1 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6 Purpose: Encapsulates the inertial frame forces (coriolis and centrifugal)
8 ------------- Copyright (C) 2000 Jon S. Berndt (jon@jsbsim.org) -------------
10 This program is free software; you can redistribute it and/or modify it under
11 the terms of the GNU Lesser General Public License as published by the Free Software
12 Foundation; either version 2 of the License, or (at your option) any later
15 This program is distributed in the hope that it will be useful, but WITHOUT
16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
20 You should have received a copy of the GNU Lesser General Public License along with
21 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
22 Place - Suite 330, Boston, MA 02111-1307, USA.
24 Further information about the GNU Lesser General Public License can also be found on
25 the world wide web at http://www.gnu.org.
27 FUNCTIONAL DESCRIPTION
28 --------------------------------------------------------------------------------
31 --------------------------------------------------------------------------------
34 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
36 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
38 #include "FGInertial.h"
39 #include "FGFDMExec.h"
46 static const char *IdSrc = "$Id: FGInertial.cpp,v 1.25 2011/10/31 14:54:41 bcoconni Exp $";
47 static const char *IdHdr = ID_INERTIAL;
49 /*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
51 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
54 FGInertial::FGInertial(FGFDMExec* fgex) : FGModel(fgex)
59 RotationRate = 0.00007292115;
60 GM = 14.07644180E15; // WGS84 value
61 RadiusReference = 20925650.00; // Equatorial radius (WGS84)
62 C2_0 = -4.84165371736E-04; // WGS84 value for the C2,0 coefficient
63 J2 = 1.0826266836E-03; // WGS84 value for J2
64 a = 20925646.3255; // WGS84 semimajor axis length in feet
65 b = 20855486.5951; // WGS84 semiminor axis length in feet
69 RotationRate = 0.0000026617;
70 GM = 1.7314079E14; // Lunar GM
71 RadiusReference = 5702559.05; // Equatorial radius
72 C2_0 = 0; // value for the C2,0 coefficient
73 J2 = 2.033542482111609E-4; // value for J2
74 a = 5702559.05; // semimajor axis length in feet
75 b = 5695439.63; // semiminor axis length in feet
78 vOmegaPlanet = FGColumnVector3( 0.0, 0.0, RotationRate );
79 gAccelReference = GM/(RadiusReference*RadiusReference);
80 gAccel = GM/(RadiusReference*RadiusReference);
87 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
89 FGInertial::~FGInertial(void)
94 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
96 bool FGInertial::InitModel(void)
101 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
103 bool FGInertial::Run(bool Holding)
105 // Fast return if we have nothing to do ...
106 if (FGModel::Run(Holding)) return true;
107 if (Holding) return false;
112 gAccel = GetGAccel(in.Radius);
119 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
121 double FGInertial::GetGAccel(double r) const
126 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
128 // Calculate the WGS84 gravitation value in ECEF frame. Pass in the ECEF position
129 // via the position parameter. The J2Gravity value returned is in ECEF frame,
130 // and therefore may need to be expressed (transformed) in another frame,
131 // depending on how it is used. See Stevens and Lewis eqn. 1.4-16.
133 FGColumnVector3 FGInertial::GetGravityJ2(const FGColumnVector3& position) const
135 FGColumnVector3 J2Gravity;
138 double r = position.Magnitude();
139 double sinLat = sin(in.Latitude);
142 double preCommon = 1.5*J2*adivr*adivr;
143 double xy = 1.0 - 5.0*(sinLat*sinLat);
144 double z = 3.0 - 5.0*(sinLat*sinLat);
145 double GMOverr2 = GM/(r*r);
147 J2Gravity(1) = -GMOverr2 * ((1.0 + (preCommon * xy)) * position(eX)/r);
148 J2Gravity(2) = -GMOverr2 * ((1.0 + (preCommon * xy)) * position(eY)/r);
149 J2Gravity(3) = -GMOverr2 * ((1.0 + (preCommon * z)) * position(eZ)/r);
154 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
156 void FGInertial::bind(void)
158 PropertyManager->Tie("inertial/sea-level-radius_ft", this, &FGInertial::GetRefRadius);
161 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
162 // The bitmasked value choices are as follows:
163 // unset: In this case (the default) JSBSim would only print
164 // out the normally expected messages, essentially echoing
165 // the config files as they are read. If the environment
166 // variable is not set, debug_lvl is set to 1 internally
167 // 0: This requests JSBSim not to output any messages
169 // 1: This value explicity requests the normal JSBSim
171 // 2: This value asks for a message to be printed out when
172 // a class is instantiated
173 // 4: When this value is set, a message is displayed when a
174 // FGModel object executes its Run() method
175 // 8: When this value is set, various runtime state variables
176 // are printed out periodically
177 // 16: When set various parameters are sanity checked and
178 // a message is printed out when they go out of bounds
180 void FGInertial::Debug(int from)
182 if (debug_lvl <= 0) return;
184 if (debug_lvl & 1) { // Standard console startup message output
185 if (from == 0) { // Constructor
189 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
190 if (from == 0) cout << "Instantiated: FGInertial" << endl;
191 if (from == 1) cout << "Destroyed: FGInertial" << endl;
193 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
195 if (debug_lvl & 8 ) { // Runtime state variables
197 if (debug_lvl & 16) { // Sanity checking
199 if (debug_lvl & 64) {
200 if (from == 0) { // Constructor
201 cout << IdSrc << endl;
202 cout << IdHdr << endl;