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/*!
* \file glonass_gnav_navigation_message.cc
* \brief Implementation of a GLONASS GNAV Data message decoder as described in GLONASS ICD (Edition 5.1)
* \note Code added as part of GSoC 2017 program
* \author Damian Miralles, 2017. dmiralles2009(at)gmail.com
* \see <a href="http://russianspacesystems.ru/wp-content/uploads/2016/08/ICD_GLONASS_eng_v5.1.pdf">GLONASS ICD</a>
*
* -----------------------------------------------------------------------------
*
* GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
* This file is part of GNSS-SDR.
*
* Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)
* SPDX-License-Identifier: GPL-3.0-or-later
*
* -----------------------------------------------------------------------------
*/
#include "glonass_gnav_navigation_message.h"
#include "MATH_CONSTANTS.h" // for TWO_N20, TWO_N30, TWO_N14, TWO_N15, TWO_N18
#include "gnss_satellite.h"
#include <glog/logging.h>
#include <cstddef> // for size_t
#include <ostream> // for operator<<
Glonass_Gnav_Navigation_Message::Glonass_Gnav_Navigation_Message()
{
auto gnss_sat = Gnss_Satellite();
std::string _system("GLONASS");
// TODO SHould number of channels be hardcoded?
for (uint32_t i = 1; i < 14; i++)
{
satelliteBlock[i] = gnss_sat.what_block(_system, i);
}
}
bool Glonass_Gnav_Navigation_Message::CRC_test(std::bitset<GLONASS_GNAV_STRING_BITS>& bits) const
{
uint32_t sum_bits = 0;
int32_t sum_hamming = 0;
std::vector<uint32_t> string_bits(GLONASS_GNAV_STRING_BITS);
// Populate data and hamming code vectors
for (size_t i = 0; i < string_bits.size(); i++)
{
string_bits[i] = static_cast<uint32_t>(bits[i]);
}
// Compute C1 term
sum_bits = 0;
for (int i : GLONASS_GNAV_CRC_I_INDEX)
{
sum_bits += string_bits[i - 1];
}
const int32_t C1 = string_bits[0] ^ (sum_bits % 2);
// Compute C2 term
sum_bits = 0;
for (int j : GLONASS_GNAV_CRC_J_INDEX)
{
sum_bits += string_bits[j - 1];
}
const int32_t C2 = (string_bits[1]) ^ (sum_bits % 2);
// Compute C3 term
sum_bits = 0;
for (int k : GLONASS_GNAV_CRC_K_INDEX)
{
sum_bits += string_bits[k - 1];
}
const int32_t C3 = string_bits[2] ^ (sum_bits % 2);
// Compute C4 term
sum_bits = 0;
for (int l : GLONASS_GNAV_CRC_L_INDEX)
{
sum_bits += string_bits[l - 1];
}
const int32_t C4 = string_bits[3] ^ (sum_bits % 2);
// Compute C5 term
sum_bits = 0;
for (int m : GLONASS_GNAV_CRC_M_INDEX)
{
sum_bits += string_bits[m - 1];
}
const int32_t C5 = string_bits[4] ^ (sum_bits % 2);
// Compute C6 term
sum_bits = 0;
for (int n : GLONASS_GNAV_CRC_N_INDEX)
{
sum_bits += string_bits[n - 1];
}
const int32_t C6 = string_bits[5] ^ (sum_bits % 2);
// Compute C7 term
sum_bits = 0;
for (int p : GLONASS_GNAV_CRC_P_INDEX)
{
sum_bits += string_bits[p - 1];
}
const int32_t C7 = string_bits[6] ^ (sum_bits % 2);
// Compute C_Sigma term
sum_bits = 0;
for (int q : GLONASS_GNAV_CRC_Q_INDEX)
{
sum_bits += string_bits[q - 1];
}
for (int32_t q = 0; q < 8; q++)
{
sum_hamming += string_bits[q];
}
const int32_t C_Sigma = (sum_hamming % 2) ^ (sum_bits % 2);
// Verification of the data
// (a-i) All checksums (C1,...,C7 and C_Sigma) are equal to zero
if ((C1 + C2 + C3 + C4 + C5 + C6 + C7 + C_Sigma) == 0)
{
return true;
}
// (a-ii) Only one of the checksums (C1,...,C7) is equal to 1 and C_Sigma = 1
if (C_Sigma == 1 && C1 + C2 + C3 + C4 + C5 + C6 + C7 == 1)
{
return true;
}
if (C_Sigma && (sum_bits & 1))
{
int32_t syndrome = C1;
syndrome |= (C2 ? 2 : 0);
syndrome |= (C3 ? 4 : 0);
syndrome |= (C4 ? 8 : 0);
syndrome |= (C5 ? 16 : 0);
syndrome |= (C6 ? 32 : 0);
syndrome |= (C7 ? 64 : 0);
if (syndrome < 85)
{
const int32_t locator = GLONASS_GNAV_ECC_LOCATOR[syndrome];
bits[locator] = !bits[locator];
return true;
}
else
{
return false;
}
}
// All other conditions are assumed errors.
