src/FDM/JSBSim/models/FGAuxiliary.cpp

   1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2
   3  Module:       FGAuxiliary.cpp
   4  Author:       Tony Peden, Jon Berndt
   5  Date started: 01/26/99
   6  Purpose:      Calculates additional parameters needed by the visual system, etc.
   7  Called by:    FGSimExec
   8
   9  ------------- Copyright (C) 1999  Jon S. Berndt (jsb@hal-pc.org) -------------
  10
  11  This program is free software; you can redistribute it and/or modify it under
  12  the terms of the GNU Lesser General Public License as published by the Free Software
  13  Foundation; either version 2 of the License, or (at your option) any later
  14  version.
  15
  16  This program is distributed in the hope that it will be useful, but WITHOUT
  17  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
  19  details.
  20
  21  You should have received a copy of the GNU Lesser General Public License along with
  22  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  23  Place - Suite 330, Boston, MA  02111-1307, USA.
  24
  25  Further information about the GNU Lesser General Public License can also be found on
  26  the world wide web at http://www.gnu.org.
  27
  28 FUNCTIONAL DESCRIPTION
  29 --------------------------------------------------------------------------------
  30 This class calculates various auxiliary parameters.
  31
  32 REFERENCES
  33   Anderson, John D. "Introduction to Flight", 3rd Edition, McGraw-Hill, 1989
  34                     pgs. 112-126
  35 HISTORY
  36 --------------------------------------------------------------------------------
  37 01/26/99   JSB   Created
  38
  39 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  40 INCLUDES
  41 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  42
  43 #include "FGAuxiliary.h"
  44 #include "FGAerodynamics.h"
  45 #include "FGPropagate.h"
  46 #include "FGAtmosphere.h"
  47 #include <FGFDMExec.h>
  48 #include "FGAircraft.h"
  49 #include "FGInertial.h"
  50 #include "FGExternalReactions.h"
  51 #include "FGBuoyantForces.h"
  52 #include "FGGroundReactions.h"
  53 #include "FGPropulsion.h"
  54 #include <input_output/FGPropertyManager.h>
  55
  56 namespace JSBSim {
  57
  58 static const char *IdSrc = "$Id$";
  59 static const char *IdHdr = ID_AUXILIARY;
  60
  61 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  62 CLASS IMPLEMENTATION
  63 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
  64
  65
  66 FGAuxiliary::FGAuxiliary(FGFDMExec* fdmex) : FGModel(fdmex)
  67 {
  68   Name = "FGAuxiliary";
  69   vcas = veas = pt = tat = 0;
  70   psl = rhosl = 1;
  71   qbar = 0;
  72   qbarUW = 0.0;
  73   qbarUV = 0.0;
  74   Re = 0.0;
  75   Mach = 0.0;
  76   alpha = beta = 0.0;
  77   adot = bdot = 0.0;
  78   gamma = Vt = Vground = 0.0;
  79   psigt = 0.0;
  80   day_of_year = 1;
  81   seconds_in_day = 0.0;
  82   hoverbmac = hoverbcg = 0.0;
  83   tatc = RankineToCelsius(tat);
  84
  85   vPilotAccel.InitMatrix();
  86   vPilotAccelN.InitMatrix();
  87   vToEyePt.InitMatrix();
  88   vAeroPQR.InitMatrix();
  89   vEulerRates.InitMatrix();
  90
  91   bind();
  92
  93   Debug(0);
  94 }
  95
  96 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  97
