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This commit is contained in:
Carles Fernandez
2017-05-11 06:15:06 +02:00
parent 314b80e8ac
commit e82799d687
1 changed files with 236 additions and 256 deletions
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492
src/algorithms/observables/gnuradio_blocks/hybrid_observables_cc.cc
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@@ -41,56 +41,53 @@
#include "Galileo_E1.h" #include "Galileo_E1.h"
#include "GPS_L1_CA.h" #include "GPS_L1_CA.h"
using google::LogMessage; using google::LogMessage;
hybrid_observables_cc_sptr hybrid_observables_cc_sptr hybrid_make_observables_cc(unsigned int nchannels, bool dump, std::string dump_filename, unsigned int deep_history)
hybrid_make_observables_cc(unsigned int nchannels, bool dump, std::string dump_filename, unsigned int deep_history)
{ {
return hybrid_observables_cc_sptr(new hybrid_observables_cc(nchannels, dump, dump_filename, deep_history)); return hybrid_observables_cc_sptr(new hybrid_observables_cc(nchannels, dump, dump_filename, deep_history));
} }
hybrid_observables_cc::hybrid_observables_cc(unsigned int nchannels, bool dump, std::string dump_filename, unsigned int deep_history) : hybrid_observables_cc::hybrid_observables_cc(unsigned int nchannels, bool dump, std::string dump_filename, unsigned int deep_history) :
gr::block("hybrid_observables_cc", gr::io_signature::make(nchannels, nchannels, sizeof(Gnss_Synchro)), gr::block("hybrid_observables_cc", gr::io_signature::make(nchannels, nchannels, sizeof(Gnss_Synchro)),
gr::io_signature::make(nchannels, nchannels, sizeof(Gnss_Synchro))) gr::io_signature::make(nchannels, nchannels, sizeof(Gnss_Synchro)))
{ {
// initialize internal vars // initialize internal vars
d_dump = dump; d_dump = dump;
d_nchannels = nchannels; d_nchannels = nchannels;
d_dump_filename = dump_filename; d_dump_filename = dump_filename;
history_deep = deep_history; history_deep = deep_history;
T_rx_s=0.0; T_rx_s = 0.0;
T_rx_step_s=1e-3;// todo: move to gnss-sdr config T_rx_step_s = 1e-3;// todo: move to gnss-sdr config
for (unsigned int i = 0; i < d_nchannels; i++) for (unsigned int i = 0; i < d_nchannels; i++)
{ {
d_gnss_synchro_history_queue.push_back(std::deque<Gnss_Synchro>()); d_gnss_synchro_history_queue.push_back(std::deque<Gnss_Synchro>());
} }
//todo: this is a gnuradio scheduler hack. //todo: this is a gnuradio scheduler hack.
// Migrate the queues to gnuradio set_history to see if the scheduler can handle // Migrate the queues to gnuradio set_history to see if the scheduler can handle
// the multiple output flow // the multiple output flow
d_max_noutputs=100; d_max_noutputs = 100;
this->set_min_noutput_items(100); this->set_min_noutput_items(100);
// ############# ENABLE DATA FILE LOG ################# // ############# ENABLE DATA FILE LOG #################
if (d_dump == true) if (d_dump == true)
{
if (d_dump_file.is_open() == false)
{ {
try if (d_dump_file.is_open() == false)
{ {
d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit ); try
d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary); {