return false;
}
bool Glonass_Gnav_Navigation_Message::read_navigation_bool(const std::bitset<GLONASS_GNAV_STRING_BITS>& bits, const std::vector<std::pair<int32_t, int32_t>>& parameter) const
{
bool value = bits[GLONASS_GNAV_STRING_BITS - parameter[0].first];
return value;
}
uint64_t Glonass_Gnav_Navigation_Message::read_navigation_unsigned(const std::bitset<GLONASS_GNAV_STRING_BITS>& bits, const std::vector<std::pair<int32_t, int32_t>>& parameter) const
{
uint64_t value = 0ULL;
for (const auto& p : parameter)
{
for (int32_t j = 0; j < p.second; j++)
{
value = (value << 1U) | static_cast<uint64_t>(bits[GLONASS_GNAV_STRING_BITS - p.first - j]);
}
}
return value;
}
int64_t Glonass_Gnav_Navigation_Message::read_navigation_signed(const std::bitset<GLONASS_GNAV_STRING_BITS>& bits, const std::vector<std::pair<int32_t, int32_t>>& parameter) const
{
int64_t value = 0LL;
int64_t sign = (bits[GLONASS_GNAV_STRING_BITS - parameter[0].first] == 1) ? -1LL : 1LL;
// const int32_t num_of_slices = parameter.size();
for (const auto& p : parameter)
{
for (int32_t j = 1; j < p.second; j++)
{
value = (value << 1) + bits[GLONASS_GNAV_STRING_BITS - p.first - j];
}
}
return (sign * value);
}
uint32_t Glonass_Gnav_Navigation_Message::get_frame_number(uint32_t satellite_slot_number)
{
uint32_t frame_ID = 0U;
if (satellite_slot_number >= 1 and satellite_slot_number <= 5)
{
frame_ID = 1U;
}
else if (satellite_slot_number >= 6 and satellite_slot_number <= 10)
{
frame_ID = 2U;
}
else if (satellite_slot_number >= 11 and satellite_slot_number <= 15)
{
frame_ID = 3U;
}
else if (satellite_slot_number >= 16 and satellite_slot_number <= 20)
{
frame_ID = 4U;
}
else if (satellite_slot_number >= 21 and satellite_slot_number <= 24)
{
frame_ID = 5U;
}
else
{
LOG(WARNING) << "GLONASS GNAV: Invalid Satellite Slot Number";
frame_ID = 0U;
}
return frame_ID;
}
int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame_string)
{
int32_t J = 0;
d_frame_ID = 0U;
uint64_t P_1_tmp = 0;
// Unpack bytes to bits
std::bitset<GLONASS_GNAV_STRING_BITS> string_bits(frame_string);
// Perform data verification and exit code if error in bit sequence
flag_CRC_test = CRC_test(string_bits);
if (flag_CRC_test == false)
{
return 0;
}
// Decode all 15 string messages
d_string_ID = static_cast<uint32_t>(read_navigation_unsigned(string_bits, STRING_ID));
switch (d_string_ID)
{
case 1:
// --- It is string 1 -----------------------------------------------
P_1_tmp = read_navigation_unsigned(string_bits, P1);
gnav_ephemeris.d_P_1 = (P_1_tmp == 0) ? 0. : (P_1_tmp + 1) * 15;
gnav_ephemeris.d_t_k = static_cast<double>(read_navigation_unsigned(string_bits, T_K_HR)) * 3600 +
static_cast<double>(read_navigation_unsigned(string_bits, T_K_MIN)) * 60 +
static_cast<double>(read_navigation_unsigned(string_bits, T_K_SEC)) * 30;
gnav_ephemeris.d_VXn = static_cast<double>(read_navigation_signed(string_bits, X_N_DOT)) * TWO_N20;
gnav_ephemeris.d_AXn = static_cast<double>(read_navigation_signed(string_bits, X_N_DOT_DOT)) * TWO_N30;
gnav_ephemeris.d_Xn = static_cast<double>(read_navigation_signed(string_bits, X_N)) * TWO_N11;
flag_ephemeris_str_1 = true;
break;
case 2:
// --- It is string 2 -----------------------------------------------
if (flag_ephemeris_str_1 == true)
{
gnav_ephemeris.d_B_n = static_cast<double>(read_navigation_unsigned(string_bits, B_N));
gnav_ephemeris.d_P_2 = read_navigation_bool(string_bits, P2);
gnav_ephemeris.d_t_b = static_cast<double>(read_navigation_unsigned(string_bits, T_B)) * 15 * 60;
gnav_ephemeris.d_VYn = static_cast<double>(read_navigation_signed(string_bits, Y_N_DOT)) * TWO_N20;
gnav_ephemeris.d_AYn = static_cast<double>(read_navigation_signed(string_bits, Y_N_DOT_DOT)) * TWO_N30;
gnav_ephemeris.d_Yn = static_cast<double>(read_navigation_signed(string_bits, Y_N)) * TWO_N11;
gnav_ephemeris.d_iode = read_navigation_unsigned(string_bits, T_B);
