the VOR
+ if (fabs(r) > 90.0) {
+ r = ( r<0.0 ? -r-180.0 : -r+180.0 );
}
- }
- cdi_deflection_node->setDoubleValue( r );
+ _cdiDeflection = r;
+ } // of non-localiser case
+
+ SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
+ _cdiDeflection *= signal_quality_norm;
+
+ // cross-track error (in metres)
+ _cdiCrossTrackErrorM = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
+
+ updateGlideSlope(dt, aircraft, signal_quality_norm);
+
+ 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 );
+ return;
+ }
+
+ double gsDist = dist(aircraft, _gsCart);
+ gs_dist_node->setDoubleValue(gsDist);
+ if (gsDist > (_gs->get_range() * SG_NM_TO_METER)) {
+ return;
+ }
+
+ 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;
+
+ // 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;
+
//////////////////////////////////////////////////////////
- // compute the amount of cross track distance error in meters
+ // Calculate desired rate of climb for intercepting the GS
//////////////////////////////////////////////////////////
- double xtrack_error = 0.0;
- if ( inrange && nav_serviceable && cdi_serviceable ) {
- r = radial - target_radial;
- SG_NORMALIZE_RANGE(r, -180.0, 180.0);
- if ( fabs(r) > 90.0 ) {
- r = ( r<0.0 ? -r-180.0 : -r+180.0 );
- }
+ double gs_diff = target_gs - angle;
+ // convert desired vertical path angle into a climb rate
+ double des_angle = angle - 10 * gs_diff;
- r = -r; // reverse, since radial is outbound
+ // estimate horizontal speed towards ILS in meters per minute
+ double elapsedDistance = last_x - gsDist;
+ last_x = gsDist;
+
+ double new_vel = ( elapsedDistance / dt );
+ horiz_vel = 0.75 * horiz_vel + 0.25 * new_vel;
- xtrack_error = loc_dist * sin(r * SGD_DEGREES_TO_RADIANS);
+ gs_rate_of_climb_node
+ ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
+ * horiz_vel * SG_METER_TO_FEET );
+}
+
+void FGNavRadio::updateGPSSlaved()
+{
+ has_gs_node->setBoolValue(gps_has_gs_node->getBoolValue());
+
+ _toFlag = gps_to_flag_node->getBoolValue();
+ _fromFlag = gps_from_flag_node->getBoolValue();
+
+ inrange_node->setBoolValue(_toFlag | _fromFlag);
+
+ _cdiDeflection = gps_cdi_deflection_node->getDoubleValue();
+ // clmap to some range (+/- 10 degrees) as the regular deflection
+ SG_CLAMP_RANGE(_cdiDeflection, -10.0, 10.0 );
+
+ _cdiCrossTrackErrorM = 0.0; // FIXME, supply this
+ _gsNeedleDeflection = 0.0; // FIXME, supply this
+}
+
+void FGNavRadio::updateCDI(double dt)
+{
+ bool cdi_serviceable = cdi_serviceable_node->getBoolValue();
+ bool inrange = inrange_node->getBoolValue();
+
+ if (tofrom_serviceable_node->getBoolValue()) {
+ to_flag_node->setBoolValue(_toFlag);
+ from_flag_node->setBoolValue(_fromFlag);
} else {
- xtrack_error = 0.0;
+ to_flag_node->setBoolValue(false);
+ from_flag_node->setBoolValue(false);
+ }
+
+ if (!cdi_serviceable) {
+ _cdiDeflection = 0.0;
+ _cdiCrossTrackErrorM = 0.0;
}
- cdi_xtrack_error_node->setDoubleValue( xtrack_error );
+
+ cdi_deflection_node->setDoubleValue(_cdiDeflection);
+ cdi_deflection_norm_node->setDoubleValue(_cdiDeflection * 0.1);
+ cdi_xtrack_error_node->setDoubleValue(_cdiCrossTrackErrorM);
//////////////////////////////////////////////////////////
// compute an approximate ground track heading error
//////////////////////////////////////////////////////////
double hdg_error = 0.0;
if ( inrange && cdi_serviceable ) {
- double vn = fgGetDouble( "/velocities/speed-north-fps" );