LOG(INFO) << "Observables dump enabled Log file: " << d_dump_filename.c_str(); d_dump_file.exceptions (std::ifstream::failbit | std::ifstream::badbit );
} d_dump_file.open(d_dump_filename.c_str(), std::ios::out | std::ios::binary);
catch (const std::ifstream::failure & e) LOG(INFO) << "Observables dump enabled Log file: " << d_dump_filename.c_str();
{ }
LOG(WARNING) << "Exception opening observables dump file " << e.what(); catch (const std::ifstream::failure & e)
} {
LOG(WARNING) << "Exception opening observables dump file " << e.what();
}
}
} }
}
} }
@@ -105,25 +102,31 @@ bool Hybrid_pairCompare_gnss_synchro_sample_counter(const std::pair<int,Gnss_Syn
return (a.second.Tracking_sample_counter) < (b.second.Tracking_sample_counter); return (a.second.Tracking_sample_counter) < (b.second.Tracking_sample_counter);
} }
bool Hybrid_valueCompare_gnss_synchro_sample_counter(const Gnss_Synchro& a, unsigned long int b) bool Hybrid_valueCompare_gnss_synchro_sample_counter(const Gnss_Synchro& a, unsigned long int b)
{ {
return (a.Tracking_sample_counter) < (b); return (a.Tracking_sample_counter) < (b);
} }
bool Hybrid_valueCompare_gnss_synchro_receiver_time(const Gnss_Synchro& a, double b) bool Hybrid_valueCompare_gnss_synchro_receiver_time(const Gnss_Synchro& a, double b)
{ {
return (((double)a.Tracking_sample_counter+a.Code_phase_samples)/(double)a.fs) < (b); return (((double)a.Tracking_sample_counter+a.Code_phase_samples)/(double)a.fs) < (b);
} }
bool Hybrid_pairCompare_gnss_synchro_d_TOW(const std::pair<int,Gnss_Synchro>& a, const std::pair<int,Gnss_Synchro>& b) bool Hybrid_pairCompare_gnss_synchro_d_TOW(const std::pair<int,Gnss_Synchro>& a, const std::pair<int,Gnss_Synchro>& b)
{ {
return (a.second.TOW_at_current_symbol_s) < (b.second.TOW_at_current_symbol_s); return (a.second.TOW_at_current_symbol_s) < (b.second.TOW_at_current_symbol_s);
} }
bool Hybrid_valueCompare_gnss_synchro_d_TOW(const Gnss_Synchro& a, double b) bool Hybrid_valueCompare_gnss_synchro_d_TOW(const Gnss_Synchro& a, double b)
{ {
return (a.TOW_at_current_symbol_s) < (b); return (a.TOW_at_current_symbol_s) < (b);
} }
int hybrid_observables_cc::general_work (int noutput_items, int hybrid_observables_cc::general_work (int noutput_items,
gr_vector_int &ninput_items, gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items, gr_vector_const_void_star &input_items,
@@ -131,9 +134,9 @@ int hybrid_observables_cc::general_work (int noutput_items,
{ {
Gnss_Synchro **in = (Gnss_Synchro **) &input_items[0]; // Get the input pointer Gnss_Synchro **in = (Gnss_Synchro **) &input_items[0]; // Get the input pointer
Gnss_Synchro **out = (Gnss_Synchro **) &output_items[0]; // Get the output pointer Gnss_Synchro **out = (Gnss_Synchro **) &output_items[0]; // Get the output pointer
int n_outputs=0; int n_outputs = 0;
int n_consume[d_nchannels]; int n_consume[d_nchannels];
double past_history_s=100e-3; double past_history_s = 100e-3;
Gnss_Synchro current_gnss_synchro[d_nchannels]; Gnss_Synchro current_gnss_synchro[d_nchannels];
@@ -143,255 +146,232 @@ int hybrid_observables_cc::general_work (int noutput_items,
* Record all synchronization data into queues * Record all synchronization data into queues
*/ */