  98 bool FGAuxiliary::InitModel(void)
  99 {
 100   if (!FGModel::InitModel()) return false;
 101
 102   vcas = veas = pt = tat = 0;
 103   psl = rhosl = 1;
 104   qbar = 0;
 105   qbarUW = 0.0;
 106   qbarUV = 0.0;
 107   Mach = 0.0;
 108   alpha = beta = 0.0;
 109   adot = bdot = 0.0;
 110   gamma = Vt = Vground = 0.0;
 111   psigt = 0.0;
 112   day_of_year = 1;
 113   seconds_in_day = 0.0;
 114   hoverbmac = hoverbcg = 0.0;
 115
 116   vPilotAccel.InitMatrix();
 117   vPilotAccelN.InitMatrix();
 118   vToEyePt.InitMatrix();
 119   vAeroPQR.InitMatrix();
 120   vEulerRates.InitMatrix();
 121
 122   return true;
 123 }
 124
 125 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 126
 127 FGAuxiliary::~FGAuxiliary()
 128 {
 129   Debug(1);
 130 }
 131
 132 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 133
 134 bool FGAuxiliary::Run()
 135 {
 136   double A,B,D;
 137
 138   if (FGModel::Run()) return true; // return true if error returned from base class
 139   if (FDMExec->Holding()) return false;
 140
 141   const FGColumnVector3& vPQR = Propagate->GetPQR();
 142   const FGColumnVector3& vUVW = Propagate->GetUVW();
 143   const FGColumnVector3& vUVWdot = Propagate->GetUVWdot();
 144   const FGColumnVector3& vVel = Propagate->GetVel();
 145
 146   p = Atmosphere->GetPressure();
 147   rhosl = Atmosphere->GetDensitySL();
 148   psl = Atmosphere->GetPressureSL();
 149   sat = Atmosphere->GetTemperature();
 150
 151 // Rotation
 152
 153   double cTht = Propagate->GetCosEuler(eTht);
 154   double sTht = Propagate->GetSinEuler(eTht);
 155   double cPhi = Propagate->GetCosEuler(ePhi);
 156   double sPhi = Propagate->GetSinEuler(ePhi);
 157
 158   vEulerRates(eTht) = vPQR(eQ)*cPhi - vPQR(eR)*sPhi;
 159   if (cTht != 0.0) {
 160     vEulerRates(ePsi) = (vPQR(eQ)*sPhi + vPQR(eR)*cPhi)/cTht;
 161     vEulerRates(ePhi) = vPQR(eP) + vEulerRates(ePsi)*sTht;
 162   }
 163
 164 // 12/16/2005, JSB: For ground handling purposes, at this time, let's ramp
 165 // in the effects of wind from 10 fps to 30 fps when there is weight on the
 166 // landing gear wheels.
 167
 168   if (GroundReactions->GetWOW() && vUVW(eU) < 10) {
 169     vAeroPQR = vPQR;
 170     vAeroUVW = vUVW;
 171   } else if (GroundReactions->GetWOW() && vUVW(eU) < 30) {
 172     double factor = (vUVW(eU) - 10.0)/20.0;
 173     vAeroPQR = vPQR - factor*Atmosphere->GetTurbPQR();
 174     vAeroUVW = vUVW - factor*Propagate->GetTl2b()*Atmosphere->GetTotalWindNED();
 175   } else {
 176     FGColumnVector3 wind = Propagate->GetTl2b()*Atmosphere->GetTotalWindNED();
 177     vAeroPQR = vPQR - Atmosphere->GetTurbPQR();
 178     vAeroUVW = vUVW - wind;
 179   }
 180
 181   Vt = vAeroUVW.Magnitude();
 182   if ( Vt > 0.05) {
 183     if (vAeroUVW(eW) != 0.0)
 184       alpha = vAeroUVW(eU)*vAeroUVW(eU) > 0.0 ? atan2(vAeroUVW(eW), vAeroUVW(eU)) : 0.0;
 185     if (vAeroUVW(eV) != 0.0)
 186       beta = vAeroUVW(eU)*vAeroUVW(eU)+vAeroUVW(eW)*vAeroUVW(eW) > 0.0 ? atan2(vAeroUVW(eV),
 187              sqrt(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW))) : 0.0;
 188
 189     double mUW = (vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW));
 190     double signU=1;
 191     if (vAeroUVW(eU) != 0.0)
