corrected user algorithms

src/core/system_parameters/beidou_cnav2_almanac.cc

@@ -57,3 +57,14 @@ Beidou_Cnav2_Almanac::Beidou_Cnav2_Almanac()
 	Phi_0 = 0.0;				//!< Argument of latitude at reference time
 	//Health = 0.0;				//!< Satellite health information
 }
+
+double Beidou_Cnav2_Almanac::BDS_time_of_transmission(double t_sv)
+{
+	double t;
+	double dt_sv;
+
+	dt_sv = a_f0 + a_f1 * (t-t_oa);
+
+	t = t_sv - dt_sv;
+	return t;
+}

src/core/system_parameters/beidou_cnav2_almanac.h

@@ -100,6 +100,7 @@ class Beidou_Cnav2_Almanac
         archive& make_nvp("Health", Health);
     }
 
+    double BDS_time_of_transmission(double t_sv);
     /*!
      * Default constructor
      */

src/core/system_parameters/beidou_cnav2_ephemeris.cc

@@ -98,18 +98,53 @@ Beidou_Cnav2_Ephemeris::Beidou_Cnav2_Ephemeris()
 	SISAI_oc2 = 0.0;	//Satellite clock drift accuracy index
 
 	// Ionospheric Delay Correction Model Parameters
-	alpha_1 = 0.0;
-	alpha_2 = 0.0;
-	alpha_3 = 0.0;
-	alpha_4 = 0.0;
-	alpha_5 = 0.0;
-	alpha_6 = 0.0;
-	alpha_7 = 0.0;
-	alpha_8 = 0.0;
-	alpha_9 = 0.0;
+	alpha_1 = 0.0;		//[TECu]
+	alpha_2 = 0.0;		//[TECu]
+	alpha_3 = 0.0;		//[TECu]
+	alpha_4 = 0.0;		//[TECu]
+	alpha_5 = 0.0;		//[TECu]
+	alpha_6 = 0.0;		//[TECu]
+	alpha_7 = 0.0;		//[TECu]
+	alpha_8 = 0.0;		//[TECu]
+	alpha_9 = 0.0;		//[TECu]
 
 	// Group Delay Differential Parameters
 	T_GDB1Cp = 0.0;	//Group delay differential of the B1C pilot component [s]
 	T_GDB2ap = 0.0;	//Group delay differential of the B2a pilot component [s]
 	ISC_B2ad = 0.0;	//Group delay differential between the B2a data and pilot components [s]
 }
+
+double Beidou_Cnav2_Ephemeris::B2a_ranging_code_phase_correction_w_pilot(double dt_sv)
+{
+	double dt_sv_B2ap;
+	dt_sv_B2ap = dt_sv - T_GDB2ap;
+	return dt_sv_B2ap;
+}
+
+double Beidou_Cnav2_Ephemeris::B2a_ranging_code_phase_correction_w_data(double dt_sv)
+{
+	double dt_sv_B2ad;
+	dt_sv_B2ad = dt_sv - T_GDB2ap - ISC_B2ad;
+	return dt_sv_B2ad;
+}
+
+double Beidou_Cnav2_Ephemeris::B2a_UT1_UTC_difference(double t)
+{
+	return dUT1 -dUT1_dot*(t-t_EOP);
+}
+
+double Beidou_Cnav2_Ephemeris::B2a_Polar_motion_x(double t)
+{
+	double x_p;
+
+	x_p = PM_X + PM_X_dot * (t-t_EOP);
+	return x_p;
+}
+
+double Beidou_Cnav2_Ephemeris::B2a_Polar_motion_y(double t)
+{
+	double y_p;
+
+	y_p = PM_Y + PM_Y_dot * (t-t_EOP);
+	return y_p;
+}

src/core/system_parameters/beidou_cnav2_ephemeris.h

@@ -197,22 +197,36 @@ class Beidou_Cnav2_Ephemeris
 		archive& make_nvp("SISAI_oc2", SISAI_oc2);	//Satellite clock drift accuracy index
 
 		// Ionospheric Delay Correction Model Parameters
-		archive& make_nvp("alpha_1", alpha_1);
-		archive& make_nvp("alpha_2", alpha_2);
-		archive& make_nvp("alpha_3", alpha_3);
-		archive& make_nvp("alpha_4", alpha_4);
-		archive& make_nvp("alpha_5", alpha_5);
-		archive& make_nvp("alpha_6", alpha_6);
-		archive& make_nvp("alpha_7", alpha_7);
-		archive& make_nvp("alpha_8", alpha_8);
-		archive& make_nvp("alpha_9", alpha_9);
+		archive& make_nvp("alpha_1", alpha_1);		// Ionosphere a1
+		archive& make_nvp("alpha_2", alpha_2);		// Ionosphere a2
+		archive& make_nvp("alpha_3", alpha_3);		// Ionosphere a3
+		archive& make_nvp("alpha_4", alpha_4);		// Ionosphere a4
+		archive& make_nvp("alpha_5", alpha_5);		// Ionosphere a5
+		archive& make_nvp("alpha_6", alpha_6);		// Ionosphere a6
+		archive& make_nvp("alpha_7", alpha_7);		// Ionosphere a7
+		archive& make_nvp("alpha_8", alpha_8);		// Ionosphere a8
+		archive& make_nvp("alpha_9", alpha_9);		// Ionosphere a9
 