for (unsigned int i = 0; i < d_nchannels; i++) for (unsigned int i = 0; i < d_nchannels; i++)
{
n_consume[i]=ninput_items[i];// full throttle
for (int j=0;j<n_consume[i];j++)
{ {
d_gnss_synchro_history_queue[i].push_back(in[i][j]); n_consume[i] = ninput_items[i];// full throttle
for (int j = 0; j < n_consume[i]; j++)
{
d_gnss_synchro_history_queue[i].push_back(in[i][j]);
}
//std::cout<<"push["<<i<<"] items "<<n_consume[i]
/// <<" latest T_rx: "<<(double)in[i][ninput_items[i]-1].Tracking_sample_counter/(double)in[i][ninput_items[i]-1].fs
// <<" [s] q size: "
// <<d_gnss_synchro_history_queue[i].size()
// <<std::endl;
} }
//std::cout<<"push["<<i<<"] items "<<n_consume[i]
/// <<" latest T_rx: "<<(double)in[i][ninput_items[i]-1].Tracking_sample_counter/(double)in[i][ninput_items[i]-1].fs
// <<" [s] q size: "
// <<d_gnss_synchro_history_queue[i].size()
// <<std::endl;
}
bool channel_history_ok; bool channel_history_ok;
do{ do
channel_history_ok=true;
for (unsigned int i = 0; i < d_nchannels; i++)
{ {
if (d_gnss_synchro_history_queue[i].size()<history_deep) channel_history_ok = true;
{
channel_history_ok=false;
}
}
if (channel_history_ok==true)
{
std::map<int,Gnss_Synchro>::iterator gnss_synchro_map_iter;
std::deque<Gnss_Synchro>::iterator gnss_synchro_deque_iter;
//1. If the RX time is not set, set the Rx time
if (T_rx_s==0)
{
//0. Read a gnss_synchro snapshot from the queue and store it in a map
std::map<int,Gnss_Synchro> gnss_synchro_map;
for (unsigned int i = 0; i < d_nchannels; i++)
{
gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(
d_gnss_synchro_history_queue[i].front().Channel_ID,
d_gnss_synchro_history_queue[i].front()));
}
gnss_synchro_map_iter = min_element(gnss_synchro_map.begin(),
gnss_synchro_map.end(),
Hybrid_pairCompare_gnss_synchro_sample_counter);
T_rx_s = (double)gnss_synchro_map_iter->second.Tracking_sample_counter/(double)gnss_synchro_map_iter->second.fs;
T_rx_s = floor(T_rx_s*1000.0)/1000.0;// truncate to ms
T_rx_s +=past_history_s; //increase T_rx to have a minimum past history to interpolate
}
//2. Realign RX time in all valid channels
std::map<int,Gnss_Synchro> realigned_gnss_synchro_map;//container for the aligned set of observables for the selected T_rx
std::map<int,Gnss_Synchro> adjacent_gnss_synchro_map; //container for the previous observable values to interpolate
//shift channels history to match the reference TOW
for (unsigned int i = 0; i < d_nchannels; i++) for (unsigned int i = 0; i < d_nchannels; i++)
{
gnss_synchro_deque_iter = std::lower_bound(d_gnss_synchro_history_queue[i].begin(),
d_gnss_synchro_history_queue[i].end(),
T_rx_s,
Hybrid_valueCompare_gnss_synchro_receiver_time);
if (gnss_synchro_deque_iter!=d_gnss_synchro_history_queue[i].end())
{ {
if (gnss_synchro_deque_iter->Flag_valid_word==true) if (d_gnss_synchro_history_queue[i].size() < history_deep)
{
double T_rx_channel=(double)gnss_synchro_deque_iter->Tracking_sample_counter/(double)gnss_synchro_deque_iter->fs;
double delta_T_rx_s=T_rx_channel-T_rx_s;
//check that T_rx difference is less than a threshold (the correlation interval)
if (delta_T_rx_s*1000.0<(double)gnss_synchro_deque_iter->correlation_length_ms)
{ {
