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Closed the loop of PRS Double Estimator tracking

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This commit is contained in:
Cillian O'Driscoll
2015-11-11 12:14:41 +00:00
parent b2838cb688
commit d3511a0091
1 changed files with 89 additions and 33 deletions
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122
src/algorithms/tracking/gnuradio_blocks/galileo_e1_prs_de_tracking_cc.cc
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@@ -134,6 +134,9 @@ galileo_e1_prs_de_tracking_cc::galileo_e1_prs_de_tracking_cc(
d_aid_subcarrier_with_carrier = aid_subcarrier_with_carrier;
d_aid_code_with_subcarrier = aid_code_with_subcarrier;
d_code_loop_filter_prs = Tracking_loop_filter(Galileo_E1_CODE_PERIOD, dll_bw_hz, 1, false);
d_subcarrier_loop_filter_prs = Tracking_loop_filter(Galileo_E1_CODE_PERIOD, sll_bw_hz, 1, false);
d_carrier_loop_filter_prs = Tracking_loop_filter(Galileo_E1_CODE_PERIOD, pll_bw_hz, 3, false);
// Initialize tracking ==========================================
@@ -243,6 +246,7 @@ galileo_e1_prs_de_tracking_cc::galileo_e1_prs_de_tracking_cc(
d_acq_code_phase_samples = 0.0;
d_acq_carrier_doppler_hz = 0.0;
d_carrier_doppler_hz = 0.0;
d_carrier_doppler_hz_prs = 0.0;
d_acc_carrier_phase_rad = 0.0;
d_acc_code_phase_secs = 0.0;
}
@@ -638,6 +642,10 @@ int galileo_e1_prs_de_tracking_cc::general_work (int noutput_items,gr_vector_int
d_rem_code_phase_samples = rem_code_phase_chips * d_fs_in/Galileo_E1_CODE_CHIP_RATE_HZ;
//remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * T;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
// PRS tracking
if( d_prs_tracking_enabled ){
// Generate local code and carrier replicas (using \hat{f}_d(k-1))
@@ -688,6 +696,9 @@ int galileo_e1_prs_de_tracking_cc::general_work (int noutput_items,gr_vector_int
d_rem_subcarrier_phase_samples_prs = rem_subcarrier_phase_cycles_prs*
static_cast<double>(d_fs_in)/Galileo_E1_A_SUB_CARRIER_RATE_HZ;
d_rem_carr_phase_rad_prs = d_rem_carr_phase_rad_prs + GPS_TWO_PI * d_carrier_doppler_hz_prs * T;
d_rem_carr_phase_rad_prs = fmod(d_rem_carr_phase_rad_prs, GPS_TWO_PI);
}
// check for samples consistency (this should be done before in the receiver / here only if the source is a file)
@@ -738,9 +749,6 @@ int galileo_e1_prs_de_tracking_cc::general_work (int noutput_items,gr_vector_int
}
//carrier phase accumulator for (K) Doppler estimation
d_acc_carrier_phase_rad = d_acc_carrier_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * Galileo_E1_CODE_PERIOD;
//remnant carrier phase to prevent overflow in the code NCO
d_rem_carr_phase_rad = d_rem_carr_phase_rad + GPS_TWO_PI * d_carrier_doppler_hz * Galileo_E1_CODE_PERIOD;
d_rem_carr_phase_rad = fmod(d_rem_carr_phase_rad, GPS_TWO_PI);
// ################## SLL ##########################################################
// SLL discriminator
@@ -791,40 +799,81 @@ int galileo_e1_prs_de_tracking_cc::general_work (int noutput_items,gr_vector_int
d_acc_code_phase_secs = d_acc_code_phase_secs + code_error_filt_secs;
// ################## PRS ##########################################################
// ################## PLL ##########################################################
// PLL discriminator
carr_error_hz_prs = pll_cloop_two_quadrant_atan(*d_Prompt_Subcarrier_Prompt_Code_prs) / static_cast<float>(GPS_TWO_PI);
if( d_prs_tracking_enabled )
{
// ################## PLL ##########################################################
// PLL discriminator
carr_error_hz_prs = pll_cloop_two_quadrant_atan(*d_Prompt_Subcarrier_Prompt_Code_prs) / static_cast<float>(GPS_TWO_PI);
// FOR NOW : Use E1b value
d_carrier_doppler_hz_prs = d_carrier_doppler_hz;
// Carrier discriminator filter
carr_error_filt_hz_prs = d_carrier_loop_filter_prs.apply(carr_error_hz_prs);
// New carrier Doppler frequency estimation
d_carrier_doppler_hz_prs = carr_error_filt_hz_prs;
// ################## SLL ##########################################################
// SLL discriminator
subcarrier_error_cycles_prs = dll_nc_e_minus_l_normalized(
*d_Prompt_Code_Early_Subcarrier_prs,
*d_Prompt_Code_Late_Subcarrier_prs); //[chips/Ti]