 		// Group Delay Differential Parameters
 		archive& make_nvp("T_GDB1Cp", T_GDB1Cp);	//Group delay differential of the B1C pilot component [s]
 		archive& make_nvp("T_GDB2ap", T_GDB2ap);	//Group delay differential of the B2a pilot component [s]
 		archive& make_nvp("ISC_B2ad", ISC_B2ad);	//Group delay differential between the B2a data and pilot components [s]
     }
 
+    double B2a_ranging_code_phase_correction_w_pilot(double dt_sv);
+    // The single frequency user processing pseudorange from the B2a pilot component shall further correct the ranging code phase
+
+    double B2a_ranging_code_phase_correction_w_data(double dt_sv);
+    // The single frequency user processing pseudorange from the B2a data component shall further correct the ranging code phase
+
+    double B2a_UT1_UTC_difference(double t);
+    // UT1-UTC difference at time t
+
+    double B2a_Polar_motion_x(double t);
+    // Polar motion in the X-Axis at time t
+
+    double B2a_Polar_motion_y(double t);
+    // Polar motion in the Y-Axis at time t
 
     Beidou_Cnav2_Ephemeris();
 };

src/core/system_parameters/beidou_cnav2_navigation_message.cc

@@ -641,7 +641,5 @@ bool Beidou_Cnav2_Navigation_Message::have_new_almanac()  //Check if we have a n
                         return true;
                     }
             }
-
-    // todo  fix
     return false;
 }

src/core/system_parameters/beidou_cnav2_utc_model.cc

@@ -46,7 +46,7 @@ Beidou_Cnav2_Utc_Model::Beidou_Cnav2_Utc_Model()
 	WN_ot = 0.0;		//Reference week number [week]
 	WN_LSF = 0.0;		//Leap second reference week number [week]
 	DN = 0.0;			//Leap second reference day number [day]
-	dt_LSF = 0.0;		//Current of future leap second count [s]
+	dt_LSF = 0.0;		//Current or future leap second count [s]
 
 	// BDT-GNSS Time Offset Parameters
 	GNSS_ID = 0.0;		//GNSS type identification [dimensionless]
@@ -57,39 +57,67 @@ Beidou_Cnav2_Utc_Model::Beidou_Cnav2_Utc_Model()
 	A_2BGTO = 0.0;		//Drift rate coefficient of BDT time scale relative to GNSS time scale [s/s^2]
 
 	// Clock Correction Parameters
-	t_oc = 0.0;
-	a_0 = 0.0;
-	a_1 = 0.0;
-	a_2 = 0.0;
+	t_oc = 0.0;			//Clock correction parameters reference time [s] effective range 0~604500
+	a_0 = 0.0;			//Satellite clock time bias correction coefficient [s]
+	a_1 = 0.0;			//Satellite clock time drift correction coefficient [s/s]
+	a_2 = 0.0;			//Satellite clock time drift rate correction coefficient [s/s^2]
 }
 
-
-double Beidou_Cnav2_Utc_Model::utc_time(double beidou_time)
+double Beidou_Cnav2_Utc_Model::time_of_transmission(Beidou_Cnav2_Almanac const&alm, Beidou_Cnav2_Ephemeris const&eph, double t_sv)
 {
-    double t_utc;
+	double t;			// BDT time of signal transmission [s]
+	double dt_sv;		// Satellite ranging code phase time offset [s]
+	double dt_r;		// Relativistic correction term [s]
+
+	double mu;
+	double c;
+	double F;
+
+	double E_k;
+
+	c = 2.99792458e8;	// Speed of light [m/s]
+	mu = 3.986004418e14;	// Geocentric gravitational constant [m^3/s^2]
+	F = -2 *sqrt(mu) / (c * c);
 
-    t_utc = beidou_time + dt_LS;	// Adds the leap seconds that is broadcasted
+	dt_r = F * eph.e * alm.sqrt_A * sin(E_k);
 
-    return t_utc;
+	dt_sv = a_0 + a_1*(t-t_oc) + a_2*(t-t_oc)*(t-t_oc) + dt_r;
+
+	t = t_sv - dt_sv;
+
+	return t;
 }
 
-double Beidou_Cnav2_Utc_Model::beidt_to_utc(Beidou_Cnav2_Ephemeris const&eph)
+
+double Beidou_Cnav2_Utc_Model::beidt_to_utc(Beidou_Cnav2_Ephemeris const&eph, double t_E, double WN_E, double DN_E)
 {
 	double t_UTC;
 	double dt_UTC;
 	double W;
 
-     // 1) DN is not in the past
-	dt_UTC = dt_LS + A_0UTC + A_1UTC * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot)) + A_2UTC * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot)) * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot));
-	t_UTC = fmod((eph.t_oe - dt_UTC),86400);
-
-	 // 2) user's present time falls within the time span which starts six hours prior to the leap second time and ends six hours after the leap second time
-	W = fmod((eph.t_oe - dt_UTC - 43200),86400) + 43200;
-	t_UTC = fmod(W,(86400 + dt_LSF - dt_LS));
 
