# include <config.h>
#endif
-#if defined( FG_HAVE_NATIVE_SGI_COMPILERS )
-# include <iostream.h>
-#else
-# include <iostream>
-#endif
+#include <simgear/compiler.h>
+
+#include STL_IOSTREAM
#include <simgear/constants.h>
-#include <simgear/math/fg_types.hxx>
-#include <Main/options.hxx>
-#include <Main/bfi.hxx>
+#include <simgear/math/sg_types.hxx>
+#include <simgear/misc/props.hxx>
+#include <Aircraft/aircraft.hxx>
-FG_USING_NAMESPACE(std);
+SG_USING_NAMESPACE(std);
#include "radiostack.hxx"
#include "steam.hxx"
+static bool isTied = false;
+
\f
////////////////////////////////////////////////////////////////////////
// Declare the functions that read the variables
////////////////////////////////////////////////////////////////////////
-// Anything that reads the BFI directly is not implemented at all!
-
-
-#define VARY_E (14)
-
-
double FGSteam::the_STATIC_inhg = 29.92;
-double FGSteam::the_ALT_ft = 0.0;
+double FGSteam::the_ALT_ft = 0.0; // Indicated altitude
double FGSteam::get_ALT_ft() { _CatchUp(); return the_ALT_ft; }
-double FGSteam::get_ASI_kias() { return FGBFI::getAirspeed(); }
+double FGSteam::the_ALT_datum_mb = 1013.0;
+double FGSteam::get_ALT_datum_mb() { return the_ALT_datum_mb; }
+
+void FGSteam::set_ALT_datum_mb ( double datum_mb ) {
+ the_ALT_datum_mb = datum_mb;
+}
+
+double FGSteam::get_ASI_kias() { return fgGetDouble("/velocities/airspeed-kt"); }
double FGSteam::the_VSI_case = 29.92;
double FGSteam::the_VSI_fps = 0.0;
double FGSteam::the_VACUUM_inhg = 0.0;
double FGSteam::get_VACUUM_inhg() { _CatchUp(); return the_VACUUM_inhg; }
-double FGSteam::get_MH_deg () {
- return FGBFI::getHeading () - FGBFI::getMagVar ();
-}
-double FGSteam::get_DG_deg () {
- return FGBFI::getHeading () - FGBFI::getMagVar ();
+double FGSteam::the_MH_err = 0.0;
+double FGSteam::the_MH_deg = 0.0;
+double FGSteam::the_MH_degps = 0.0;
+double FGSteam::get_MH_deg () { _CatchUp(); return the_MH_deg; }
+
+double FGSteam::the_DG_err = 0.0;
+double FGSteam::the_DG_deg = 0.0;
+double FGSteam::the_DG_degps = 0.0;
+double FGSteam::the_DG_inhg = 0.0;
+double FGSteam::get_DG_deg () { _CatchUp(); return the_DG_deg; }
+double FGSteam::get_DG_err () { _CatchUp(); return the_DG_err; }
+
+void FGSteam::set_DG_err ( double approx_magvar ) {
+ the_DG_err = approx_magvar;
}
-double FGSteam::get_TC_rad () { return FGBFI::getSideSlip (); }
-double FGSteam::get_TC_radps () { return FGBFI::getRoll (); }
+double FGSteam::the_TC_rad = 0.0;
+double FGSteam::the_TC_std = 0.0;
+double FGSteam::get_TC_rad () { _CatchUp(); return the_TC_rad; }
+double FGSteam::get_TC_std () { _CatchUp(); return the_TC_std; }
\f
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
-int FGSteam::_UpdatesPending = 9999; /* Forces filter to reset */
+int FGSteam::_UpdatesPending = 1000000; /* Forces filter to reset */
+
+ // FIXME: no need to use static
+ // functions any longer.