 192       signU = vAeroUVW(eU)/fabs(vAeroUVW(eU));
 193
 194     if ( (mUW == 0.0) || (Vt == 0.0) ) {
 195       adot = 0.0;
 196       bdot = 0.0;
 197     } else {
 198       adot = (vAeroUVW(eU)*vUVWdot(eW) - vAeroUVW(eW)*vUVWdot(eU))/mUW;
 199       bdot = (signU*mUW*vUVWdot(eV) - vAeroUVW(eV)*(vAeroUVW(eU)*vUVWdot(eU)
 200               + vAeroUVW(eW)*vUVWdot(eW)))/(Vt*Vt*sqrt(mUW));
 201     }
 202   } else {
 203     alpha = beta = adot = bdot = 0;
 204   }
 205
 206   Re = Vt * Aircraft->Getcbar() / Atmosphere->GetKinematicViscosity();
 207
 208   qbar = 0.5*Atmosphere->GetDensity()*Vt*Vt;
 209   qbarUW = 0.5*Atmosphere->GetDensity()*(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eW)*vAeroUVW(eW));
 210   qbarUV = 0.5*Atmosphere->GetDensity()*(vAeroUVW(eU)*vAeroUVW(eU) + vAeroUVW(eV)*vAeroUVW(eV));
 211   Mach = Vt / Atmosphere->GetSoundSpeed();
 212   MachU = vMachUVW(eU) = vAeroUVW(eU) / Atmosphere->GetSoundSpeed();
 213   vMachUVW(eV) = vAeroUVW(eV) / Atmosphere->GetSoundSpeed();
 214   vMachUVW(eW) = vAeroUVW(eW) / Atmosphere->GetSoundSpeed();
 215
 216 // Position
 217
 218   Vground = sqrt( vVel(eNorth)*vVel(eNorth) + vVel(eEast)*vVel(eEast) );
 219
 220   psigt = atan2(vVel(eEast), vVel(eNorth));
 221   if (psigt < 0.0) psigt += 2*M_PI;
 222   gamma = atan2(-vVel(eDown), Vground);
 223
 224   tat = sat*(1 + 0.2*Mach*Mach); // Total Temperature, isentropic flow
 225   tatc = RankineToCelsius(tat);
 226
 227   if (MachU < 1) {   // Calculate total pressure assuming isentropic flow
 228     pt = p*pow((1 + 0.2*MachU*MachU),3.5);
 229   } else {
 230     // Use Rayleigh pitot tube formula for normal shock in front of pitot tube
 231     B = 5.76*MachU*MachU/(5.6*MachU*MachU - 0.8);
 232     D = (2.8*MachU*MachU-0.4)*0.4167;
 233     pt = p*pow(B,3.5)*D;
 234   }
 235
 236   A = pow(((pt-p)/psl+1),0.28571);
 237   if (MachU > 0.0) {
 238     vcas = sqrt(7*psl/rhosl*(A-1));
 239     veas = sqrt(2*qbar/rhosl);
 240   } else {
 241     vcas = veas = 0.0;
 242   }
 243
 244   vPilotAccel.InitMatrix();
 245   if ( Vt > 1.0 ) {
 246      vAircraftAccel = Aerodynamics->GetForces()
 247                     + Propulsion->GetForces()
 248                     + GroundReactions->GetForces()
 249                     + ExternalReactions->GetForces()
 250                     + BuoyantForces->GetForces();
 251
 252      vAircraftAccel /= MassBalance->GetMass();
 253      // Nz is Acceleration in "g's", along normal axis (-Z body axis)
 254      Nz = -vAircraftAccel(eZ)/Inertial->gravity();
 255      vToEyePt = MassBalance->StructuralToBody(Aircraft->GetXYZep());
 256      vPilotAccel = vAircraftAccel + Propagate->GetPQRdot() * vToEyePt;
 257      vPilotAccel += vPQR * (vPQR * vToEyePt);
 258   } else {
 259      // The line below handles low velocity (and on-ground) cases, basically
 260      // representing the opposite of the force that the landing gear would
 261      // exert on the ground (which is just the total weight). This eliminates
 262      // any jitter that could be introduced by the landing gear. Theoretically,
 263      // this branch could be eliminated, with a penalty of having a short
 264      // transient at startup (lasting only a fraction of a second).
