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flightgear/src/FDM/JSBSim/FGPosition.cpp
tony d2156b5649 Updates. Includes property tree additions and fixes. Also Jon's first cut at 
multi-fdm capability.  Thanks also to Erik for pointing out a couple of typos.
2002-03-23 00:29:21 +00:00

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/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Module: FGPosition.cpp
Author: Jon S. Berndt
Date started: 01/05/99
Purpose: Integrate the EOM to determine instantaneous position
Called by: FGFDMExec
------------- Copyright (C) 1999 Jon S. Berndt (jsb@hal-pc.org) -------------
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
This class encapsulates the integration of rates and accelerations to get the
current position of the aircraft.
HISTORY
--------------------------------------------------------------------------------
01/05/99 JSB Created
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
COMMENTS, REFERENCES, and NOTES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[1] Cooke, Zyda, Pratt, and McGhee, "NPSNET: Flight Simulation Dynamic Modeling
Using Quaternions", Presence, Vol. 1, No. 4, pp. 404-420 Naval Postgraduate
School, January 1994
[2] D. M. Henderson, "Euler Angles, Quaternions, and Transformation Matrices",
JSC 12960, July 1977
[3] Richard E. McFarland, "A Standard Kinematic Model for Flight Simulation at
NASA-Ames", NASA CR-2497, January 1975
[4] Barnes W. McCormick, "Aerodynamics, Aeronautics, and Flight Mechanics",
Wiley & Sons, 1979 ISBN 0-471-03032-5
[5] Bernard Etkin, "Dynamics of Flight, Stability and Control", Wiley & Sons,
1982 ISBN 0-471-08936-2
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#ifdef FGFS
# include <simgear/compiler.h>
# ifdef SG_HAVE_STD_INCLUDES
# include <cmath>
# include <iomanip>
# else
# include <math.h>
# include <iomanip.h>
# endif
#else
# if defined(sgi) && !defined(__GNUC__)
# include <math.h>
# include <iomanip.h>
# else
# include <cmath>
# include <iomanip>
# endif
#endif
#include "FGPosition.h"
#include "FGAtmosphere.h"
#include "FGState.h"
#include "FGFDMExec.h"
#include "FGFCS.h"
#include "FGAircraft.h"
#include "FGMassBalance.h"
#include "FGTranslation.h"
#include "FGRotation.h"
#include "FGAuxiliary.h"
#include "FGOutput.h"
#include "FGPropertyManager.h"
static const char *IdSrc = "$Id$";
static const char *IdHdr = ID_POSITION;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS IMPLEMENTATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
extern double globalTriNormal[3];
extern double globalSceneryAltitude;
extern double globalSeaLevelRadius;
FGPosition::FGPosition(FGFDMExec* fdmex) : FGModel(fdmex)
{
Name = "FGPosition";
LongitudeDot = LatitudeDot = RadiusDot = 0.0;
lastLongitudeDot = lastLatitudeDot = lastRadiusDot = 0.0;
Longitude = Latitude = 0.0;
gamma = Vt = Vground = 0.0;
hoverbmac = hoverbcg = 0.0;
psigt = 0.0;
bind();
Debug(0);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
FGPosition::~FGPosition(void)
{
unbind();
Debug(1);
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
bool FGPosition::InitModel(void)
{
FGModel::InitModel();
h = 3.0; // Est. height of aircraft cg off runway
SeaLevelRadius = Inertial->RefRadius(); // For initialization ONLY
Radius = SeaLevelRadius + h;
RunwayRadius = SeaLevelRadius;
DistanceAGL = Radius - RunwayRadius; // Geocentric
vRunwayNormal(3) = -1.0; // Initialized for standalone mode
b = 1;
return true;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
/*
Purpose: Called on a schedule to perform Positioning algorithms
Notes: [TP] Make sure that -Vt <= hdot <= Vt, which, of course, should always
be the case
[JB] Run in standalone mode, SeaLevelRadius will be reference radius.
In FGFS, SeaLevelRadius is stuffed from FGJSBSim in JSBSim.cxx each pass.
*/
bool FGPosition::Run(void) {
double cosLat;
double hdot_Vt;
FGColumnVector3 vMac;
if (!FGModel::Run()) {
GetState();
Vground = sqrt( vVel(eNorth)*vVel(eNorth) + vVel(eEast)*vVel(eEast) );
psigt = atan2(vVel(eEast), vVel(eNorth));
if (psigt < 0.0)
psigt += 2*M_PI;
Radius = h + SeaLevelRadius;
cosLat = cos(Latitude);
if (cosLat != 0) LongitudeDot = vVel(eEast) / (Radius * cosLat);
LatitudeDot = vVel(eNorth) / Radius;
RadiusDot = -vVel(eDown);
Longitude += 0.5*dt*rate*(LongitudeDot + lastLongitudeDot);
Latitude += 0.5*dt*rate*(LatitudeDot + lastLatitudeDot);
Radius += 0.5*dt*rate*(RadiusDot + lastRadiusDot);
h = Radius - SeaLevelRadius; // Geocentric
DistanceAGL = Radius - RunwayRadius; // Geocentric
hoverbcg = DistanceAGL/b;
vMac=State->GetTb2l()*Aircraft->GetXYZrp();
vMac *= inchtoft;
hoverbmac = (DistanceAGL + vMac(3))/b;
if (Vt > 0) {
hdot_Vt = RadiusDot/Vt;
if (fabs(hdot_Vt) <= 1) gamma = asin(hdot_Vt);
} else {
gamma = 0.0;
}
lastLatitudeDot = LatitudeDot;
lastLongitudeDot = LongitudeDot;
lastRadiusDot = RadiusDot;
return false;
} else {
return true;
}
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGPosition::GetState(void) {
dt = State->Getdt();
Vt = Translation->GetVt();
vVel = State->GetTb2l() * Translation->GetUVW();
vVelDot = State->GetTb2l() * Translation->GetUVWdot();
b = Aircraft->GetWingSpan();
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGPosition::Seth(double tt) {
h = tt;
Radius = h + SeaLevelRadius;
DistanceAGL = Radius - RunwayRadius; // Geocentric
hoverbcg = DistanceAGL/b;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void FGPosition::SetDistanceAGL(double tt) {
DistanceAGL=tt;
Radius = RunwayRadius + DistanceAGL;
h = Radius - SeaLevelRadius;
hoverbcg = DistanceAGL/b;
}
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// The bitmasked value choices are as follows:
// unset: In this case (the default) JSBSim would only print
// out the normally expected messages, essentially echoing
// the config files as they are read. If the environment
// variable is not set, debug_lvl is set to 1 internally
// 0: This requests JSBSim not to output any messages
// whatsoever.