flag_ephemeris_str_2 = true;
}
break;
case 3:
// --- It is string 3 ----------------------------------------------
if (flag_ephemeris_str_2 == true)
{
gnav_ephemeris.d_P_3 = read_navigation_bool(string_bits, P3);
gnav_ephemeris.d_gamma_n = static_cast<double>(read_navigation_signed(string_bits, GAMMA_N)) * TWO_N40;
gnav_ephemeris.d_P = static_cast<double>(read_navigation_unsigned(string_bits, P));
gnav_ephemeris.d_l3rd_n = read_navigation_bool(string_bits, EPH_L_N);
gnav_ephemeris.d_VZn = static_cast<double>(read_navigation_signed(string_bits, Z_N_DOT)) * TWO_N20;
gnav_ephemeris.d_AZn = static_cast<double>(read_navigation_signed(string_bits, Z_N_DOT_DOT)) * TWO_N30;
gnav_ephemeris.d_Zn = static_cast<double>(read_navigation_signed(string_bits, Z_N)) * TWO_N11;
flag_ephemeris_str_3 = true;
}
break;
case 4:
// --- It is string 4 ----------------------------------------------
if (flag_ephemeris_str_3 == true)
{
gnav_ephemeris.d_tau_n = static_cast<double>(read_navigation_signed(string_bits, TAU_N)) * TWO_N30;
gnav_ephemeris.d_Delta_tau_n = static_cast<double>(read_navigation_signed(string_bits, DELTA_TAU_N)) * TWO_N30;
gnav_ephemeris.d_E_n = static_cast<double>(read_navigation_unsigned(string_bits, E_N));
gnav_ephemeris.d_P_4 = read_navigation_bool(string_bits, P4);
gnav_ephemeris.d_F_T = static_cast<double>(read_navigation_unsigned(string_bits, F_T));
gnav_ephemeris.d_N_T = static_cast<double>(read_navigation_unsigned(string_bits, N_T));
gnav_ephemeris.d_n = static_cast<double>(read_navigation_unsigned(string_bits, N));
gnav_ephemeris.d_M = static_cast<double>(read_navigation_unsigned(string_bits, M));
// Fill in ephemeris deliverables in the code
flag_update_slot_number = true;
gnav_ephemeris.i_satellite_slot_number = static_cast<uint32_t>(gnav_ephemeris.d_n);
gnav_ephemeris.PRN = static_cast<uint32_t>(gnav_ephemeris.d_n);
flag_ephemeris_str_4 = true;
}
break;
case 5:
// --- It is string 5 ----------------------------------------------
if (flag_ephemeris_str_4 == true)
{
gnav_utc_model.d_N_A = static_cast<double>(read_navigation_unsigned(string_bits, DAY_NUMBER_A));
gnav_utc_model.d_tau_c = static_cast<double>(read_navigation_signed(string_bits, TAU_C)) * TWO_N31;
gnav_utc_model.d_N_4 = static_cast<double>(read_navigation_unsigned(string_bits, N_4));
gnav_utc_model.d_tau_gps = static_cast<double>(read_navigation_signed(string_bits, TAU_GPS)) * TWO_N30;
gnav_ephemeris.d_l5th_n = read_navigation_bool(string_bits, ALM_L_N);
flag_utc_model_str_5 = true;
// Compute Year and DoY based on Algorithm A3.11 of GLONASS ICD
// 1). Current year number J in the four-year interval is calculated
if (gnav_ephemeris.d_N_T >= 1 && gnav_ephemeris.d_N_T <= 366)
{
J = 1;
}
else if (gnav_ephemeris.d_N_T >= 367 && gnav_ephemeris.d_N_T <= 731)
{
J = 2;
}
else if (gnav_ephemeris.d_N_T >= 732 && gnav_ephemeris.d_N_T <= 1096)
{
J = 3;
}
else if (gnav_ephemeris.d_N_T >= 1097 && gnav_ephemeris.d_N_T <= 1461)
{
J = 4;
}
// 2). Current year in common form is calculated by the following formula:
gnav_ephemeris.d_yr = 1996 + 4.0 * (gnav_utc_model.d_N_4 - 1.0) + (J - 1.0);
gnav_ephemeris.d_tau_c = gnav_utc_model.d_tau_c;
// 3). Set TOW once the year has been defined, it helps with leap second determination
if (flag_ephemeris_str_1 == true)
{
gnav_ephemeris.glot_to_gpst(gnav_ephemeris.d_t_k + 10, gnav_utc_model.d_tau_c, gnav_utc_model.d_tau_gps, &gnav_ephemeris.d_WN, &gnav_ephemeris.d_TOW);
flag_TOW_set = true;
flag_TOW_new = true;
}
// 4) Set time of day (tod) when ephemeris data is complety decoded
gnav_ephemeris.d_tod = gnav_ephemeris.d_t_k + 2 * d_string_ID;
}
break;
case 6:
// --- It is string 6 ----------------------------------------------
i_alm_satellite_slot_number = static_cast<uint32_t>(read_navigation_unsigned(string_bits, N_A));
d_frame_ID = get_frame_number(i_alm_satellite_slot_number);
// Make sure a valid frame_ID or satellite slot number is returned