 265      vPilotAccel = Propagate->GetTl2b() * FGColumnVector3( 0.0, 0.0, -Inertial->gravity() );
 266      Nz = -vPilotAccel(eZ)/Inertial->gravity();
 267   }
 268
 269   vPilotAccelN = vPilotAccel/Inertial->gravity();
 270
 271   // VRP computation
 272   const FGLocation& vLocation = Propagate->GetLocation();
 273   FGColumnVector3 vrpStructural = Aircraft->GetXYZvrp();
 274   FGColumnVector3 vrpBody = MassBalance->StructuralToBody( vrpStructural );
 275   FGColumnVector3 vrpLocal = Propagate->GetTb2l() * vrpBody;
 276   vLocationVRP = vLocation.LocalToLocation( vrpLocal );
 277
 278   // Recompute some derived values now that we know the dependent parameters values ...
 279   hoverbcg = Propagate->GetDistanceAGL() / Aircraft->GetWingSpan();
 280
 281   FGColumnVector3 vMac = Propagate->GetTb2l()*MassBalance->StructuralToBody(Aircraft->GetXYZrp());
 282   hoverbmac = (Propagate->GetDistanceAGL() + vMac(3)) / Aircraft->GetWingSpan();
 283
 284   // when all model are executed,
 285   // please calculate the distance from the initial point
 286
 287   CalculateRelativePosition();
 288
 289   return false;
 290 }
 291
 292 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 293 //
 294 // A positive headwind is blowing with you, a negative headwind is blowing against you.
 295 // psi is the direction the wind is blowing *towards*.
 296
 297 double FGAuxiliary::GetHeadWind(void) const
 298 {
 299   double psiw,vw;
 300
 301   psiw = Atmosphere->GetWindPsi();
 302   vw = Atmosphere->GetTotalWindNED().Magnitude();
 303
 304   return vw*cos(psiw - Propagate->GetEuler(ePsi));
 305 }
 306
 307 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 308 //
 309 // A positive crosswind is blowing towards the right (from teh perspective of the
 310 // pilot). A negative crosswind is blowing towards the -Y direction (left).
 311 // psi is the direction the wind is blowing *towards*.
 312
 313 double FGAuxiliary::GetCrossWind(void) const
 314 {
 315   double psiw,vw;
 316
 317   psiw = Atmosphere->GetWindPsi();
 318   vw = Atmosphere->GetTotalWindNED().Magnitude();
 319
 320   return  vw*sin(psiw - Propagate->GetEuler(ePsi));
 321 }
 322
 323 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 324
 325 void FGAuxiliary::bind(void)
 326 {
 327   typedef double (FGAuxiliary::*PMF)(int) const;
 328   typedef double (FGAuxiliary::*PF)(void) const;
 329   PropertyManager->Tie("propulsion/tat-r", this, &FGAuxiliary::GetTotalTemperature);
 330   PropertyManager->Tie("propulsion/tat-c", this, &FGAuxiliary::GetTAT_C);
 331   PropertyManager->Tie("propulsion/pt-lbs_sqft", this, &FGAuxiliary::GetTotalPressure);
 332   PropertyManager->Tie("velocities/vc-fps", this, &FGAuxiliary::GetVcalibratedFPS);
 333   PropertyManager->Tie("velocities/vc-kts", this, &FGAuxiliary::GetVcalibratedKTS);
 334   PropertyManager->Tie("velocities/ve-fps", this, &FGAuxiliary::GetVequivalentFPS);
 335   PropertyManager->Tie("velocities/ve-kts", this, &FGAuxiliary::GetVequivalentKTS);
 336   PropertyManager->Tie("velocities/machU", this, &FGAuxiliary::GetMachU);
 337   PropertyManager->Tie("velocities/p-aero-rad_sec", this, eX, (PMF)&FGAuxiliary::GetAeroPQR);
 338   PropertyManager->Tie("velocities/q-aero-rad_sec", this, eY, (PMF)&FGAuxiliary::GetAeroPQR);
 339   PropertyManager->Tie("velocities/r-aero-rad_sec", this, eZ, (PMF)&FGAuxiliary::GetAeroPQR);
