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 1.26 2011/12/11 17:03:05 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;
110 gAccel = GetGAccel(in.Radius);
115 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
117 double FGInertial::GetGAccel(double r) const
122 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
124 // Calculate the WGS84 gravitation value in ECEF frame. Pass in the ECEF position
125 // via the position parameter. The J2Gravity value returned is in ECEF frame,
126 // and therefore may need to be expressed (transformed) in another frame,
127 // depending on how it is used. See Stevens and Lewis eqn. 1.4-16.
129 FGColumnVector3 FGInertial::GetGravityJ2(const FGColumnVector3& position) const
131 FGColumnVector3 J2Gravity;
134 double r = position.Magnitude();
135 double sinLat = sin(in.Latitude);
138 double preCommon = 1.5*J2*adivr*adivr;
139 double xy = 1.0 - 5.0*(sinLat*sinLat);
140 double z = 3.0 - 5.0*(sinLat*sinLat);
141 double GMOverr2 = GM/(r*r);
143 J2Gravity(1) = -GMOverr2 * ((1.0 + (preCommon * xy)) * position(eX)/r);
144 J2Gravity(2) = -GMOverr2 * ((1.0 + (preCommon * xy)) * position(eY)/r);
145 J2Gravity(3) = -GMOverr2 * ((1.0 + (preCommon * z)) * position(eZ)/r);
150 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
152 void FGInertial::bind(void)
154 PropertyManager->Tie("inertial/sea-level-radius_ft", this, &FGInertial::GetRefRadius);
157 //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
158 // The bitmasked value choices are as follows:
159 // unset: In this case (the default) JSBSim would only print
160 // out the normally expected messages, essentially echoing
161 // the config files as they are read. If the environment
162 // variable is not set, debug_lvl is set to 1 internally
163 // 0: This requests JSBSim not to output any messages
165 // 1: This value explicity requests the normal JSBSim
167 // 2: This value asks for a message to be printed out when
168 // a class is instantiated
169 // 4: When this value is set, a message is displayed when a
170 // FGModel object executes its Run() method
171 // 8: When this value is set, various runtime state variables
172 // are printed out periodically
173 // 16: When set various parameters are sanity checked and
174 // a message is printed out when they go out of bounds
176 void FGInertial::Debug(int from)
178 if (debug_lvl <= 0) return;
180 if (debug_lvl & 1) { // Standard console startup message output
181 if (from == 0) { // Constructor
185 if (debug_lvl & 2 ) { // Instantiation/Destruction notification
186 if (from == 0) cout << "Instantiated: FGInertial" << endl;
187 if (from == 1) cout << "Destroyed: FGInertial" << endl;
189 if (debug_lvl & 4 ) { // Run() method entry print for FGModel-derived objects
191 if (debug_lvl & 8 ) { // Runtime state variables
193 if (debug_lvl & 16) { // Sanity checking
195 if (debug_lvl & 64) {
196 if (from == 0) { // Constructor
197 cout << IdSrc << endl;
198 cout << IdHdr << endl;