-     // 3) DN is in the past
-    dt_UTC = dt_LSF + A_0UTC + A_1UTC * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot)) + A_2UTC * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot)) * (eph.t_oe - t_ot + 604800 * (eph.WN - WN_ot));
-    t_UTC = fmod((eph.t_oe - dt_UTC),86400);
+	// DN is not in the past
+	if ((WN_LSF - WN_E)*7 + (DN - DN_E) > 0)
+	{
+		if (abs(dt_LSF) > 6*3600)
+		{
+			// 1) user's present time does not fall within the time span which starts six hours prior to the leap second time and ends six hours after the leap second time
+			dt_UTC = dt_LS + A_0UTC + A_1UTC * (t_E - t_ot + 604800 * (WN_E - WN_ot)) + A_2UTC * (t_E - t_ot + 604800 * (WN_E - WN_ot)) * (t_E - t_ot + 604800 * (WN_E - WN_ot));
+			t_UTC = fmod((t_E - dt_UTC),86400);
+		}
+		else
+		{
+			// 2) user's present time falls within the time span which starts six hours prior to the leap second time and ends six hours after the leap second time
+			W = fmod((t_E - dt_UTC - 43200),86400) + 43200;
+			t_UTC = fmod(W,(86400 + dt_LSF - dt_LS));
+		}
+	}
+	else
+	{
+		 // 3) DN is in the past
+		dt_UTC = dt_LSF + A_0UTC + A_1UTC * (t_E - t_ot + 604800 * (WN_E - WN_ot)) + A_2UTC * (t_E - t_ot + 604800 * (WN_E - WN_ot)) * (t_E - t_ot + 604800 * (WN_E - WN_ot));
+		t_UTC = fmod((t_E - dt_UTC),86400);
+	}
 
     return t_UTC;
 }

src/core/system_parameters/beidou_cnav2_utc_model.h

@@ -37,6 +37,7 @@
 #include <boost/assign.hpp>
 #include <boost/serialization/nvp.hpp>
 #include "beidou_cnav2_ephemeris.h"
+#include "beidou_cnav2_almanac.h"
 
 //!!! Check
 /*!
@@ -70,10 +71,10 @@ class Beidou_Cnav2_Utc_Model
 	double A_2BGTO;		//Drift rate coefficient of BDT time scale relative to GNSS time scale [s/s^2]
 
 	// Clock Correction Parameters
-	double t_oc;
-	double a_0;
-	double a_1;
-	double a_2;
+	double t_oc;		//Clock correction parameters reference time [s] effective range 0~604500
+	double a_0;			//Satellite clock time bias correction coefficient [s]
+	double a_1;			//Satellite clock time drift correction coefficient [s/s]
+	double a_2;			//Satellite clock time drift rate correction coefficient [s/s^2]
 
     template <class Archive>
     /*!
@@ -113,34 +114,20 @@ class Beidou_Cnav2_Utc_Model
         archive& make_nvp("a_2", a_2);
     }
 
-    double beidt_to_gpst(const double offset_time, const double glot2utc_corr);
-
-    /*!
-     * \brief Converts from BEIDOUT to GPST
-     * \details Converts from BEIDOUT to GPST in time of week (TOW) and week number (WN) format
-     * \param[in] tod_offset Is the start of day offset
-     * \param[in] beidt2utc_corr Correction from BEIDOUT to UTC
-     * \param[in] beidt2gpst_corr Correction from BEIDOUT to GPST
-     * \param[out] WN Week Number, not in mod(1024) format
-     * \param[out] TOW Time of Week in seconds of week
-     */
-    double beidt_to_utc(Beidou_Cnav2_Ephemeris const&eph);
+    double time_of_transmission(Beidou_Cnav2_Almanac const&alm, Beidou_Cnav2_Ephemeris const&eph, double t_sv);
 
+    double beidt_to_gpst(Beidou_Cnav2_Ephemeris const&eph, double beidou_time);
 
     /*!
      * \brief Converts from BEIDOUT to GPST
-     * \details Converts from BEIDOUT to GPST in time of week (TOW) and week number (WN) format
-     * \param[in] tod_offset Is the start of day offset
-     * \param[in] beidt2utc_corr Correction from BEIDOUT to UTC
-     * \param[in] beidt2gpst_corr Correction from BEIDOUT to GPST
-     * \param[out] WN Week Number, not in mod(1024) format
-     * \param[out] TOW Time of Week in seconds of week
+
      */
+    double beidt_to_utc(Beidou_Cnav2_Ephemeris const&eph, double t_E, double WN_E, double DN_E);
 
-    double beidt_to_gpst(const Beidou_Cnav2_Ephemeris &eph, double beid_time);
 
     /*!
-     * Default constructor
+     * \brief Converts from BEIDOUT to UTC
+     * The t_E, WN_E, DN_E are the BDT estimated by the user
      */
 
     double utc_time(double beidou_time);