- double ve = fgGetDouble( "/velocities/speed-east-fps" );
- double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
- if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
+ double vn = fgGetDouble( "/velocities/speed-north-fps" );
+ double ve = fgGetDouble( "/velocities/speed-east-fps" );
+ double gnd_trk_true = atan2( ve, vn ) * SGD_RADIANS_TO_DEGREES;
+ if ( gnd_trk_true < 0.0 ) { gnd_trk_true += 360.0; }
- SGPropertyNode *true_hdg
- = fgGetNode("/orientation/heading-deg", true);
- hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
+ SGPropertyNode *true_hdg
+ = fgGetNode("/orientation/heading-deg", true);
+ hdg_error = gnd_trk_true - true_hdg->getDoubleValue();
- // cout << "ground track = " << gnd_trk_true
- // << " orientation = " << true_hdg->getDoubleValue() << endl;
+ // cout << "ground track = " << gnd_trk_true
+ // << " orientation = " << true_hdg->getDoubleValue() << endl;
}
cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
- //////////////////////////////////////////////////////////
- // compute the time to intercept selected radial (based on
- // current and last cross track errors and dt
- //////////////////////////////////////////////////////////
- if (dt > 0) { // Are we paused?
- double t = 0.0;
- if ( inrange && cdi_serviceable ) {
- double xrate_ms = (last_xtrack_error - xtrack_error) / dt;
- if ( fabs(xrate_ms) > 0.00001 ) {
- t = xtrack_error / xrate_ms;
- } else {
- t = 9999.9;
- }
- }
- time_to_intercept->setDoubleValue( t );
- }
-
- //////////////////////////////////////////////////////////
- // 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.
- //////////////////////////////////////////////////////////
- r = 0.0;
- if (_gs && gs_serviceable_node->getBoolValue() ) {
- if ( nav_slaved_to_gps_node->getBoolValue() ) {
- // FIXME what should be set here?
- } else if ( inrange ) {
- double x = gs_dist_node->getDoubleValue();
- double y = (alt_node->getDoubleValue() - nav_elev)
- * SG_FEET_TO_METER;
- // cout << "dist = " << x << " height = " << y << endl;
- double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
- r = (target_gs - angle) * 5.0;
- r *= signal_quality_norm;
- }
- }
- gs_deflection_node->setDoubleValue( r );
-
- //////////////////////////////////////////////////////////
- // Calculate desired rate of climb for intercepting the GS
- //////////////////////////////////////////////////////////
- double x = gs_dist_node->getDoubleValue();
- double y = (alt_node->getDoubleValue() - nav_elev)
- * SG_FEET_TO_METER;
- double current_angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
-
- double target_angle = target_gs;
- double gs_diff = target_angle - current_angle;
-
- // convert desired vertical path angle into a climb rate
- double des_angle = current_angle - 10 * gs_diff;
-
- // estimate horizontal speed towards ILS in meters per minute
- double dist = last_x - x;
- last_x = x;
- if ( dt > 0.0 ) {
- // avoid nan
- double new_vel = ( dist / dt );
-
- horiz_vel = 0.75 * horiz_vel + 0.25 * new_vel;
- // double horiz_vel = cur_fdm_state->get_V_ground_speed()
- // * SG_FEET_TO_METER * 60.0;
- // double horiz_vel = airspeed_node->getFloatValue()
- // * SG_FEET_TO_METER * 60.0;
-
- gs_rate_of_climb_node
- ->setDoubleValue( -sin( des_angle * SGD_DEGREES_TO_RADIANS )
- * horiz_vel * SG_METER_TO_FEET );
- }
-
//////////////////////////////////////////////////////////
// Calculate a suggested target heading to smoothly intercept
// a nav/ils radial.