 340   PropertyManager->Tie("velocities/phidot-rad_sec", this, ePhi, (PMF)&FGAuxiliary::GetEulerRates);
 341   PropertyManager->Tie("velocities/thetadot-rad_sec", this, eTht, (PMF)&FGAuxiliary::GetEulerRates);
 342   PropertyManager->Tie("velocities/psidot-rad_sec", this, ePsi, (PMF)&FGAuxiliary::GetEulerRates);
 343   PropertyManager->Tie("velocities/u-aero-fps", this, eU, (PMF)&FGAuxiliary::GetAeroUVW);
 344   PropertyManager->Tie("velocities/v-aero-fps", this, eV, (PMF)&FGAuxiliary::GetAeroUVW);
 345   PropertyManager->Tie("velocities/w-aero-fps", this, eW, (PMF)&FGAuxiliary::GetAeroUVW);
 346   PropertyManager->Tie("velocities/vt-fps", this, &FGAuxiliary::GetVt, &FGAuxiliary::SetVt, true);
 347   PropertyManager->Tie("velocities/mach", this, &FGAuxiliary::GetMach, &FGAuxiliary::SetMach, true);
 348   PropertyManager->Tie("velocities/vg-fps", this, &FGAuxiliary::GetVground);
 349   PropertyManager->Tie("accelerations/a-pilot-x-ft_sec2", this, eX, (PMF)&FGAuxiliary::GetPilotAccel);
 350   PropertyManager->Tie("accelerations/a-pilot-y-ft_sec2", this, eY, (PMF)&FGAuxiliary::GetPilotAccel);
 351   PropertyManager->Tie("accelerations/a-pilot-z-ft_sec2", this, eZ, (PMF)&FGAuxiliary::GetPilotAccel);
 352   PropertyManager->Tie("accelerations/n-pilot-x-norm", this, eX, (PMF)&FGAuxiliary::GetNpilot);
 353   PropertyManager->Tie("accelerations/n-pilot-y-norm", this, eY, (PMF)&FGAuxiliary::GetNpilot);
 354   PropertyManager->Tie("accelerations/n-pilot-z-norm", this, eZ, (PMF)&FGAuxiliary::GetNpilot);
 355   PropertyManager->Tie("accelerations/Nz", this, &FGAuxiliary::GetNz);
 356   /* PropertyManager->Tie("atmosphere/headwind-fps", this, &FGAuxiliary::GetHeadWind, true);
 357   PropertyManager->Tie("atmosphere/crosswind-fps", this, &FGAuxiliary::GetCrossWind, true); */
 358   PropertyManager->Tie("aero/alpha-rad", this, (PF)&FGAuxiliary::Getalpha, &FGAuxiliary::Setalpha, true);
 359   PropertyManager->Tie("aero/beta-rad", this, (PF)&FGAuxiliary::Getbeta, &FGAuxiliary::Setbeta, true);
 360   PropertyManager->Tie("aero/mag-beta-rad", this, (PF)&FGAuxiliary::GetMagBeta);
 361   PropertyManager->Tie("aero/alpha-deg", this, inDegrees, (PMF)&FGAuxiliary::Getalpha);
 362   PropertyManager->Tie("aero/beta-deg", this, inDegrees, (PMF)&FGAuxiliary::Getbeta);
 363   PropertyManager->Tie("aero/mag-beta-deg", this, inDegrees, (PMF)&FGAuxiliary::GetMagBeta);
 364   PropertyManager->Tie("aero/Re", this, &FGAuxiliary::GetReynoldsNumber);
 365   PropertyManager->Tie("aero/qbar-psf", this, &FGAuxiliary::Getqbar, &FGAuxiliary::Setqbar, true);
 366   PropertyManager->Tie("aero/qbarUW-psf", this, &FGAuxiliary::GetqbarUW, &FGAuxiliary::SetqbarUW, true);
 367   PropertyManager->Tie("aero/qbarUV-psf", this, &FGAuxiliary::GetqbarUV, &FGAuxiliary::SetqbarUV, true);
 368   PropertyManager->Tie("aero/alphadot-rad_sec", this, (PF)&FGAuxiliary::Getadot, &FGAuxiliary::Setadot, true);
 369   PropertyManager->Tie("aero/betadot-rad_sec", this, (PF)&FGAuxiliary::Getbdot, &FGAuxiliary::Setbdot, true);
 370   PropertyManager->Tie("aero/alphadot-deg_sec", this, inDegrees, (PMF)&FGAuxiliary::Getadot);
 371   PropertyManager->Tie("aero/betadot-deg_sec", this, inDegrees, (PMF)&FGAuxiliary::Getbdot);
 372   PropertyManager->Tie("aero/h_b-cg-ft", this, &FGAuxiliary::GetHOverBCG);