void FGSteam::update ( int timesteps )
{
- _UpdatesPending += timesteps;
+ if (!isTied) {
+ isTied = true;
+ fgTie("/steam/airspeed-kt", FGSteam::get_ASI_kias);
+ fgSetArchivable("/steam/airspeed-kt");
+ fgTie("/steam/altitude-ft", FGSteam::get_ALT_ft);
+ fgSetArchivable("/steam/altitude-ft");
+ fgTie("/steam/altimeter-datum-mb",
+ FGSteam::get_ALT_datum_mb, FGSteam::set_ALT_datum_mb,
+ false); /* don't modify the value */
+ fgSetArchivable("/steam/altimeter-datum-mb");
+ fgTie("/steam/turn-rate", FGSteam::get_TC_std);
+ fgSetArchivable("/steam/turn-rate");
+ fgTie("/steam/slip-skid", FGSteam::get_TC_rad);
+ fgSetArchivable("/steam/slip-skid");
+ fgTie("/steam/vertical-speed-fpm", FGSteam::get_VSI_fps);
+ fgSetArchivable("/steam/vertical-speed-fpm");
+ fgTie("/steam/gyro-compass-deg", FGSteam::get_DG_deg);
+ fgSetArchivable("/steam/gyro-compass-deg");
+ fgTie("/steam/adf-deg", FGSteam::get_HackADF_deg);
+ fgSetArchivable("/steam/adf-deg");
+ fgTie("/steam/gyro-compass-error-deg",
+ FGSteam::get_DG_err, FGSteam::set_DG_err,
+ false); /* don't modify the value */
+ fgSetArchivable("/steam/gyro-compass-error-deg");
+ fgTie("/steam/mag-compass-deg", FGSteam::get_MH_deg);
+ fgSetArchivable("/steam/mag-compass-deg");
+ }
+ _UpdatesPending += timesteps;
}
+/* tc should be (elapsed_time_between_updates / desired_smoothing_time) */
void FGSteam::set_lowpass ( double *outthe, double inthe, double tc )
{
if ( tc < 0.0 )
}
} else
if ( tc < 0.2 )
- { /* Normal mode of operation */
+ { /* Normal mode of operation; fast approximation to exp(-tc) */
(*outthe) = (*outthe) * ( 1.0 - tc )
+ inthe * tc;
} else
}
+#define INHG_TO_MB 33.86388 /* Inches_of_mercury * INHG_TO_MB == millibars. */
+
+// Convert air pressure to altitude by ICAO Standard Atmosphere
+double pressInHgToAltFt(double p_inhg)
+{
+ // Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm
+ const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb)
+ const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units.
+ const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km)
+
+ if (p_inhg > p_Tr) // 0.0 to 11.0 km
+ return (1.0 - pow((p_inhg / P_0), 1.0 / 5.2558797)) / 6.8755856e-6;
+ return h_Tr + log10(p_inhg / p_Tr) / -4.806346e-5; // 11.0 to 20.0 km
+ // We could put more code for higher altitudes here.
+}
+
+
+// Convert altitude to air pressure by ICAO Standard Atmosphere
+double altFtToPressInHg(double alt_ft)
+{
+ // Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm
+ const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb)
+ const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units.
+ const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km)
+
+ if (alt_ft < h_Tr) // 0.0 to 11.0 km
+ return P_0 * pow(1.0 - 6.8755856e-6 * alt_ft, 5.2558797);
+ return p_Tr * exp(-4.806346e-5 * (alt_ft - h_Tr)); // 11.0 to 20.0 km
+ // We could put more code for higher altitudes here.
+}
+
+
\f
////////////////////////////////////////////////////////////////////////
// Here the fun really begins
void FGSteam::_CatchUp()
{ if ( _UpdatesPending != 0 )
- { double dt = _UpdatesPending * 1.0 / current_options.get_model_hz();
- int i,j;
+ { double dt = _UpdatesPending * 1.0 /
+ fgGetInt("/sim/model-hz"); // FIXME: inefficient
+ double AccN, AccE, AccU;
+ /* int i, j; */
double d, the_ENGINE_rpm;
- /*
+
+#if 0
+ /**************************
+ There is the possibility that this is the first call.
