SphericalHarmonicsGravityModel.h

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/*
Solar Radiation Pressure model header file
 
Author: Sam Matez
*/
/*
Metadata for MS GUI:
imdata = {"displayname" : "Spherical Harmonic Gravity",
          "exclude" : False,
          "category" : "Dynamics"
}
aliases = {"mu" : "GM",
           "filename" : "Gravity File",
           "r_planet" : "Planet Equatorial Radius",
           "body_mass" : "Spacecraft Mass",
           "n" : "Degree",
           "m" : "Order",
           "pos_body_planet__pcpf" : "Position",
           "grav_force__f" : "Gravity Force"
}
*/
 
#ifndef MODELS_SPHERICAL_HARMONICS_GRAVITY_MODEL_H 
#define MODELS_SPHERICAL_HARMONICS_GRAVITY_MODEL_H
 
#include <string>
 
#include "simulation/Model.h"
#include "utils/sphericalharmonicsutils.h"
#include "locations.h"
#include "constants/planetdefaults.h"
 
namespace warptwin {
     
    MODEL(SphericalHarmonicsGravityModel)
    public:
        // Model params
        //         NAME                     TYPE                    DEFAULT VALUE
        START_PARAMS
            SIGNAL(filename,                std::string,            warptwinDir() + "data/WGS84/WGS84.txt")
            SIGNAL(mu,                      double,                 warpos::earth_wgs84.mu)
            SIGNAL(r_planet,                double,                 warpos::earth_wgs84.eq_radius) 
            SIGNAL(n,                       int,                    0)
            SIGNAL(m,                       int,                    0)
            SIGNAL(body_mass,               double,                 1.0)
        END_PARAMS
 
        // Model inputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_INPUTS
            SIGNAL(pos_body_planet__pcpf,   CartesianVector3,      CartesianVector3({0.0, 0.0, 0.0}))
        END_INPUTS
 
        // Model Outputs
        //         NAME                     TYPE                    DEFAULT VALUE
        START_OUTPUTS
            SIGNAL(grav_accel__f,           CartesianVector3,      CartesianVector3({0.0, 0.0, 0.0}))
            SIGNAL(grav_force__f,           CartesianVector3,      CartesianVector3({0.0, 0.0, 0.0}))
        END_OUTPUTS
 
    protected:
        int16 start() override;
        int16 execute() override; 
 
        // Pre-calculated parameters
        double _K;
 
        // Variables to hold gravity coefficients
        double _c[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1];
        double _s[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1];
 
        // Local variable to hold force in the spherical frame
        CartesianVector3 _accel_grav__spherical;
 
        // Local variables for lla coordinates
        double _lat;
        double _lon;
        double _alt;
 
        // Local variable for magnitude of position vector
        double _r_pos;
 
        // Local variable to hold colatitude
        double _colatitude;
 
        // Local variables for rotation back to pcpf
        double _sth;
        double _cth;
        double _sph;
        double _cph;
        CartesianVector3 _fe;
 
    };
 
}
 
#endif