 373   PropertyManager->Tie("aero/h_b-mac-ft", this, &FGAuxiliary::GetHOverBMAC);
 374   PropertyManager->Tie("flight-path/gamma-rad", this, &FGAuxiliary::GetGamma, &FGAuxiliary::SetGamma);
 375   PropertyManager->Tie("flight-path/psi-gt-rad", this, &FGAuxiliary::GetGroundTrack);
 376
 377   PropertyManager->Tie("position/distance-from-start-lon-mt", this, &FGAuxiliary::GetLongitudeRelativePosition);
 378   PropertyManager->Tie("position/distance-from-start-lat-mt", this, &FGAuxiliary::GetLatitudeRelativePosition);
 379   PropertyManager->Tie("position/distance-from-start-mag-mt", this, &FGAuxiliary::GetDistanceRelativePosition);
 380 }
 381
 382 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 383
 384 void FGAuxiliary::CalculateRelativePosition(void)
 385 {
 386   const double earth_radius_mt = Inertial->GetRefRadius()*fttom;
 387   lat_relative_position=(FDMExec->GetPropagate()->GetLatitude()  - FDMExec->GetIC()->GetLatitudeDegIC() *degtorad)*earth_radius_mt;
 388   lon_relative_position=(FDMExec->GetPropagate()->GetLongitude() - FDMExec->GetIC()->GetLongitudeDegIC()*degtorad)*earth_radius_mt;
 389   relative_position = sqrt(lat_relative_position*lat_relative_position + lon_relative_position*lon_relative_position);
 390 };
 391
 392 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 393 //    The bitmasked value choices are as follows:
 394 //    unset: In this case (the default) JSBSim would only print
 395 //       out the normally expected messages, essentially echoing
 396 //       the config files as they are read. If the environment
 397 //       variable is not set, debug_lvl is set to 1 internally
 398 //    0: This requests JSBSim not to output any messages
 399 //       whatsoever.
 400 //    1: This value explicity requests the normal JSBSim
 401 //       startup messages
 402 //    2: This value asks for a message to be printed out when
 403 //       a class is instantiated
 404 //    4: When this value is set, a message is displayed when a
 405 //       FGModel object executes its Run() method
 406 //    8: When this value is set, various runtime state variables
 407 //       are printed out periodically
 408 //    16: When set various parameters are sanity checked and
 409 //       a message is printed out when they go out of bounds
 410
 411 void FGAuxiliary::Debug(int from)
 412 {
 413   if (debug_lvl <= 0) return;
 414
 415   if (debug_lvl & 1) { // Standard console startup message output
 416     if (from == 0) { // Constructor
 417
 418     }
 419   }
 420   if (debug_lvl & 2 ) { // Instantiation/Destruction notification
 421     if (from == 0) cout << "Instantiated: FGAuxiliary" << endl;
 422     if (from == 1) cout << "Destroyed:    FGAuxiliary" << endl;
 423   }
 424   if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
 425   }
 426   if (debug_lvl & 8 ) { // Runtime state variables
 427   }
 428   if (debug_lvl & 16) { // Sanity checking
 429     if (Mach > 100 || Mach < 0.00)
 430       cout << "FGPropagate::Mach is out of bounds: " << Mach << endl;
 431     if (qbar > 1e6 || qbar < 0.00)
 432       cout << "FGPropagate::qbar is out of bounds: " << qbar << endl;
 433   }
 434   if (debug_lvl & 64) {
 435     if (from == 0) { // Constructor
 436       cout << IdSrc << endl;
 437       cout << IdHdr << endl;
 438     }
 439   }
 440 }
 441
 442 } // namespace JSBSim