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Split prs code phase into int and fract parts

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Applied to the VEML tracking. Previous commit was DE tracking only.
This commit is contained in:
Cillian O'Driscoll
2015-11-22 08:40:39 +00:00
parent 9d2739935d
commit 6eaad8f8a3
2 changed files with 63 additions and 29 deletions
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88
src/algorithms/tracking/gnuradio_blocks/galileo_e1_prs_veml_tracking_cc.cc
View File

@@ -258,7 +258,8 @@ galileo_e1_prs_veml_tracking_cc::galileo_e1_prs_veml_tracking_cc(
d_code_phase_chips = 0.0;
d_rem_code_phase_samples_prs = 0.0;
d_code_phase_chips_prs = 0.0;
d_integer_code_phase_chips_prs = 0;
d_fractional_code_phase_chips_prs = 0.0;
// Residual carrier phase
d_rem_carr_phase_rad = 0.0;
@@ -519,15 +520,15 @@ void galileo_e1_prs_veml_tracking_cc::update_local_code_prs()
// Update the local PRS code if necessary:
uint64_t last_code_phase_store = d_start_index_prs_code + d_size_prs_code;
uint64_t last_code_phase_required = static_cast< uint64_t >(
d_code_phase_chips_prs + code_phase_step_chips*d_current_prn_length_samples );
uint64_t last_code_phase_required = d_integer_code_phase_chips_prs + static_cast< uint64_t >(
d_fractional_code_phase_chips_prs + code_phase_step_chips*d_current_prn_length_samples );
if( !d_prs_code_initialized || ( last_code_phase_required > last_code_phase_store - 2 ) )
{
// Make sure we go back at least 2 chips:
d_start_index_prs_code = ( d_code_phase_chips_prs < 2.0 ?
static_cast<uint64_t>( std::floor( d_code_phase_chips_prs ) ) + d_prs_code_gen->get_code_length() - 2 :
static_cast<uint64_t>( std::floor( d_code_phase_chips_prs) ) - 2 );
d_start_index_prs_code = ( d_integer_code_phase_chips_prs < 2 ?
d_integer_code_phase_chips_prs + d_prs_code_gen->get_code_length() - 2 :
d_integer_code_phase_chips_prs - 2 );
d_prs_code_gen->get_chips(d_start_index_prs_code, d_size_prs_code, d_prs_code_shorts );
@@ -540,13 +541,12 @@ void galileo_e1_prs_veml_tracking_cc::update_local_code_prs()
}
uint64_t int_code_phase = static_cast< uint64_t >( std::floor( d_code_phase_chips_prs ) );
double frac_code_phase = std::fmod( d_code_phase_chips_prs, 1.0 );
tcode_chips = frac_code_phase + static_cast< double >( int_code_phase - d_start_index_prs_code );
tcode_chips = d_fractional_code_phase_chips_prs +
static_cast< double >( d_integer_code_phase_chips_prs - d_start_index_prs_code );
//tcode_chips = d_code_phase_chips_prs - static_cast< double >( d_start_index_prs_code );
// Add 1/4 of a cyle here to account for cosine phasing:
tsubcarrier_phase_halfcyles = d_subcarrier_phase_cycles_prs*2.0 + 0.5;
tsubcarrier_phase_halfcyles = d_fractional_code_phase_chips_prs*chips_to_halfcycles + 0.5;
early_late_spc_halfcycles = d_early_late_code_spc_cycles * 2.0;
very_early_late_spc_halfcycles = d_very_early_late_code_spc_chips_prs * chips_to_halfcycles;
@@ -815,13 +815,17 @@ int galileo_e1_prs_veml_tracking_cc::general_work (int noutput_items,gr_vector_i
d_Very_Late_prs );
// Now update the code and carrier phase estimates:
d_code_phase_chips_prs += T*d_code_freq_chips_prs;
//d_code_phase_chips_prs = std::fmod( d_code_phase_chips_prs,
//static_cast<double>( d_prs_code_gen->get_code_length() ) );
if( d_code_phase_chips_prs >= static_cast< double >( d_prs_code_gen->get_code_length() ) )
{
d_code_phase_chips_prs -= static_cast< double >( d_prs_code_gen->get_code_length() );
}
double chips_to_halfcycles_prs = Galileo_E1_A_SUB_CARRIER_RATE_HZ /
Galileo_E1_A_CODE_CHIP_RATE_HZ * 2.0;
double delta_code_phase_prs = T*d_code_freq_chips_prs;
d_fractional_code_phase_chips_prs += delta_code_phase_prs;
d_integer_code_phase_chips_prs += static_cast< int64_t >(
std::floor( d_fractional_code_phase_chips_prs ) );
d_fractional_code_phase_chips_prs = std::fmod(
d_fractional_code_phase_chips_prs, 1.0 );
//DLOG(INFO) << "Propagated PRS code phase: " << std::fixed << std::setprecision( 12 ) << T*d_code_freq_chips_prs;
if( d_use_sa )
@@ -838,14 +842,24 @@ int galileo_e1_prs_veml_tracking_cc::general_work (int noutput_items,gr_vector_i
d_carrier_phase_rad_prs += T*2.0*M_PI*d_carrier_doppler_hz_prs;
double e1b_code_length_prs_chips = Galileo_E1_B_CODE_LENGTH_CHIPS /
Galileo_E1_CODE_CHIP_RATE_HZ * Galileo_E1_A_CODE_CHIP_RATE_HZ;