// 1: This value explicity requests the normal JSBSim
// startup messages
// 2: This value asks for a message to be printed out when
// a class is instantiated
// 4: When this value is set, a message is displayed when a
// FGModel object executes its Run() method
// 8: When this value is set, various runtime state variables
// are printed out periodically
// 16: When set various parameters are sanity checked and
// a message is printed out when they go out of bounds
void FGPosition::Debug(int from)
{
if (debug_lvl <= 0) return;
if (debug_lvl & 1) { // Standard console startup message output
if (from == 0) { // Constructor
}
}
if (debug_lvl & 2 ) { // Instantiation/Destruction notification
if (from == 0) cout << "Instantiated: FGPosition" << endl;
if (from == 1) cout << "Destroyed: FGPosition" << endl;
}
if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
}
if (debug_lvl & 8 ) { // Runtime state variables
}
if (debug_lvl & 16) { // Sanity checking
}
if (debug_lvl & 64) {
if (from == 0) { // Constructor
cout << IdSrc << endl;
cout << IdHdr << endl;
}
}
}
void FGPosition::bind(void){
PropertyManager->Tie("velocities/v-north-fps", this,
&FGPosition::GetVn);
PropertyManager->Tie("velocities/v-east-fps", this,
&FGPosition::GetVe);
PropertyManager->Tie("velocities/v-down-fps", this,
&FGPosition::GetVd);
PropertyManager->Tie("velocities/vg-fps", this,
&FGPosition::GetVground);
PropertyManager->Tie("flight-path/psi-gt-rad", this,
&FGPosition::GetGroundTrack);
PropertyManager->Tie("position/h-sl-ft", this,
&FGPosition::Geth,
&FGPosition::Seth,
true);
PropertyManager->Tie("velocities/h-dot-fps", this,
&FGPosition::Gethdot);
PropertyManager->Tie("position/lat-gc-rad", this,
&FGPosition::GetLatitude,
&FGPosition::SetLatitude);
PropertyManager->Tie("position/lat-dot-gc-rad", this,
&FGPosition::GetLatitudeDot);
PropertyManager->Tie("position/long-gc-rad", this,
&FGPosition::GetLongitude,
&FGPosition::SetLongitude,
true);
PropertyManager->Tie("position/long-dot-gc-rad", this,
&FGPosition::GetLongitudeDot);
PropertyManager->Tie("metrics/runway-radius", this,
&FGPosition::GetRunwayRadius,
&FGPosition::SetRunwayRadius);
PropertyManager->Tie("position/h-agl-ft", this,
&FGPosition::GetDistanceAGL,
&FGPosition::SetDistanceAGL);
PropertyManager->Tie("position/radius-to-vehicle-ft", this,
&FGPosition::GetRadius);
PropertyManager->Tie("flight-path/gamma-rad", this,
&FGPosition::GetGamma,
&FGPosition::SetGamma);
PropertyManager->Tie("aero/h_b-cg-ft", this,
&FGPosition::GetHOverBCG);
PropertyManager->Tie("aero/h_b-mac-ft", this,
&FGPosition::GetHOverBMAC);
}
void FGPosition::unbind(void){
PropertyManager->Untie("velocities/v-north-fps");
PropertyManager->Untie("velocities/v-east-fps");
PropertyManager->Untie("velocities/v-down-fps");
PropertyManager->Untie("velocities/vg-fps");
PropertyManager->Untie("flight-path/psi-gt-rad");
PropertyManager->Untie("position/h-sl-ft");
PropertyManager->Untie("velocities/h-dot-fps");
PropertyManager->Untie("position/lat-gc-rad");
PropertyManager->Untie("position/lat-dot-gc-rad");
PropertyManager->Untie("position/long-gc-rad");
PropertyManager->Untie("position/long-dot-gc-rad");
PropertyManager->Untie("metrics/runway-radius");
PropertyManager->Untie("position/h-agl-ft");
PropertyManager->Untie("position/radius-to-vehicle-ft");
PropertyManager->Untie("flight-path/gamma-rad");
PropertyManager->Untie("aero/h_b-cg-ft");
PropertyManager->Untie("aero/h_b-mac-ft");
}
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