GNSS-SDR 0.0.21
An Open Source GNSS Software Defined Receiver
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gps_l1_ca_gaussian_tracking_cc.h
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1/*!
2 * \file gps_l1_ca_gaussian_tracking_cc.h
3 * \brief Interface of a processing block of a DLL + Kalman carrier
4 * tracking loop for GPS L1 C/A signals
5 * \author Javier Arribas, 2018. jarribas(at)cttc.es
6 * \author Jordi Vila-Valls 2018. jvila(at)cttc.es
7 * \author Carles Fernandez-Prades 2018. cfernandez(at)cttc.es
8 *
9 * Reference:
10 * J. Vila-Valls, P. Closas, M. Navarro and C. Fernandez-Prades,
11 * "Are PLLs Dead? A Tutorial on Kalman Filter-based Techniques for Digital
12 * Carrier Synchronization", IEEE Aerospace and Electronic Systems Magazine,
13 * Vol. 32, No. 7, pp. 28–45, July 2017. DOI: 10.1109/MAES.2017.150260
14 *
15 * -----------------------------------------------------------------------------
16 *
17 * GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
18 * This file is part of GNSS-SDR.
19 *
20 * Copyright (C) 2010-2020 (see AUTHORS file for a list of contributors)
21 * SPDX-License-Identifier: GPL-3.0-or-later
22 *
23 * -----------------------------------------------------------------------------
24 */
25
26#ifndef GNSS_SDR_GPS_L1_CA_GAUSSIAN_TRACKING_CC_H
27#define GNSS_SDR_GPS_L1_CA_GAUSSIAN_TRACKING_CC_H
28
29#if ARMA_NO_BOUND_CHECKING
30#define ARMA_NO_DEBUG 1
31#endif
32
33#include "bayesian_estimation.h"
34#include "cpu_multicorrelator_real_codes.h"
35#include "gnss_block_interface.h"
36#include "gnss_synchro.h"
37#include "tracking_2nd_DLL_filter.h"
38#include "tracking_2nd_PLL_filter.h"
39#include <armadillo>
40#include <gnuradio/block.h>
41#include <volk_gnsssdr/volk_gnsssdr_alloc.h> // for volk_gnsssdr::vector
42#include <fstream>
43#include <map>
44#include <string>
45
46/** \addtogroup Tracking
47 * \{ */
48/** \addtogroup Tracking_gnuradio_blocks
49 * \{ */
50
51
52class Gps_L1_Ca_Gaussian_Tracking_cc;
53
54using gps_l1_ca_gaussian_tracking_cc_sptr = gnss_shared_ptr<Gps_L1_Ca_Gaussian_Tracking_cc>;
55
56gps_l1_ca_gaussian_tracking_cc_sptr
57gps_l1_ca_gaussian_make_tracking_cc(uint32_t order,
58 int64_t fs_in,
59 uint32_t vector_length,
60 bool dump,
61 const std::string& dump_filename,
62 float dll_bw_hz,
63 float early_late_space_chips,
64 bool bce_run,
65 uint32_t bce_ptrans,
66 uint32_t bce_strans,
67 int32_t bce_nu,
68 int32_t bce_kappa);
69
70
71/*!
72 * \brief This class implements a DLL + PLL tracking loop block
73 */
74class Gps_L1_Ca_Gaussian_Tracking_cc : public gr::block
75{
76public:
77 ~Gps_L1_Ca_Gaussian_Tracking_cc();
78
79 void set_channel(uint32_t channel);
80 void set_gnss_synchro(Gnss_Synchro* p_gnss_synchro);
81 void start_tracking();
82
83 int general_work(int noutput_items, gr_vector_int& ninput_items,
84 gr_vector_const_void_star& input_items, gr_vector_void_star& output_items);
85
86 void forecast(int noutput_items, gr_vector_int& ninput_items_required);
87
88private:
89 friend gps_l1_ca_gaussian_tracking_cc_sptr
90 gps_l1_ca_gaussian_make_tracking_cc(uint32_t order,
91 int64_t fs_in,
92 uint32_t vector_length,
93 bool dump,
94 const std::string& dump_filename,
95 float dll_bw_hz,
96 float early_late_space_chips,
97 bool bce_run,
98 uint32_t bce_ptrans,
99 uint32_t bce_strans,
100 int32_t bce_nu,
101 int32_t bce_kappa);
102
103 Gps_L1_Ca_Gaussian_Tracking_cc(uint32_t order,
104 int64_t fs_in,
105 uint32_t vector_length,
106 bool dump,
107 const std::string& dump_filename,
108 float dll_bw_hz,
109 float early_late_space_chips,
110 bool bce_run,
111 uint32_t bce_ptrans,
112 uint32_t bce_strans,
113 int32_t bce_nu,
114 int32_t bce_kappa);
115
116 int32_t save_matfile();
117
118 // tracking configuration vars
119 uint32_t d_order;
120 uint32_t d_vector_length;
121 bool d_dump;
122
123 Gnss_Synchro* d_acquisition_gnss_synchro;
124 uint32_t d_channel;
125
126 int64_t d_fs_in;
127
128 double d_early_late_spc_chips;
129
130 // remaining code phase and carrier phase between tracking loops