+ If this is the case, we will emit the feature registrations
+ just to be on the safe side. Doing it more than once will
+ waste CPU time but doesn't hurt anything really.
+ */
+ if ( _UpdatesPending > 999999 )
+ { FGFeature::register_int ( "Avionics/NAV1/Localizer", &NAV1_LOC );
+ FGFeature::register_double ( "Avionics/NAV1/Latitude", &NAV1_Lat );
+ FGFeature::register_double ( "Avionics/NAV1/Longitude", &NAV1_Lon );
+ FGFeature::register_double ( "Avionics/NAV1/Radial", &NAV1_Rad );
+ FGFeature::register_double ( "Avionics/NAV1/Altitude", &NAV1_Alt );
+ FGFeature::register_int ( "Avionics/NAV2/Localizer", &NAV2_LOC );
+ FGFeature::register_double ( "Avionics/NAV2/Latitude", &NAV2_Lat );
+ FGFeature::register_double ( "Avionics/NAV2/Longitude", &NAV2_Lon );
+ FGFeature::register_double ( "Avionics/NAV2/Radial", &NAV2_Rad );
+ FGFeature::register_double ( "Avionics/NAV2/Altitude", &NAV2_Alt );
+ FGFeature::register_double ( "Avionics/ADF/Latitude", &ADF_Lat );
+ FGFeature::register_double ( "Avionics/ADF/Longitude", &ADF_Lon );
+ }
+#endif
+
+ /**************************
Someone has called our update function and
it turns out that we are running somewhat behind.
Here, we recalculate everything for a 'dt' second step.
*/
/**************************
- This is not actually correct, but provides a
- scaling capability for the vacuum pump later on.
- When we have a real engine model, we can ask it.
+ The ball responds to the acceleration vector in the body
+ frame, only the components perpendicular to the longitudinal
+ axis of the aircraft. This is only related to actual
+ side slip for a symmetrical aircraft which is not touching
+ the ground and not changing its attitude. Math simplifies
+ by assuming (for small angles) arctan(x)=x in radians.
+ Obvious failure mode is the absence of liquid in the
+ tube, which is there to damp the motion, so that instead
+ the ball will bounce around, hitting the tube ends.
+ More subtle flaw is having it not move or a travel limit
+ occasionally due to some dirt in the tube or on the ball.
*/
- the_ENGINE_rpm = FGBFI::getThrottle() * 26.0;
+ d = - current_aircraft.fdm_state->get_A_Z_pilot();
+ if ( d < 1 ) d = 1;
+ set_lowpass ( & the_TC_rad,
+ current_aircraft.fdm_state->get_A_Y_pilot () / d,
+ dt );
/**************************
- This is just temporary, until the static source works,
- so we just filter the actual value by one second to
- account for the line impedance of the plumbing.
+ The rate of turn indication is from an electric gyro.
+ We should have it spin up with the master switch.
+ It is mounted at a funny angle so that it detects
+ both rate of bank (i.e. rolling into and out of turns)
+ and the rate of turn (i.e. how fast heading is changing).
*/
- set_lowpass ( & the_ALT_ft, FGBFI::getAltitude(), dt );
+ set_lowpass ( & the_TC_std,
+ current_aircraft.fdm_state->get_Phi_dot ()
+ * SGD_RADIANS_TO_DEGREES / 20.0 +
+ current_aircraft.fdm_state->get_Psi_dot ()
+ * SGD_RADIANS_TO_DEGREES / 3.0 , dt );
+
+ /**************************
+ We want to know the pilot accelerations,
+ to compute the magnetic compass errors.