if (d_frame_ID == 0)
{
return 0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].d_C_n = read_navigation_bool(string_bits, C_N);
gnav_almanac[i_alm_satellite_slot_number - 1].d_M_n_A = static_cast<double>(read_navigation_unsigned(string_bits, M_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A = static_cast<double>(read_navigation_unsigned(string_bits, N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_tau_n_A = static_cast<double>(read_navigation_unsigned(string_bits, TAU_N_A)) * TWO_N18;
gnav_almanac[i_alm_satellite_slot_number - 1].d_lambda_n_A = static_cast<double>(read_navigation_signed(string_bits, LAMBDA_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_i_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_I_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_epsilon_n_A = static_cast<double>(read_navigation_unsigned(string_bits, EPSILON_N_A)) * TWO_N20;
flag_almanac_str_6 = true;
break;
case 7:
// --- It is string 7 ----------------------------------------------
if (flag_almanac_str_6 == true)
{
gnav_almanac[i_alm_satellite_slot_number - 1].d_omega_n_A = static_cast<double>(read_navigation_signed(string_bits, OMEGA_N_A)) * TWO_N15 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_t_lambda_n_A = static_cast<double>(read_navigation_unsigned(string_bits, T_LAMBDA_N_A)) * TWO_N5;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_N_A)) * TWO_N9;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A_dot = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_DOT_N_A)) * TWO_N14;
gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A = static_cast<double>(read_navigation_unsigned(string_bits, H_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_l_n = read_navigation_bool(string_bits, ALM_L_N);
// Set satellite information for redundancy purposes
if (gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A > 24)
{
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A - 32.0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_slot_number = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
gnav_almanac[i_alm_satellite_slot_number - 1].PRN = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
if (i_alm_satellite_slot_number == gnav_ephemeris.i_satellite_slot_number)
{
gnav_ephemeris.i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel;
}
flag_almanac_str_7 = true;
}
break;
case 8:
// --- It is string 8 ----------------------------------------------
i_alm_satellite_slot_number = static_cast<uint32_t>(read_navigation_unsigned(string_bits, N_A));
d_frame_ID = get_frame_number(i_alm_satellite_slot_number);
// Make sure a valid frame_ID or satellite slot number is returned
if (d_frame_ID == 0)
{
return 0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].d_C_n = read_navigation_bool(string_bits, C_N);
gnav_almanac[i_alm_satellite_slot_number - 1].d_M_n_A = static_cast<double>(read_navigation_unsigned(string_bits, M_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A = static_cast<double>(read_navigation_unsigned(string_bits, N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_tau_n_A = static_cast<double>(read_navigation_unsigned(string_bits, TAU_N_A)) * TWO_N18;
gnav_almanac[i_alm_satellite_slot_number - 1].d_lambda_n_A = static_cast<double>(read_navigation_signed(string_bits, LAMBDA_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_i_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_I_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_epsilon_n_A = static_cast<double>(read_navigation_unsigned(string_bits, EPSILON_N_A)) * TWO_N20;
flag_almanac_str_8 = true;
break;
case 9:
// --- It is string 9 ----------------------------------------------
if (flag_almanac_str_8 == true)
{