131 double d_rem_code_phase_samples;
132 double d_rem_code_phase_chips;
133 float d_rem_carr_phase_rad;
134
135 // Kalman filter variables
136 arma::mat kf_P_x_ini; // initial state error covariance matrix
137 arma::mat kf_P_x; // state error covariance matrix
138 arma::mat kf_P_x_pre; // Predicted state error covariance matrix
139 arma::mat kf_P_y; // innovation covariance matrix
140
141 arma::mat kf_F; // state transition matrix
142 arma::mat kf_H; // system matrix
143 arma::mat kf_R; // measurement error covariance matrix
144 arma::mat kf_Q; // system error covariance matrix
145
146 arma::colvec kf_x; // state vector
147 arma::colvec kf_x_pre; // predicted state vector
148 arma::colvec kf_y; // measurement vector
149 arma::mat kf_K; // Kalman gain matrix
150
151 // Gaussian estimator
152 Bayesian_estimator bayes_estimator;
153 arma::mat kf_R_est; // measurement error covariance
154 uint32_t bayes_ptrans;
155 uint32_t bayes_strans;
156 int32_t bayes_nu;
157 int32_t bayes_kappa;
158
159 bool bayes_run;
160 uint32_t kf_iter;
161
162 // PLL and DLL filter library
163 Tracking_2nd_DLL_filter d_code_loop_filter;
164 // Tracking_2nd_PLL_filter d_carrier_loop_filter;
165
166 // acquisition
167 double d_acq_carrier_doppler_step_hz{};
168 double d_acq_code_phase_samples;
169 double d_acq_carrier_doppler_hz;
170 // correlator
171 int32_t d_n_correlator_taps;
172 volk_gnsssdr::vector<float> d_ca_code;
173 volk_gnsssdr::vector<float> d_local_code_shift_chips;
174 volk_gnsssdr::vector<gr_complex> d_correlator_outs;
175 Cpu_Multicorrelator_Real_Codes multicorrelator_cpu;
176
177 // tracking vars
178 double d_code_freq_chips;
179 double d_code_phase_step_chips;
180 double d_code_phase_rate_step_chips;
181 double d_carrier_doppler_hz;
182 double d_carrier_dopplerrate_hz2;
183 double d_carrier_phase_step_rad;
184 double d_acc_carrier_phase_rad;
185 double d_carr_phase_error_rad{};
186 double d_carr_phase_sigma2;
187 double d_code_phase_samples;
188 double code_error_chips;
189 double code_error_filt_chips;
190
191 // PRN period in samples
192 int32_t d_current_prn_length_samples;
193
194 // processing samples counters
195 uint64_t d_sample_counter;
196 uint64_t d_acq_sample_stamp;
197
198 // CN0 estimation and lock detector
199 int32_t d_cn0_estimation_counter;
200 volk_gnsssdr::vector<gr_complex> d_Prompt_buffer;
201 double d_carrier_lock_test;
202 double d_CN0_SNV_dB_Hz;
203 double d_carrier_lock_threshold;
204 int32_t d_carrier_lock_fail_counter;
205
206 // control vars
207 bool d_enable_tracking;
208 bool d_pull_in;
209
210 // file dump
211 std::string d_dump_filename;
212 std::ofstream d_dump_file;
213
214 std::map<std::string, std::string> systemName;
215 std::string sys;
216};
217
218
219/** \} */
220/** \} */
221#endif // GNSS_SDR_GPS_L1_CA_GAUSSIAN_TRACKING_CC_H
bayesian_estimation.h
Interface of a library with Bayesian noise statistic estimation.
Bayesian_estimator
Bayesian_estimator is an estimator of noise characteristics (i.e. mean, covariance).
Definition bayesian_estimation.h:61
Cpu_Multicorrelator_Real_Codes
Class that implements carrier wipe-off and correlators.
Definition cpu_multicorrelator_real_codes.h:38
Gnss_Synchro
This is the class that contains the information that is shared by the processing blocks.
Definition gnss_synchro.h:39
Gps_L1_Ca_Gaussian_Tracking_cc
This class implements a DLL + PLL tracking loop block.
Definition gps_l1_ca_gaussian_tracking_cc.h:75
Tracking_2nd_DLL_filter
This class implements a 2nd order DLL filter for code tracking loop.
Definition tracking_2nd_DLL_filter.h:41
cpu_multicorrelator_real_codes.h
Highly optimized CPU vector multiTAP correlator class using real-valued local codes.
gnss_block_interface.h
This interface represents a GNSS block.
gnss_synchro.h
Interface of the Gnss_Synchro class.
tracking_2nd_DLL_filter.h
Interface of a 2nd order DLL filter for code tracking loop.
tracking_2nd_PLL_filter.h
Interface of a 2nd order PLL filter for carrier tracking loop.
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