
/**
 * @file MOPSWeight.hpp
 * Class to assign weights to satellites based on the Appendix J of MOPS C.
 */

#ifndef MOPSWEIGHT_BASE_GPSTK
#define MOPSWEIGHT_BASE_GPSTK

//============================================================================
//
//  This file is part of GPSTk, the GPS Toolkit.
//
//  The GPSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 2.1 of the License, or
//  any later version.
//
//  The GPSTk 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 Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GPSTk; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//  
//  Dagoberto Salazar - gAGE. 2006
//
//============================================================================



#include "WeightBase.hpp"
#include "EphemerisStore.hpp"
#include "BCEphemerisStore.hpp"
#include "TabularEphemerisStore.hpp"
#include "EngEphemeris.hpp"
#include "RinexObsHeader.hpp"
#include "Position.hpp"
#include "SimpleIURAWeight.hpp"
#include "TropModel.hpp"
#include "icd_200_constants.hpp"
#include "geometry.hpp"                   // DEG_TO_RAD
#include <cmath>
#include <vector>


namespace gpstk
{

    /** @addtogroup GPSsolutions */
    //@{

    /** Class to assign weights to satellites based on the Appendix J of MOPS C.
     *
     * This class implements an algorithm to assign weights to satellites based on
     * the RTCA "Minimum Operational Performance Standards" (MOPS), version C 
     * (RTCA/DO-229C), sections J.2.3. "Variance of Ionospheric Delay", J.2.4. 
     * "Variance of Airborne Receiver Errors" and J.2.5. "Variance of Tropospheric 
     * errors".
     *
     * It is meant to be used with the class "MOPSTropModel".
     * 
     */
    class MOPSWeight: WeightBase
    {
    public:

        /// Empty constructor
        MOPSWeight(void) { valid = false; };


        /** Compute and return a vector with the weights for the given satellites
         * @param time               Epoch weights will be computed for
         * @param Satellites         Vector of satellites
         * @param bcEph              Satellite broadcast ephemeris
         * @param ionoCorrections    Ionospheric corrections computed using Klobuchar model
         * @param elevationVector    Vector of elevations, in degrees
         * @param azimuthVector      Vector of azimuths, in degrees
         * @param rxPosition         Position of the receiver
         * @param rxClass            Integer indicating receiver class according MOPS-C.
         *                           It is 2 by default (conservative setting).
         * 
         * @return
         *  Number of satellites with valid weights
         *
         * \note
         * Method isValid() will return false if some satellite does not have a
         * valid weight. Also, its PRN will be set to a negative value.
         *
         */
        virtual int getWeights(DayTime& time, Vector<SatID>& Satellites, BCEphemerisStore& bcEph, Vector<double>& ionoCorrections, Vector<double>& elevationVector, Vector<double>& azimuthVector, Position rxPosition, int rxClass=2) throw(InvalidWeights);


        /** Compute and return a vector with the weights for the given satellites
         * @param time               Epoch weights will be computed for
         * @param Satellites         Vector of satellites
         * @param preciseEph         Satellite precise ephemeris
         * @param ionoCorrections    Ionospheric corrections computed using Klobuchar model
         * @param elevationVector    Vector of elevations, in degrees
         * @param azimuthVector      Vector of azimuths, in degrees
         * @param rxPosition         Position of the receiver
         * @param rxClass            Integer indicating receiver class according MOPS-C.
         *                           It is 2 by default (conservative setting).
         * 
         * @return
         *  Number of satellites with valid weights
         *
         * \note
         * Method isValid() will return false if some satellite does not have a
         * valid weight. Also, its PRN will be set to a negative value.
         *
         */
        virtual int getWeights(DayTime& time, Vector<SatID>& Satellites, TabularEphemerisStore& preciseEph, Vector<double>& ionoCorrections, Vector<double>& elevationVector, Vector<double>& azimuthVector, Position rxPosition, int rxClass=2) throw(InvalidWeights);


        /// Vector of weights for these satellites
        Vector<double> weightsVector;

        /// Vector with the PRN of satellites with weights available for computing.
        Vector<SatID> availableSV;

        /// Vector with the PRN of satellites rejected or with no proper weights.
        Vector<SatID> rejectedSV;

        /// Return validity of weights
        virtual bool isValid(void)
            { return valid; }


    private:

        /// Compute satellites' weights
        void Compute(int goodSV, SimpleIURAWeight& sIura, Vector<SatID>& Satellites, Vector<double>& ionoCorrections, Vector<double>& elevationVector, Vector<double>& azimuthVector, Position rxPosition, int rxClass) throw(InvalidWeights);


        /// Compute ionospheric sigma^2 according to Appendix J.2.3 and Appendix A.4.4.10.4 in MOPS-C
        double sigma2iono(double& ionoCorrection, double& elevation, double& azimuth, Position rxPosition) throw(InvalidWeights);

   }; // end class MOPSWeight
   

   //@}
   
}

#endif