//record the word structure in a map for pseudorange computation channel_history_ok = false;
//save the previous observable }
int distance=std::distance(d_gnss_synchro_history_queue[i].begin(), gnss_synchro_deque_iter);
if (distance>0) }
{ if (channel_history_ok == true)
double T_rx_channel_prev=(double)d_gnss_synchro_history_queue[i].at(distance-1).Tracking_sample_counter/(double)gnss_synchro_deque_iter->fs; {
double delta_T_rx_s_prev=T_rx_channel_prev-T_rx_s; std::map<int,Gnss_Synchro>::iterator gnss_synchro_map_iter;
if (fabs(delta_T_rx_s_prev)<fabs(delta_T_rx_s)) std::deque<Gnss_Synchro>::iterator gnss_synchro_deque_iter;
//1. If the RX time is not set, set the Rx time
if (T_rx_s == 0)
{
//0. Read a gnss_synchro snapshot from the queue and store it in a map
std::map<int,Gnss_Synchro> gnss_synchro_map;
for (unsigned int i = 0; i < d_nchannels; i++)
{ {
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>( gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(
d_gnss_synchro_history_queue[i].at(distance-1).Channel_ID, d_gnss_synchro_history_queue[i].front().Channel_ID,
d_gnss_synchro_history_queue[i].at(distance-1))); d_gnss_synchro_history_queue[i].front()));
adjacent_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID,
*gnss_synchro_deque_iter));
}else{
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID,
*gnss_synchro_deque_iter));
adjacent_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(
d_gnss_synchro_history_queue[i].at(distance-1).Channel_ID,
d_gnss_synchro_history_queue[i].at(distance-1)));
} }
}else{ gnss_synchro_map_iter = min_element(gnss_synchro_map.begin(),
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID, gnss_synchro_map.end(),
*gnss_synchro_deque_iter)); Hybrid_pairCompare_gnss_synchro_sample_counter);
} T_rx_s = (double)gnss_synchro_map_iter->second.Tracking_sample_counter / (double)gnss_synchro_map_iter->second.fs;
T_rx_s = floor(T_rx_s * 1000.0) / 1000.0; // truncate to ms
}else{ T_rx_s += past_history_s; // increase T_rx to have a minimum past history to interpolate
//std::cout<<"ch["<<i<<"] delta_T_rx:"<<delta_T_rx_s*1000.0<<std::endl;
} }
}
}
}
if(!realigned_gnss_synchro_map.empty())
{
/*
* 2.1 Use CURRENT set of measurements and find the nearest satellite
* common RX time algorithm
*/
// what is the most recent symbol TOW in the current set? -> this will be the reference symbol
gnss_synchro_map_iter = max_element(realigned_gnss_synchro_map.begin(),
realigned_gnss_synchro_map.end(),
Hybrid_pairCompare_gnss_synchro_d_TOW);
double ref_fs_hz=(double)gnss_synchro_map_iter->second.fs;
// compute interpolated TOW value at T_rx_s //2. Realign RX time in all valid channels
int ref_channel_key=gnss_synchro_map_iter->second.Channel_ID; std::map<int,Gnss_Synchro> realigned_gnss_synchro_map; //container for the aligned set of observables for the selected T_rx
Gnss_Synchro adj_obs=adjacent_gnss_synchro_map.at(ref_channel_key); std::map<int,Gnss_Synchro> adjacent_gnss_synchro_map; //container for the previous observable values to interpolate
double ref_adj_T_rx_s=(double)adj_obs.Tracking_sample_counter/ref_fs_hz //shift channels history to match the reference TOW
+adj_obs.Code_phase_samples/ref_fs_hz; for (unsigned int i = 0; i < d_nchannels; i++)