+ */
+ AccN = current_aircraft.fdm_state->get_V_dot_north();
+ AccE = current_aircraft.fdm_state->get_V_dot_east();
+ AccU = current_aircraft.fdm_state->get_V_dot_down()
+ - 9.81 / 0.3;
+ if ( fabs(the_TC_rad) > 0.2 /* 2.0 */ )
+ { /* Massive sideslip jams it; it stops turning */
+ the_MH_degps = 0.0;
+ the_MH_err = fgGetDouble("/orientation/heading-deg") - the_MH_deg;
+ } else
+ { double MagDip, MagVar, CosDip;
+ double FrcN, FrcE, FrcU, AccTot;
+ double EdgN, EdgE, EdgU;
+ double TrqN, TrqE, TrqU, Torque;
+ /* Find a force vector towards exact magnetic north */
+ MagVar = fgGetDouble("/environment/magnetic-variation-deg")
+ / SGD_RADIANS_TO_DEGREES;
+ MagDip = fgGetDouble("/environment/magnetic-dip-deg")
+ / SGD_RADIANS_TO_DEGREES;
+ CosDip = cos ( MagDip );
+ FrcN = CosDip * cos ( MagVar );
+ FrcE = CosDip * sin ( MagVar );
+ FrcU = sin ( MagDip );
+ /* Rotation occurs around acceleration axis,
+ but axis magnitude is irrelevant. So compute it. */
+ AccTot = AccN*AccN + AccE*AccE + AccU*AccU;
+ if ( AccTot > 1.0 ) AccTot = sqrt ( AccTot );
+ else AccTot = 1.0;
+ /* Force applies to north marking on compass card */
+ EdgN = cos ( the_MH_err / SGD_RADIANS_TO_DEGREES );
+ EdgE = sin ( the_MH_err / SGD_RADIANS_TO_DEGREES );
+ EdgU = 0.0;
+ /* Apply the force to the edge to get torques */
+ TrqN = EdgE * FrcU - EdgU * FrcE;
+ TrqE = EdgU * FrcN - EdgN * FrcU;
+ TrqU = EdgN * FrcE - EdgE * FrcN;
+ /* Select the component parallel to the axis */
+ Torque = ( TrqN * AccN +
+ TrqE * AccE +
+ TrqU * AccU ) * 5.0 / AccTot;
+ /* The magnetic compass has angular momentum,
+ so we apply a torque to it and wait */
+ if ( dt < 1.0 )
+ { the_MH_degps= the_MH_degps * (1.0 - dt) - Torque;
+ the_MH_err += dt * the_MH_degps;
+ }
+ if ( the_MH_err > 180.0 ) the_MH_err -= 360.0; else
+ if ( the_MH_err < -180.0 ) the_MH_err += 360.0;
+ the_MH_deg = fgGetDouble("/orientation/heading-deg") - the_MH_err;
+ }
+
+ /**************************
+ This is not actually correct, but provides a
+ scaling capability for the vacuum pump later on.
+ When we have a real engine model, we can ask it.
+ */
+ the_ENGINE_rpm = globals->get_controls()->get_throttle(0) * 26.0;
/**************************
First, we need to know what the static line is reporting,
which is a whole simulation area in itself. For now, we cheat.
+ We filter the actual value by one second to
+ account for the line impedance of the plumbing.
*/
- the_STATIC_inhg = 29.92;
- i = (int) the_ALT_ft;
- while ( i > 9000 )
- { the_STATIC_inhg *= 0.707;
- i -= 9000;
- }
- the_STATIC_inhg *= ( 1.0 - 0.293 * i / 9000.0 );
+ double static_inhg
+ = altFtToPressInHg(fgGetDouble("/position/altitude-ft"));
+ set_lowpass ( & the_STATIC_inhg, static_inhg, dt );
/*
NO alternate static source error (student feature),
NO slip-induced error, important for C172 for example.
*/
+ /**************************
+ Altimeter.
