engephemeris.hpp

一个gps小工具包

#pragma ident "$Id: EngEphemeris.hpp 876 2007-11-06 14:16:30Z renfroba $"



/**
 * @file EngEphemeris.hpp
 * Ephemeris data encapsulated in engineering terms
 */

#ifndef GPSTK_ENGEPHEMERIS_HPP
#define GPSTK_ENGEPHEMERIS_HPP

//============================================================================
//
//  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
//  
//  Copyright 2004, The University of Texas at Austin
//
//============================================================================

//============================================================================
//
//This software developed by Applied Research Laboratories at the University of
//Texas at Austin, under contract to an agency or agencies within the U.S. 
//Department of Defense. The U.S. Government retains all rights to use,
//duplicate, distribute, disclose, or release this software. 
//
//Pursuant to DoD Directive 523024 
//
// DISTRIBUTION STATEMENT A: This software has been approved for public 
//                           release, distribution is unlimited.
//
//=============================================================================






#include "EngNav.hpp"
#include "Exception.hpp"
#include "DayTime.hpp"
#include "Xvt.hpp"

namespace gpstk
{
   /** @addtogroup ephemcalc */
   //@{

      /**
       * Ephemeris information for a single satellite.  This class
       * encapsulates the ephemeris navigation message (subframes 1-3)
       * and provides functions to decode the as-broadcast
       * ephemerides.
       */
   class EngEphemeris : public EngNav
   {
   public:
         /// Default constructor
      EngEphemeris() throw();

         /// Destructor
      virtual ~EngEphemeris() {}

         /**
          * Store a subframe in this object.
          * @param subframe ten word navigation subframe stored in the
          * 30 least-significant bits of each array index.
          * @param gpsWeek full GPS week number.
          * @param PRN PRN ID of source satellite.
          * @param track tracking number (typically receiver channel number).
          * @return true if successful.
          * @throw InvalidParameter if subframe is valid but not subframe 1-3.
          */
      bool addSubframe(const long subframe[10], const int gpsWeek,
                       short PRN, short track)
         throw(gpstk::InvalidParameter);
       
         /**
          * Store a subframe in this object.  This method is provided in 
          * order to allow construction of an EngEphemeris object for
          * cases where a receiver only provides the 24 msb of each
          * word and strips the parity.l  
          * @param subframe ten word navigation subframe (minus the six
          * parity bits) stored in the 24 least-significant bits of
          * each array index.
          * @param gpsWeek full GPS week number.
          * @param PRN PRN ID of source satellite.
          * @param track tracking number (typically receiver channel number).
          * @return true if successful.
          * @throw InvalidParameter if subframe is valid but not subframe 1-3.
          */
      bool addSubframeNoParity(const long subframe[10],
                               const long gpsWeek,
                               const short PRN,
                               const short track)
         throw(gpstk::InvalidParameter);

         /**
          * Store a subframe in this object.  This method is provided in
          * order to provide a path to a EngEphemeris object for cases 
          * where a receiver only provides words 3-10 of subframes 1-3.  
          * @note: It is important to appropriately determine the transmit
          * time of the data.  The parameters sf1TransmitSOW and gpsWeek
          * should be consistent and should represent the time when the
          * data in sf1, sf2, and sf3 were received.  As a general rule, 
          * the transmit time should be somewhere in the range of 0-2 hours
          * BEFORE the epoch time of the ephemeris.  
          * @note: EngEphemeris objects built via this method will not
          * contain valid TLM message data, A-S flags, and "Alert" bits.
          * Methods getTLMMesage() and getASAlert() should not be used.
          * @param sf1 words 3-10 of navigation subframe1 stored in the
          * 30 least-significant bits of each array index.
          * @param sf2 words 3-10 of navigation subframe 2
          * @param sf3 words 3-10 of navigation subframe 3
          * @param sf1TransmitSOW time (in GPS seconds of week) corresponding
          * to leading edge of first bit of subframe 1 
          * @param gpsWeek full GPS week number.
          * @param PRN PRN ID of source satellite.
          * @param track tracker number (typically receiver channel number).
          * @return true if successful.
          */
      bool addIncompleteSF1Thru3(
         const long sf1[8], const long sf2[8], const long sf3[8], 
         const long sf1TransmitSOW, const int gpsWeek,
         const short PRN, const short track);