double d_TOW_reference = gnss_synchro_map_iter->second.TOW_at_current_symbol_s;
double d_ref_T_rx_s=(double)gnss_synchro_map_iter->second.Tracking_sample_counter/ref_fs_hz
+gnss_synchro_map_iter->second.Code_phase_samples/ref_fs_hz;
double selected_T_rx_s=T_rx_s;
// two points linear interpolation using adjacent (adj) values: y=y1+(x-x1)*(y2-y1)/(x2-x1)
double ref_TOW_at_T_rx_s = adj_obs.TOW_at_current_symbol_s+(selected_T_rx_s-ref_adj_T_rx_s)
*(d_TOW_reference-adj_obs.TOW_at_current_symbol_s)/(d_ref_T_rx_s-ref_adj_T_rx_s);
//std::cout<<"DELTA T REF:"<<T_rx_s-ref_adj_T_rx_s<<std::endl;
//std::cout<<"ref TOW:"<<d_TOW_reference<<" ref_TOW_at_T_rx_s:"<<ref_TOW_at_T_rx_s<<std::endl;
// std::cout << std::fixed;
// std::cout << std::setprecision(2);
// std::cout<<"d_TOW_reference:"<<d_TOW_reference*1000.0<<std::endl;
//std::cout<<"OBS SV REF SAT: "<<gnss_synchro_map_iter->second.PRN<<std::endl;
// Now compute RX time differences due to the PRN alignment in the correlators
double traveltime_ms;
double pseudorange_m;
double channel_T_rx_s;
double channel_fs_hz;
double channel_TOW_s;
double delta_T_rx_s;
for(gnss_synchro_map_iter = realigned_gnss_synchro_map.begin(); gnss_synchro_map_iter != realigned_gnss_synchro_map.end(); gnss_synchro_map_iter++)
{
channel_fs_hz=(double)gnss_synchro_map_iter->second.fs;
channel_TOW_s=gnss_synchro_map_iter->second.TOW_at_current_symbol_s;
channel_T_rx_s=(double)gnss_synchro_map_iter->second.Tracking_sample_counter/channel_fs_hz
+gnss_synchro_map_iter->second.Code_phase_samples/channel_fs_hz;
// compute interpolated observation values
// two points linear interpolation using adjacent (adj) values: y=y1+(x-x1)*(y2-y1)/(x2-x1)
// TOW at the selected receiver time T_rx_s
int element_key=gnss_synchro_map_iter->second.Channel_ID;
adj_obs=adjacent_gnss_synchro_map.at(element_key);
double adj_T_rx_s=(double)adj_obs.Tracking_sample_counter/channel_fs_hz
+adj_obs.Code_phase_samples/channel_fs_hz;
double channel_TOW_at_T_rx_s = adj_obs.TOW_at_current_symbol_s+(selected_T_rx_s-adj_T_rx_s)
*(channel_TOW_s-adj_obs.TOW_at_current_symbol_s)/(channel_T_rx_s-adj_T_rx_s);
//Doppler and Accumulated carrier phase
double Carrier_phase_lin_rads = adj_obs.Carrier_phase_rads+(selected_T_rx_s-adj_T_rx_s)
*(gnss_synchro_map_iter->second.Carrier_phase_rads-adj_obs.Carrier_phase_rads)/(channel_T_rx_s-adj_T_rx_s);
double Carrier_Doppler_lin_hz = adj_obs.Carrier_Doppler_hz+(selected_T_rx_s-adj_T_rx_s)
*(gnss_synchro_map_iter->second.Carrier_Doppler_hz-adj_obs.Carrier_Doppler_hz)/(channel_T_rx_s-adj_T_rx_s);
//compute the pseudorange (no rx time offset correction)
traveltime_ms = (ref_TOW_at_T_rx_s - channel_TOW_at_T_rx_s) * 1000.0
+ GPS_STARTOFFSET_ms;
//convert to meters
pseudorange_m = traveltime_ms * GPS_C_m_ms; // [m]
// update the pseudorange object
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID] = gnss_synchro_map_iter->second;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Pseudorange_m = pseudorange_m;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Flag_valid_pseudorange = true;
// Save the estimated RX time (no RX clock offset correction yet!)