+ ICAO standard atmosphere MSL pressure is 1013.25 mb, and pressure
+ gradient is about 28 ft per mb at MSL increasing to about 32 at
+ 5000 and 38 at 10000 ft.
+ Standard altimeters apply the subscale offset to the output altitude,
+ not to the input pressure; I don't know exactly what pressure gradient
+ they assume for this. I choose to make it accurate at low altitudes.
+ Remember, we are trying to simulate a real altimeter, not an ideal one.
+ */
+ set_lowpass ( & the_ALT_ft,
+ pressInHgToAltFt(the_STATIC_inhg) +
+ (the_ALT_datum_mb - 1013.25) * 28.0, /* accurate at low alt. */
+ dt * 10 ); /* smoothing time 0.1 s */
+
/**************************
The VSI case is a low-pass filter of the static line pressure.
The instrument reports the difference, scaled to approx ft.
> have it tumble when you exceed the usual pitch or bank limits,
> put in those insidious turning errors ... for now anyway.
*/
+ if ( _UpdatesPending > 999999 )
+ the_DG_err = fgGetDouble("/environment/magnetic-variation-deg");
+ the_DG_degps = 0.01; /* HACK! */
+ if (dt<1.0) the_DG_err += dt * the_DG_degps;
+ the_DG_deg = fgGetDouble("/orientation/heading-deg") - the_DG_err;
/**************************
Finished updates, now clear the timer
*/
_UpdatesPending = 0;
+ } else {
+ // cout << "0 Updates pending" << endl;
}
}
// Everything below is a transient hack; expect it to disappear
////////////////////////////////////////////////////////////////////////
-/* KMYF ILS */
-#define NAV1_LOC (1)
-#define NAV1_Lat ( 32.0 + 48.94/60.0)
-#define NAV1_Lon (-117.0 - 08.37/60.0)
-#define NAV1_Rad 280.0
-#define NAV1_Alt 423
-
-/* MZB stepdown radial */
-#define NAV2_Lat ( 32.0 + 46.93/60.0)
-#define NAV2_Lon (-117.0 - 13.53/60.0)
-#define NAV2_Rad 068.0
-
-/* HAILE intersection */
-#define ADF_Lat ( 32.0 + 46.79/60.0)
-#define ADF_Lon (-117.0 - 02.70/60.0)
-
-
-
-double FGSteam::get_HackGS_deg ()
-{ double x,y,dme;
- if (0==NAV1_LOC) return 0.0;
- y = 60.0 * ( NAV1_Lat - FGBFI::getLatitude () );
- x = 60.0 * ( NAV1_Lon - FGBFI::getLongitude() )
- * cos ( FGBFI::getLatitude () / RAD_TO_DEG );
- dme = x*x + y*y;
- if ( dme > 0.1 ) x = sqrt ( dme ); else x = 0.3;
- y = FGBFI::getAltitude() - NAV1_Alt;
- return 3.0 - (y/x) * 60.0 / 6000.0;
+
+#if 0
+
+double FGSteam::get_HackGS_deg () {
+ if ( current_radiostack->get_nav1_inrange() &&
+ current_radiostack->get_nav1_has_gs() )
+ {
+ double x = current_radiostack->get_nav1_gs_dist();
+ double y = (fgGetDouble("/position/altitude-ft")
+ - current_radiostack->get_nav1_elev())
+ * SG_FEET_TO_METER;
+ double angle = atan2( y, x ) * SGD_RADIANS_TO_DEGREES;
+ return (current_radiostack->get_nav1_target_gs() - angle) * 5.0;
+ } else {
+ return 0.0;
+ }
}
-double FGSteam::get_HackVOR1_deg ()
-{ double r;
- double x,y;