// normalise the SLL discriminator by the slope of the
// BOC(1,1) at the origin:
corr_slope = 2.0;
subcarrier_error_cycles_prs *= ( 1 - corr_slope*d_early_late_subcarrier_spc_cycles) / corr_slope;
float subcarrier_doppler_cycles_prs = ((d_carrier_doppler_hz *
Galileo_E1_A_SUB_CARRIER_RATE_HZ) / Galileo_E1_FREQ_HZ);
// For now use the E1b values
d_subcarrier_freq_cycles_prs = d_subcarrier_freq_cycles
* Galileo_E1_A_SUB_CARRIER_RATE_HZ / Galileo_E1_SUB_CARRIER_A_RATE_HZ;
// New subcarrier Doppler frequency estimation: carrier
// aiding of the subcarrier:
if( d_aid_subcarrier_with_carrier )
{
d_subcarrier_freq_cycles_prs = Galileo_E1_A_SUB_CARRIER_RATE_HZ + subcarrier_doppler_cycles_prs;
}
else
{
d_subcarrier_freq_cycles_prs = Galileo_E1_A_SUB_CARRIER_RATE_HZ;
}
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips_prs = dll_nc_e_minus_l_normalized(
*d_Prompt_Subcarrier_Early_Code_prs,
*d_Prompt_Subcarrier_Late_Code_prs); //[chips/Ti]
//Normalise the code phase error:
corr_slope = 1.0;
code_error_chips_prs *= ( 1 - corr_slope*d_early_late_code_spc_chips) / corr_slope;
// ################## SLL ##########################################################
// SLL discriminator
subcarrier_error_cycles_prs = dll_nc_e_minus_l_normalized(
*d_Prompt_Code_Early_Subcarrier_prs,
*d_Prompt_Code_Late_Subcarrier_prs); //[chips/Ti]
// normalise the SLL discriminator by the slope of the
// BOC(1,1) at the origin:
corr_slope = 2.0;
subcarrier_error_cycles_prs *= ( 1 - corr_slope*d_early_late_subcarrier_spc_cycles) / corr_slope;
// For now use the E1 values:
d_code_freq_chips_prs = d_code_freq_chips * Galileo_E1_A_CODE_CHIP_RATE_HZ /
Galileo_E1_CODE_CHIP_RATE_HZ;
// Subcarrier discriminator filter
subcarrier_error_filt_cycles_prs = d_subcarrier_loop_filter_prs.apply(subcarrier_error_cycles_prs); //[chips/second]
// For now use the E1b values
d_subcarrier_freq_cycles_prs += subcarrier_error_filt_cycles_prs;
// ################## DLL ##########################################################
// DLL discriminator
code_error_chips_prs = dll_nc_e_minus_l_normalized(
*d_Prompt_Subcarrier_Early_Code_prs,
*d_Prompt_Subcarrier_Late_Code_prs); //[chips/Ti]
//Normalise the code phase error:
corr_slope = 1.0;
code_error_chips_prs *= ( 1 - corr_slope*d_early_late_code_spc_chips) / corr_slope;
// Code discriminator filter
code_error_filt_chips_prs = d_code_loop_filter_prs.apply(code_error_chips_prs); //[chips/second]
// Aiding the code tracking with the subcarrier:
if( d_aid_code_with_subcarrier )
{
d_code_freq_chips_prs = d_subcarrier_freq_cycles_prs *
Galileo_E1_A_CODE_CHIP_RATE_HZ/Galileo_E1_A_SUB_CARRIER_RATE_HZ;
}
else if( d_aid_subcarrier_with_carrier )
{
float code_doppler_chips_prs = ((d_carrier_doppler_hz_prs *
Galileo_E1_A_CODE_CHIP_RATE_HZ) / Galileo_E1_FREQ_HZ);
d_code_freq_chips_prs = Galileo_E1_A_CODE_CHIP_RATE_HZ + code_doppler_chips;
}
else
{
d_code_freq_chips_prs = Galileo_E1_A_CODE_CHIP_RATE_HZ;
}
// For now use the E1 values:
d_code_freq_chips_prs += code_error_filt_chips_prs;
}
// ################## CARRIER AND CODE NCO BUFFER ALIGNEMENT #######################
// keep alignment parameters for the next input buffer
@@ -1150,7 +1199,7 @@ void galileo_e1_prs_de_tracking_cc::start_tracking_prs()
d_subcarrier_phase_halfcycles_prs = std::fmod( curr_tow,
1.0/Galileo_E1_A_SUB_CARRIER_RATE_HZ ) * 2.0 * Galileo_E1_A_SUB_CARRIER_RATE_HZ;
d_rem_carr_phase_rad_prs = d_rem_carr_phase_rad + M_PI/2.0;
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 /
Galileo_E1_CODE_CHIP_RATE_HZ;
@@ -1162,7 +1211,14 @@ void galileo_e1_prs_de_tracking_cc::start_tracking_prs()
// Initialise the filters:
// TODO:
// DLL/PLL filter initialization
d_carrier_loop_filter_prs.initialize(d_carrier_doppler_hz_prs); // initialize the carrier filter
d_subcarrier_loop_filter_prs.initialize(
d_aid_subcarrier_with_carrier ? 0.0 : d_subcarrier_freq_cycles_prs); // initialize the subcarrier filter
d_code_loop_filter_prs.initialize(
( d_aid_subcarrier_with_carrier || d_aid_code_with_subcarrier ) ?
0.0 : d_code_freq_chips_prs); // initialize the code filter
std::string sys_ = &d_acquisition_gnss_synchro->System;