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].RX_time = ref_TOW_at_T_rx_s + GPS_STARTOFFSET_ms / 1000.0;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Carrier_phase_rads = Carrier_phase_lin_rads;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Carrier_Doppler_hz = Carrier_Doppler_lin_hz;
//debug
//double delta_T_rx_s_previous=((double)adjacent_gnss_synchro_map.at(gnss_synchro_map_iter->second.Channel_ID).Tracking_sample_counter/(double)gnss_synchro_map_iter->second.fs - T_rx_s);
// std::cout<<"["<<gnss_synchro_map_iter->second.PRN<<"] delta_TOW at T_rx: "<<(ref_TOW_at_T_rx_s - channel_TOW_at_T_rx_s)*1000.0
// <<" [ms] delta_TOW_ms: "<<(d_TOW_reference - gnss_synchro_map_iter->second.TOW_at_current_symbol_s) * 1000.0
// <<" Pr: "<<pseudorange_m<<" [m]"
// <<std::endl;
}
//std::cout<<std::endl;
if(d_dump == true)
{
// MULTIPLEXED FILE RECORDING - Record results to file
try
{
double tmp_double;
for (unsigned int i = 0; i < d_nchannels; i++)
{ {
tmp_double = current_gnss_synchro[i].RX_time; gnss_synchro_deque_iter = std::lower_bound(d_gnss_synchro_history_queue[i].begin(),
d_dump_file.write((char*)&tmp_double, sizeof(double)); d_gnss_synchro_history_queue[i].end(),
tmp_double = current_gnss_synchro[i].TOW_at_current_symbol_s; T_rx_s,
d_dump_file.write((char*)&tmp_double, sizeof(double)); Hybrid_valueCompare_gnss_synchro_receiver_time);
tmp_double = current_gnss_synchro[i].Carrier_Doppler_hz; if (gnss_synchro_deque_iter != d_gnss_synchro_history_queue[i].end())
d_dump_file.write((char*)&tmp_double, sizeof(double)); {
tmp_double = current_gnss_synchro[i].Carrier_phase_rads/GPS_TWO_PI; if (gnss_synchro_deque_iter->Flag_valid_word == true)
d_dump_file.write((char*)&tmp_double, sizeof(double)); {
tmp_double = current_gnss_synchro[i].Pseudorange_m; double T_rx_channel = (double)gnss_synchro_deque_iter->Tracking_sample_counter / (double)gnss_synchro_deque_iter->fs;
d_dump_file.write((char*)&tmp_double, sizeof(double)); double delta_T_rx_s = T_rx_channel - T_rx_s;
tmp_double = current_gnss_synchro[i].PRN;
d_dump_file.write((char*)&tmp_double, sizeof(double)); //check that T_rx difference is less than a threshold (the correlation interval)
if (delta_T_rx_s * 1000.0 < (double)gnss_synchro_deque_iter->correlation_length_ms)
{
//record the word structure in a map for pseudorange computation
//save the previous observable
int distance = std::distance(d_gnss_synchro_history_queue[i].begin(), gnss_synchro_deque_iter);
if (distance > 0)
{
double T_rx_channel_prev = (double)d_gnss_synchro_history_queue[i].at(distance - 1).Tracking_sample_counter / (double)gnss_synchro_deque_iter->fs;
double delta_T_rx_s_prev = T_rx_channel_prev - T_rx_s;
if (fabs(delta_T_rx_s_prev) < fabs(delta_T_rx_s))
{
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(
d_gnss_synchro_history_queue[i].at(distance-1).Channel_ID,
d_gnss_synchro_history_queue[i].at(distance-1)));
adjacent_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID, *gnss_synchro_deque_iter));
}
else
{
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID, *gnss_synchro_deque_iter));
adjacent_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(
d_gnss_synchro_history_queue[i].at(distance-1).Channel_ID,
d_gnss_synchro_history_queue[i].at(distance-1)));
}
}
else
{
realigned_gnss_synchro_map.insert(std::pair<int, Gnss_Synchro>(gnss_synchro_deque_iter->Channel_ID, *gnss_synchro_deque_iter));
}
}
else
{
//std::cout<<"ch["<<i<<"] delta_T_rx:"<<delta_T_rx_s*1000.0<<std::endl;
}
}
}
} }
}
catch (const std::ifstream::failure& e)
{
LOG(WARNING) << "Exception writing observables dump file " << e.what();