gnav_almanac[i_alm_satellite_slot_number - 1].d_omega_n_A = static_cast<double>(read_navigation_signed(string_bits, OMEGA_N_A)) * TWO_N15 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_t_lambda_n_A = static_cast<double>(read_navigation_unsigned(string_bits, T_LAMBDA_N_A)) * TWO_N5;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_N_A)) * TWO_N9;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A_dot = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_DOT_N_A)) * TWO_N14;
gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A = static_cast<double>(read_navigation_unsigned(string_bits, H_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_l_n = read_navigation_bool(string_bits, ALM_L_N);
// Set satellite information for redundancy purposes
if (gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A > 24)
{
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A - 32.0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_slot_number = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
gnav_almanac[i_alm_satellite_slot_number - 1].PRN = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
flag_almanac_str_9 = true;
}
break;
case 10:
// --- It is string 10 ---------------------------------------------
i_alm_satellite_slot_number = static_cast<uint32_t>(read_navigation_unsigned(string_bits, N_A));
d_frame_ID = get_frame_number(i_alm_satellite_slot_number);
// Make sure a valid frame_ID or satellite slot number is returned
if (d_frame_ID == 0)
{
return 0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].d_C_n = read_navigation_bool(string_bits, C_N);
gnav_almanac[i_alm_satellite_slot_number - 1].d_M_n_A = static_cast<double>(read_navigation_unsigned(string_bits, M_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A = static_cast<double>(read_navigation_unsigned(string_bits, N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_tau_n_A = static_cast<double>(read_navigation_unsigned(string_bits, TAU_N_A)) * TWO_N18;
gnav_almanac[i_alm_satellite_slot_number - 1].d_lambda_n_A = static_cast<double>(read_navigation_signed(string_bits, LAMBDA_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_i_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_I_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_epsilon_n_A = static_cast<double>(read_navigation_unsigned(string_bits, EPSILON_N_A)) * TWO_N20;
flag_almanac_str_10 = true;
break;
case 11:
// --- It is string 11 ---------------------------------------------
if (flag_almanac_str_10 == true)
{
gnav_almanac[i_alm_satellite_slot_number - 1].d_omega_n_A = static_cast<double>(read_navigation_signed(string_bits, OMEGA_N_A)) * TWO_N15 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_t_lambda_n_A = static_cast<double>(read_navigation_unsigned(string_bits, T_LAMBDA_N_A)) * TWO_N5;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_N_A)) * TWO_N9;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A_dot = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_DOT_N_A)) * TWO_N14;
gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A = static_cast<double>(read_navigation_unsigned(string_bits, H_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_l_n = read_navigation_bool(string_bits, ALM_L_N);
// Set satellite information for redundancy purposes
if (gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A > 24)
{
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A - 32.0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_slot_number = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
gnav_almanac[i_alm_satellite_slot_number - 1].PRN = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
flag_almanac_str_11 = true;
}
break;
case 12:
// --- It is string 12 ---------------------------------------------
i_alm_satellite_slot_number = static_cast<uint32_t>(read_navigation_unsigned(string_bits, N_A));
d_frame_ID = get_frame_number(i_alm_satellite_slot_number);
// Make sure a valid frame_ID or satellite slot number is returned
if (d_frame_ID == 0)
{
