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Fix sign in Glonass tau_n_A parameter, improve almanac handling

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This commit is contained in:
Carles Fernandez
2025-11-24 23:56:01 +01:00
parent 6488d5a995
commit ba631253a8
1 changed files with 51 additions and 37 deletions
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88
src/core/system_parameters/glonass_gnav_navigation_message.cc
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@@ -110,18 +110,22 @@ bool Glonass_Gnav_Navigation_Message::CRC_test(std::bitset<GLONASS_GNAV_STRING_B
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)
const int32_t parity_sum = C1 + C2 + C3 + C4 + C5 + C6 + C7;
// Case 1: All checksums (C1,...,C7 and C_Sigma) are equal to zero
if ((parity_sum + C_Sigma) == 0)
{
return true;
}
if (C_Sigma && (sum_bits & 1))
// Case 2: Only one of the checksums (C1,...,C7) is equal to 1 and C_Sigma = 1
if (C_Sigma == 1 && parity_sum == 1)
{
return true;
}
// Case 3: C_Sigma = 1 and C1...C7 indicate a single bit error in the data field
if (C_Sigma == 1 && parity_sum > 0)
{
int32_t syndrome = C1;
syndrome |= (C2 ? 2 : 0);
@@ -130,16 +134,16 @@ bool Glonass_Gnav_Navigation_Message::CRC_test(std::bitset<GLONASS_GNAV_STRING_B
syndrome |= (C5 ? 16 : 0);
syndrome |= (C6 ? 32 : 0);
syndrome |= (C7 ? 64 : 0);
if (syndrome < 85)
if (syndrome < static_cast<int32_t>(GLONASS_GNAV_ECC_LOCATOR.size()))
{
// correct the bit in the data field
const int32_t locator = GLONASS_GNAV_ECC_LOCATOR[syndrome];
bits[locator] = !bits[locator];
return true;
}
else
{
return false;
}
return false;
}
// All other conditions are assumed errors.
@@ -173,7 +177,6 @@ int64_t Glonass_Gnav_Navigation_Message::read_navigation_signed(const std::bitse
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++)
@@ -189,23 +192,23 @@ uint32_t Glonass_Gnav_Navigation_Message::get_frame_number(uint32_t satellite_sl
{
uint32_t frame_ID = 0U;
if (satellite_slot_number >= 1 and satellite_slot_number <= 5)
if (satellite_slot_number >= 1 && satellite_slot_number <= 5)
{
frame_ID = 1U;
}
else if (satellite_slot_number >= 6 and satellite_slot_number <= 10)
else if (satellite_slot_number >= 6 && satellite_slot_number <= 10)
{
frame_ID = 2U;
}
else if (satellite_slot_number >= 11 and satellite_slot_number <= 15)
else if (satellite_slot_number >= 11 && satellite_slot_number <= 15)
{
frame_ID = 3U;
}
else if (satellite_slot_number >= 16 and satellite_slot_number <= 20)
else if (satellite_slot_number >= 16 && satellite_slot_number <= 20)
{
frame_ID = 4U;
}
else if (satellite_slot_number >= 21 and satellite_slot_number <= 24)
else if (satellite_slot_number >= 21 && satellite_slot_number <= 24)
{
frame_ID = 5U;
}
@@ -372,7 +375,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
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_tau_n_A = static_cast<double>(read_navigation_signed(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;
@@ -422,7 +425,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
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_tau_n_A = static_cast<double>(read_navigation_signed(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;
@@ -467,7 +470,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
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_tau_n_A = static_cast<double>(read_navigation_signed(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;
@@ -511,7 +514,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
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_tau_n_A = static_cast<double>(read_navigation_signed(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;
@@ -562,7 +565,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
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_tau_n_A = static_cast<double>(read_navigation_signed(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;
@@ -573,7 +576,7 @@ int32_t Glonass_Gnav_Navigation_Message::string_decoder(const std::string& frame
case 15:
// --- It is string 15 ----------------------------------------------
if (d_frame_ID != 5 and flag_almanac_str_14 == true)
if (d_frame_ID != 5 && 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;
@@ -614,8 +617,8 @@ bool Glonass_Gnav_Navigation_Message::have_new_ephemeris() // Check if we have
{
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
if ((flag_ephemeris_str_1 == true) && (flag_ephemeris_str_2 == true) &&
(flag_ephemeris_str_3 == true) && (flag_ephemeris_str_4 == true) &&
(flag_utc_model_str_5 == true))
{
if (d_previous_tb != gnav_ephemeris.d_t_b)
@@ -651,9 +654,15 @@ bool Glonass_Gnav_Navigation_Message::have_new_utc_model() // Check if we have
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 (i_alm_satellite_slot_number == 0 || i_alm_satellite_slot_number > GLONASS_CA_NBR_SATS)
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
return false;
}
const size_t idx = i_alm_satellite_slot_number - 1U;
if ((flag_almanac_str_6 == true) && (flag_almanac_str_7 == true))
{
if (d_previous_Na[idx] != gnav_utc_model.d_N_A)
{
// All Almanac data have been received for this satellite
flag_almanac_str_6 = false;
@@ -661,36 +670,36 @@ bool Glonass_Gnav_Navigation_Message::have_new_almanac() // Check if we have a
new_alm = true;
}
}
if ((flag_almanac_str_8 == true) and (flag_almanac_str_9 == true))
if ((flag_almanac_str_8 == true) && (flag_almanac_str_9 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
if (d_previous_Na[idx] != 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 ((flag_almanac_str_10 == true) && (flag_almanac_str_11 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
if (d_previous_Na[idx] != 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 ((flag_almanac_str_12 == true) && (flag_almanac_str_13 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
if (d_previous_Na[idx] != 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 ((flag_almanac_str_14 == true) && (flag_almanac_str_15 == true))
{
if (d_previous_Na[i_alm_satellite_slot_number] != gnav_utc_model.d_N_A)
if (d_previous_Na[idx] != gnav_utc_model.d_N_A)
{
flag_almanac_str_14 = false;
flag_almanac_str_15 = false;
@@ -698,5 +707,10 @@ bool Glonass_Gnav_Navigation_Message::have_new_almanac() // Check if we have a
}
}
if (new_alm)
{
d_previous_Na[idx] = gnav_utc_model.d_N_A;
}
return new_alm;
}