         /**
          * Query presence of subframe in this object.
          * @param subframe subframe ID (1-3) to check.
          * @return true if the given subframe is present in this object.
          * @throw InvalidParameter if subframe is not a valid
          *   ephemeris subframe number.
          */
      bool isData(short subframe) const throw(gpstk::InvalidRequest);

         /**
          * Set the value of the SV accuracy (in meters).  This is the only
          * "set" method and is provided so that one can set the SV
          * accuracy directly and thereby override the conversion of the
          * SV accuracy flag to meters.  This is usually used when entering
          * data from some source other than an SV nav message.  
          * @note Subsequent use of the addSubframe(), with subframe 1 info,
          * or the setSF1() methods will overwrite any value set using this 
          * method.
          * @note This function converts the given accuracy to the appropriate
          * SV accuracy flag and stores it in the accFlag data member.
          * @param acc the new value of SV accuracy in meters.
          * @throw InvalidParameter if the given accuracy value is invalid.
          */
      void setAccuracy(const double& acc) throw(gpstk::InvalidParameter);
      
         /**
          * This computes and returns the fit interval for the
          * satellite ephemeris from the IODC and the fit interval
          * flag.  This fit interval is centered around the Toe (time
          * of ephemeris) for the ephemeris.  See Table 20-XIA in the
          * ICD-GPS-200 and section 20.3.3.4.3.1 for more information.
          * @return the fit interval in hours (0 = failure).
          * @throw InvalidRequest if data is missing.
          */
      short getFitInterval() const throw(gpstk::InvalidRequest);

         /// Return 0x8b, the upper 5 bits of the 22-bit TLM word.
         // kinda pointless, huh?
      unsigned char getTLMPreamble() const throw() { return 0x8b; }

         /// Return the lower 16 bits of the TLM word for the given subframe.
      unsigned getTLMMessage(short subframe) const 
         throw(gpstk::InvalidRequest);
            
         /// Extracts the epoch time from this ephemeris, correcting
         /// for half weeks and HOW time
      DayTime getEphemerisEpoch() const throw(InvalidRequest);

         /// Extracts the epoch time (time of clock) from this ephemeris, correcting
         /// for half weeks and HOW time
      DayTime getEpochTime() const throw(gpstk::InvalidRequest);

         /// Extracts the transmit time from the ephemeris using the Tot
      DayTime getTransmitTime() const throw(gpstk::InvalidRequest);
      
         /// used for template functions
      DayTime getTimestamp() const throw(gpstk::InvalidRequest)
         { return getEpochTime(); }
     
         /** This function returns the PRN ID of the SV. */
      short getPRNID() const throw(gpstk::InvalidRequest);
      
         /** This function returns the tracker number. */
      short getTracker() const throw(gpstk::InvalidRequest);

         /** This function returns the time of the HOW in subframe
          * 1 or 2 or 3 in seconds of week. */
      double getHOWTime(short subframe) const throw(gpstk::InvalidRequest);
      
         /** This function returns the A-S alert flag for either
          * subframe 1 or 2 or 3. */
      short getASAlert(short subframe) const throw(gpstk::InvalidRequest);
      
         /** This function return the GPS week number for the
          * ephemeris.  this is the full GPS week (ie > 10 bits). */
      short getFullWeek() const throw(gpstk::InvalidRequest);
      
         /** This function returns the values of the L2 codes. */
      short getCodeFlags() const throw(gpstk::InvalidRequest);
      
         /** This function returns the value of the SV accuracy (m)
          * computed from the accuracy flag in the nav message, or
          * as set by the setAccuracy() method. */
      double getAccuracy() const throw(gpstk::InvalidRequest);

         /** This function returns the flag based on the SV accuracy
          * flag as it appears in the nav message. */
      short getAccFlag() const throw(gpstk::InvalidRequest);
      
         /** This function returns the value of the SV health flag. */
      short getHealth() const throw(gpstk::InvalidRequest);
      
         /** This function returns the value of the L2 P-code data
          * flag. */
      short getL2Pdata() const throw(gpstk::InvalidRequest);
      
         /** This function returns the IODC for the given PRN. */
      short getIODC() const throw(gpstk::InvalidRequest);
      
         /** This function return the IODE for the ephemeris. */
      short getIODE() const throw(gpstk::InvalidRequest);
      
         /** This function return the AODO for the ephemeris. */
      long getAODO() const throw(gpstk::InvalidRequest);
      
         /** This function returns the clock epoch in GPS seconds of
          * week. */
      double getToc() const throw(gpstk::InvalidRequest);
      
         /** This function returns the SV clock error in seconds. */