return 0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].d_C_n = read_navigation_bool(string_bits, C_N);
gnav_almanac[i_alm_satellite_slot_number - 1].d_M_n_A = static_cast<double>(read_navigation_unsigned(string_bits, M_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A = static_cast<double>(read_navigation_unsigned(string_bits, N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_tau_n_A = static_cast<double>(read_navigation_unsigned(string_bits, TAU_N_A)) * TWO_N18;
gnav_almanac[i_alm_satellite_slot_number - 1].d_lambda_n_A = static_cast<double>(read_navigation_signed(string_bits, LAMBDA_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_i_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_I_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_epsilon_n_A = static_cast<double>(read_navigation_unsigned(string_bits, EPSILON_N_A)) * TWO_N20;
flag_almanac_str_12 = true;
break;
case 13:
// --- It is string 13 ---------------------------------------------
if (flag_almanac_str_12 == true)
{
gnav_almanac[i_alm_satellite_slot_number - 1].d_omega_n_A = static_cast<double>(read_navigation_signed(string_bits, OMEGA_N_A)) * TWO_N15 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_t_lambda_n_A = static_cast<double>(read_navigation_unsigned(string_bits, T_LAMBDA_N_A)) * TWO_N5;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_N_A)) * TWO_N9;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A_dot = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_DOT_N_A)) * TWO_N14;
gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A = static_cast<double>(read_navigation_unsigned(string_bits, H_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_l_n = read_navigation_bool(string_bits, ALM_L_N);
// Set satellite information for redundancy purposes
if (gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A > 24)
{
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A - 32.0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_slot_number = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
gnav_almanac[i_alm_satellite_slot_number - 1].PRN = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
flag_almanac_str_13 = true;
}
break;
case 14:
// --- It is string 14 ---------------------------------------------
if (d_frame_ID == 5)
{
gnav_utc_model.d_B1 = static_cast<double>(read_navigation_unsigned(string_bits, B1));
gnav_utc_model.d_B2 = static_cast<double>(read_navigation_unsigned(string_bits, B2));
}
else
{
i_alm_satellite_slot_number = static_cast<uint32_t>(read_navigation_unsigned(string_bits, N_A));
d_frame_ID = get_frame_number(i_alm_satellite_slot_number);
// Make sure a valid frame_ID or satellite slot number is returned
if (d_frame_ID == 0)
{
return 0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].d_C_n = read_navigation_bool(string_bits, C_N);
gnav_almanac[i_alm_satellite_slot_number - 1].d_M_n_A = static_cast<double>(read_navigation_unsigned(string_bits, M_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A = static_cast<double>(read_navigation_unsigned(string_bits, N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_tau_n_A = static_cast<double>(read_navigation_unsigned(string_bits, TAU_N_A)) * TWO_N18;
gnav_almanac[i_alm_satellite_slot_number - 1].d_lambda_n_A = static_cast<double>(read_navigation_signed(string_bits, LAMBDA_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_i_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_I_N_A)) * TWO_N20 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_epsilon_n_A = static_cast<double>(read_navigation_unsigned(string_bits, EPSILON_N_A)) * TWO_N20;
flag_almanac_str_14 = true;
}
break;
case 15:
// --- It is string 15 ----------------------------------------------
if (d_frame_ID != 5 and flag_almanac_str_14 == true)
{
gnav_almanac[i_alm_satellite_slot_number - 1].d_omega_n_A = static_cast<double>(read_navigation_signed(string_bits, OMEGA_N_A)) * TWO_N15 * GNSS_PI;