- y = 60.0 * ( NAV1_Lat - FGBFI::getLatitude () );
- x = 60.0 * ( NAV1_Lon - FGBFI::getLongitude() )
- * cos ( FGBFI::getLatitude () / RAD_TO_DEG );
- r = atan2 ( x, y ) * RAD_TO_DEG - NAV1_Rad - FGBFI::getMagVar();
+double FGSteam::get_HackVOR1_deg () {
+ double r;
+
+ if ( current_radiostack->get_nav1_inrange() ) {
+ r = current_radiostack->get_nav1_heading()
+ - current_radiostack->get_nav1_radial();
+ // cout << "Radial = " << current_radiostack->get_nav1_radial()
+ // << " Bearing = " << current_radiostack->get_nav1_heading()
+ // << endl;
+
if (r> 180.0) r-=360.0; else
- if (r<-180.0) r+=360.0;
+ if (r<-180.0) r+=360.0;
if ( fabs(r) > 90.0 )
- r = ( r<0.0 ? -r-180.0 : -r+180.0 );
- if (NAV1_LOC) r*=5.0;
- return r;
+ r = ( r<0.0 ? -r-180.0 : -r+180.0 );
+ // According to Robin Peel, the ILS is 4x more sensitive than a vor
+ if ( current_radiostack->get_nav1_loc() ) r *= 4.0;
+ } else {
+ r = 0.0;
+ }
+
+ return r;
}
-double FGSteam::get_HackVOR2_deg ()
-{ double r;
- double x,y;
- y = 60.0 * ( NAV2_Lat - FGBFI::getLatitude () );
- x = 60.0 * ( NAV2_Lon - FGBFI::getLongitude() )
- * cos ( FGBFI::getLatitude () / RAD_TO_DEG );
- r = atan2 ( x, y ) * RAD_TO_DEG - NAV2_Rad - FGBFI::getMagVar();
+double FGSteam::get_HackVOR2_deg () {
+ double r;
+
+ if ( current_radiostack->get_nav2_inrange() ) {
+ r = current_radiostack->get_nav2_heading()
+ - current_radiostack->get_nav2_radial();
+ // cout << "Radial = " << current_radiostack->get_nav1_radial()
+ // << " Bearing = " << current_radiostack->get_nav1_heading() << endl;
+
if (r> 180.0) r-=360.0; else
- if (r<-180.0) r+=360.0;
+ if (r<-180.0) r+=360.0;
if ( fabs(r) > 90.0 )
- r = ( r<0.0 ? -r-180.0 : -r+180.0 );
- return r;
+ r = ( r<0.0 ? -r-180.0 : -r+180.0 );
+ } else {
+ r = 0.0;
+ }
+
+ return r;
}
+#endif
-double FGSteam::get_HackOBS1_deg ()
-{ return NAV1_Rad;
+double FGSteam::get_HackOBS1_deg () {
+ return current_radiostack->get_nav1_radial();
}
-double FGSteam::get_HackOBS2_deg ()
-{ return NAV2_Rad;
+double FGSteam::get_HackOBS2_deg () {
+ return current_radiostack->get_nav2_radial();
}
-double FGSteam::get_HackADF_deg ()
-{ double r;
- double x,y;
- y = 60.0 * ( ADF_Lat - FGBFI::getLatitude () );
- x = 60.0 * ( ADF_Lon - FGBFI::getLongitude() )
- * cos ( FGBFI::getLatitude () / RAD_TO_DEG );
- r = atan2 ( x, y ) * RAD_TO_DEG - FGBFI::getHeading ();
+double FGSteam::get_HackADF_deg () {
+ static double last_r = 0;
+
+ if ( current_radiostack->get_adf_inrange() ) {
+ double r = current_radiostack->get_adf_heading()
+ - fgGetDouble("/orientation/heading-deg");
+ last_r = r;
+ // cout << "Radial = " << current_radiostack->get_adf_heading()
+ // << " Heading = " << FGBFI::getHeading() << endl;
return r;
+ } else {
+ return last_r;
+ }
}
projects / flightgear.git / blobdiff