// The cdi deflection should be +/-10 for a full range of deflection
// so multiplying this by 3 gives us +/- 30 degrees heading
// compensation.
- double adjustment = cdi_deflection_node->getDoubleValue() * 3.0;
+ double adjustment = _cdiDeflection * 3.0;
SG_CLAMP_RANGE( adjustment, -30.0, 30.0 );
// determine the target heading to fly to intercept the
// tgt_radial = target radial (true) + cdi offset adjustmest -
// xtrack heading error adjustment
double nta_hdg;
- if ( is_loc && backcourse_node->getBoolValue() ) {
+ double trtrue = target_radial_true_node->getDoubleValue();
+ if ( loc_node->getBoolValue() && backcourse_node->getBoolValue() ) {
// tuned to a localizer and backcourse mode activated
trtrue += 180.0; // reverse the target localizer heading
- while ( trtrue > 360.0 ) { trtrue -= 360.0; }
+ SG_NORMALIZE_RANGE(trtrue, 0.0, 360.0);
nta_hdg = trtrue - adjustment - hdg_error;
} else {
nta_hdg = trtrue + adjustment - hdg_error;
}
- while ( nta_hdg < 0.0 ) { nta_hdg += 360.0; }
- while ( nta_hdg >= 360.0 ) { nta_hdg -= 360.0; }
+ SG_NORMALIZE_RANGE(nta_hdg, 0.0, 360.0);
target_auto_hdg_node->setDoubleValue( nta_hdg );
- last_xtrack_error = xtrack_error;
- last_loc_dist = loc_dist;
- return inrange;
+ //////////////////////////////////////////////////////////
+ // compute the time to intercept selected radial (based on
+ // current and last cross track errors and dt
+ //////////////////////////////////////////////////////////
+ double t = 0.0;
+ if ( inrange && cdi_serviceable ) {
+ double xrate_ms = (last_xtrack_error - _cdiCrossTrackErrorM) / dt;
+ if ( fabs(xrate_ms) > 0.00001 ) {
+ t = _cdiCrossTrackErrorM / xrate_ms;
+ } else {
+ t = 9999.9;
+ }
+ }
+ time_to_intercept->setDoubleValue( t );
+
+ if (!gs_serviceable_node->getBoolValue() ) {
+ _gsNeedleDeflection = 0.0;
+ _gsNeedleDeflectionNorm = 0.0;
+ }
+ gs_deflection_node->setDoubleValue(_gsNeedleDeflection);
+ gs_deflection_deg_node->setDoubleValue(_gsNeedleDeflectionNorm * 0.7);
+ gs_deflection_norm_node->setDoubleValue(_gsNeedleDeflectionNorm);
+
+ last_xtrack_error = _cdiCrossTrackErrorM;
}
-void FGNavRadio::updateAudio(bool aInRange)
+void FGNavRadio::updateAudio()
{
- if (!_navaid || !aInRange || !nav_serviceable_node->getBoolValue()) {
+ if (!_navaid || !inrange_node->getBoolValue() || !nav_serviceable_node->getBoolValue()) {
return;
}
_gs = NULL;
} else { // ILS or LOC
_gs = globals->get_gslist()->findByFreq(freq, pos);
+ _localizerWidth = localizerWidth(nav);
has_gs_node->setBoolValue(_gs != NULL);
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();
+ // GS axis unit tangent vector
+ // (along the runway)
+ _gsCart = _gs->cart();
+ _gsAxis = tangentVector(_gs->geod(), _gsCart, target_radial);
+
+ // GS baseline unit tangent vector
+ // (perpendicular to the runay along the ground)
+ SGVec3d baseline = tangentVector(_gs->geod(), _gsCart, target_radial + 90.0);
+ _gsVertical = cross(baseline, _gsAxis);
} // of have glideslope
} // of found LOC or ILS
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)) {
projects / flightgear.git / blobdiff