gnav_almanac[i_alm_satellite_slot_number - 1].d_t_lambda_n_A = static_cast<double>(read_navigation_unsigned(string_bits, T_LAMBDA_N_A)) * TWO_N5;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_N_A)) * TWO_N9;
gnav_almanac[i_alm_satellite_slot_number - 1].d_Delta_T_n_A_dot = static_cast<double>(read_navigation_signed(string_bits, DELTA_T_DOT_N_A)) * TWO_N14;
gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A = static_cast<double>(read_navigation_unsigned(string_bits, H_N_A));
gnav_almanac[i_alm_satellite_slot_number - 1].d_l_n = read_navigation_bool(string_bits, ALM_L_N);
// Set satellite information for redundancy purposes
if (gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A > 24)
{
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_freq_channel = gnav_almanac[i_alm_satellite_slot_number - 1].d_H_n_A - 32.0;
}
gnav_almanac[i_alm_satellite_slot_number - 1].i_satellite_slot_number = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
gnav_almanac[i_alm_satellite_slot_number - 1].PRN = gnav_almanac[i_alm_satellite_slot_number - 1].d_n_A;
flag_almanac_str_15 = true;
}
break;
default:
LOG(INFO) << "GLONASS GNAV: Invalid String ID of received. Received " << d_string_ID
<< ", but acceptable range is from 1-15";
break;
} // switch string ID
return d_string_ID;
}
Glonass_Gnav_Almanac Glonass_Gnav_Navigation_Message::get_almanac(uint32_t satellite_slot_number) const
{
return gnav_almanac[satellite_slot_number - 1];
}
bool Glonass_Gnav_Navigation_Message::have_new_ephemeris() // Check if we have a new ephemeris stored in the galileo navigation class
{
bool new_eph = false;
// We need to make sure we have received the ephemeris info plus the time info
if ((flag_ephemeris_str_1 == true) and (flag_ephemeris_str_2 == true) and
(flag_ephemeris_str_3 == true) and (flag_ephemeris_str_4 == true) and
(flag_utc_model_str_5 == true))
{
if (d_previous_tb != gnav_ephemeris.d_t_b)
{
flag_ephemeris_str_1 = false; // clear the flag
flag_ephemeris_str_2 = false; // clear the flag
flag_ephemeris_str_3 = false; // clear the flag
flag_ephemeris_str_4 = false; // clear the flag
flag_all_ephemeris = true;
// Update the time of ephemeris information
d_previous_tb = gnav_ephemeris.d_t_b;
DLOG(INFO) << "GLONASS GNAV Ephemeris (1, 2, 3, 4) have been received and belong to the same batch";
new_eph = true;
}
}
return new_eph;
}
bool Glonass_Gnav_Navigation_Message::have_new_utc_model() // Check if we have a new utc data set stored in the galileo navigation class
{
if (flag_utc_model_str_5 == true)
{
flag_utc_model_str_5 = false; // clear the flag
return true;
}
return false;
}
bool Glonass_Gnav_Navigation_Message::have_new_almanac() // Check if we have a new almanac data set stored in the galileo navigation class
{
bool new_alm = false;
if ((flag_almanac_str_6 == true) and (flag_almanac_str_7 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
{
// All Almanac data have been received for this satellite
flag_almanac_str_6 = false;
flag_almanac_str_7 = false;
new_alm = true;
}
}
if ((flag_almanac_str_8 == true) and (flag_almanac_str_9 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
{
flag_almanac_str_8 = false;
flag_almanac_str_9 = false;
new_alm = true;
}
}
if ((flag_almanac_str_10 == true) and (flag_almanac_str_11 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
{
flag_almanac_str_10 = false;
flag_almanac_str_11 = false;
new_alm = true;
}
}
if ((flag_almanac_str_12 == true) and (flag_almanac_str_13 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
{
flag_almanac_str_12 = false;
flag_almanac_str_13 = false;
new_alm = true;
}
}
if ((flag_almanac_str_14 == true) and (flag_almanac_str_15 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
{
flag_almanac_str_14 = false;
flag_almanac_str_15 = false;
new_alm = true;
}
}
return new_alm;
}
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