int64_t e1b_code_length_prs_chips = static_cast< int64_t>(
Galileo_E1_B_CODE_LENGTH_CHIPS /
Galileo_E1_CODE_CHIP_RATE_HZ * Galileo_E1_A_CODE_CHIP_RATE_HZ
);
double rem_code_phase_chips_prs = e1b_code_length_prs_chips -
std::fmod( d_code_phase_chips_prs, e1b_code_length_prs_chips );
if( rem_code_phase_chips_prs > e1b_code_length_prs_chips / 2.0 )
int64_t chips_into_e1b_code_period =
d_integer_code_phase_chips_prs % e1b_code_length_prs_chips;
double rem_code_phase_chips_prs = static_cast< double >(
e1b_code_length_prs_chips - chips_into_e1b_code_period
) - d_fractional_code_phase_chips_prs;
if( rem_code_phase_chips_prs > static_cast< double >(
e1b_code_length_prs_chips / 2 ) )
{
rem_code_phase_chips_prs = ( rem_code_phase_chips_prs - e1b_code_length_prs_chips );
rem_code_phase_chips_prs = ( rem_code_phase_chips_prs -
static_cast<double>(e1b_code_length_prs_chips) );
}
d_rem_code_phase_samples_prs = rem_code_phase_chips_prs * d_fs_in/Galileo_E1_A_CODE_CHIP_RATE_HZ;
@@ -1114,7 +1128,19 @@ int galileo_e1_prs_veml_tracking_cc::general_work (int noutput_items,gr_vector_i
{
double half_cycle_in_chips = 0.5/d_chips_to_cycles_prs;
d_code_phase_chips_prs += half_cycle_in_chips*jump_dir;
d_fractional_code_phase_chips_prs += half_cycle_in_chips*jump_dir;
if( d_fractional_code_phase_chips_prs >= 1.0 )
{
d_fractional_code_phase_chips_prs -= 1.0;
d_integer_code_phase_chips_prs += 1;
}
if( d_fractional_code_phase_chips_prs < 0.0 )
{
d_fractional_code_phase_chips_prs += 1.0;
d_integer_code_phase_chips_prs -= 1;
}
std::stringstream ss("");
@@ -1546,7 +1572,9 @@ int galileo_e1_prs_veml_tracking_cc::general_work (int noutput_items,gr_vector_i
d_dump_file.write(reinterpret_cast<char*>(&subcarrier_error_filt_cycles_prs), sizeof(float));
// SLL commands
d_dump_file.write(reinterpret_cast<char*>(&d_code_phase_chips_prs), sizeof(double));
tmp_double = static_cast< double >( d_integer_code_phase_chips_prs ) +
d_fractional_code_phase_chips_prs;
d_dump_file.write(reinterpret_cast<char*>(&tmp_double), sizeof(double));
d_dump_file.write(reinterpret_cast<char*>(&code_error_chips_veml_prs), sizeof(float));
d_dump_file.write(reinterpret_cast<char*>(&code_error_filt_chips_veml_prs), sizeof(float));
}
@@ -1654,12 +1682,16 @@ void galileo_e1_prs_veml_tracking_cc::start_tracking_prs()
curr_tow -= 604800.0;
}
d_code_phase_chips_prs = std::fmod( curr_tow * Galileo_E1_A_CODE_CHIP_RATE_HZ,
double code_phase_chips_prs = std::fmod( curr_tow * Galileo_E1_A_CODE_CHIP_RATE_HZ,
d_prs_code_gen->get_code_length() );
d_subcarrier_phase_cycles_prs = std::fmod( curr_tow, 1.0/Galileo_E1_A_SUB_CARRIER_RATE_HZ )
* Galileo_E1_A_SUB_CARRIER_RATE_HZ;
d_integer_code_phase_chips_prs = static_cast< int64_t >( std::floor( code_phase_chips_prs ) );
d_fractional_code_phase_chips_prs = std::fmod( code_phase_chips_prs, 1.0 );
d_rem_carr_phase_rad_prs = d_rem_carr_phase_rad - M_PI/2.0;
d_code_freq_chips_prs = d_code_freq_chips * Galileo_E1_A_CODE_CHIP_RATE_HZ /
@@ -1694,7 +1726,7 @@ void galileo_e1_prs_veml_tracking_cc::start_tracking_prs()
LOG(INFO) << "Starting tracking of PRS for satellite " << Gnss_Satellite(systemName[sys], d_acquisition_gnss_synchro->PRN) << " on channel " << d_channel;
DLOG(INFO) << "Starting params: current TOW estimate: " << curr_tow
<< " Code phase " << d_code_phase_chips_prs << " chips."
<< " Code phase " << code_phase_chips_prs << " chips."
<< " Last TOW: " << d_last_tow << " @ " << d_timestamp_last_tow
<< " Correction: " << (curr_tow - d_last_tow);
// enable tracking
@@ -1712,7 +1744,7 @@ void galileo_e1_prs_veml_tracking_cc::start_tracking_prs()
d_mean_subcarrier_error_prs = 0.0;
LOG(INFO) << "PULL-IN Doppler [Hz]=" << d_carrier_doppler_hz_prs
<< " PULL-IN Code Phase [samples]=" << d_code_phase_chips_prs;
<< " PULL-IN Code Phase [samples]=" << code_phase_chips_prs;
}
void galileo_e1_prs_veml_tracking_cc::handle_gnss_message( pmt::pmt_t msg )

4
src/algorithms/tracking/gnuradio_blocks/galileo_e1_prs_veml_tracking_cc.h
View File

@@ -247,7 +247,9 @@ private:
double d_acc_code_phase_secs;
double d_code_freq_chips_prs;
double d_code_phase_chips_prs;
int64_t d_integer_code_phase_chips_prs;
double d_fractional_code_phase_chips_prs;
float d_carrier_doppler_hz_prs;
double d_carrier_phase_rad_prs;
double d_acc_carrier_phase_rad_prs;