}
}
for (unsigned int i = 0; i < d_nchannels; i++) if(!realigned_gnss_synchro_map.empty())
{ {
out[i][n_outputs] = current_gnss_synchro[i]; /*
} * 2.1 Use CURRENT set of measurements and find the nearest satellite
* common RX time algorithm
*/
// what is the most recent symbol TOW in the current set? -> this will be the reference symbol
gnss_synchro_map_iter = max_element(realigned_gnss_synchro_map.begin(),
realigned_gnss_synchro_map.end(),
Hybrid_pairCompare_gnss_synchro_d_TOW);
double ref_fs_hz = (double)gnss_synchro_map_iter->second.fs;
n_outputs++; // compute interpolated TOW value at T_rx_s
} int ref_channel_key = gnss_synchro_map_iter->second.Channel_ID;
Gnss_Synchro adj_obs = adjacent_gnss_synchro_map.at(ref_channel_key);
double ref_adj_T_rx_s = (double)adj_obs.Tracking_sample_counter / ref_fs_hz + adj_obs.Code_phase_samples / ref_fs_hz;
//Move RX time double d_TOW_reference = gnss_synchro_map_iter->second.TOW_at_current_symbol_s;
T_rx_s=T_rx_s+T_rx_step_s; double d_ref_T_rx_s = (double)gnss_synchro_map_iter->second.Tracking_sample_counter / ref_fs_hz + gnss_synchro_map_iter->second.Code_phase_samples / ref_fs_hz;
//pop old elements from queue
for (unsigned int i=0; i<d_nchannels;i++) double selected_T_rx_s = T_rx_s;
{ // two points linear interpolation using adjacent (adj) values: y=y1+(x-x1)*(y2-y1)/(x2-x1)
while (d_gnss_synchro_history_queue[i].front().Tracking_sample_counter/(double)d_gnss_synchro_history_queue[i].front().fs<(T_rx_s-past_history_s)) double ref_TOW_at_T_rx_s = adj_obs.TOW_at_current_symbol_s + (selected_T_rx_s - ref_adj_T_rx_s)
{ * (d_TOW_reference - adj_obs.TOW_at_current_symbol_s) / (d_ref_T_rx_s - ref_adj_T_rx_s);
d_gnss_synchro_history_queue[i].pop_front();
// Now compute RX time differences due to the PRN alignment in the correlators
double traveltime_ms;
double pseudorange_m;
double channel_T_rx_s;
double channel_fs_hz;
double channel_TOW_s;
double delta_T_rx_s;
for(gnss_synchro_map_iter = realigned_gnss_synchro_map.begin(); gnss_synchro_map_iter != realigned_gnss_synchro_map.end(); gnss_synchro_map_iter++)
{
channel_fs_hz = (double)gnss_synchro_map_iter->second.fs;
channel_TOW_s = gnss_synchro_map_iter->second.TOW_at_current_symbol_s;
channel_T_rx_s = (double)gnss_synchro_map_iter->second.Tracking_sample_counter / channel_fs_hz + gnss_synchro_map_iter->second.Code_phase_samples / channel_fs_hz;
// compute interpolated observation values
// two points linear interpolation using adjacent (adj) values: y=y1+(x-x1)*(y2-y1)/(x2-x1)
// TOW at the selected receiver time T_rx_s
int element_key = gnss_synchro_map_iter->second.Channel_ID;
adj_obs = adjacent_gnss_synchro_map.at(element_key);
double adj_T_rx_s = (double)adj_obs.Tracking_sample_counter / channel_fs_hz + adj_obs.Code_phase_samples / channel_fs_hz;
double channel_TOW_at_T_rx_s = adj_obs.TOW_at_current_symbol_s + (selected_T_rx_s - adj_T_rx_s) * (channel_TOW_s - adj_obs.TOW_at_current_symbol_s) / (channel_T_rx_s - adj_T_rx_s);
//Doppler and Accumulated carrier phase
double Carrier_phase_lin_rads = adj_obs.Carrier_phase_rads + (selected_T_rx_s - adj_T_rx_s) * (gnss_synchro_map_iter->second.Carrier_phase_rads - adj_obs.Carrier_phase_rads) / (channel_T_rx_s - adj_T_rx_s);
double Carrier_Doppler_lin_hz = adj_obs.Carrier_Doppler_hz + (selected_T_rx_s - adj_T_rx_s) * (gnss_synchro_map_iter->second.Carrier_Doppler_hz - adj_obs.Carrier_Doppler_hz) / (channel_T_rx_s - adj_T_rx_s);
//compute the pseudorange (no rx time offset correction)
traveltime_ms = (ref_TOW_at_T_rx_s - channel_TOW_at_T_rx_s) * 1000.0 + GPS_STARTOFFSET_ms;
//convert to meters
pseudorange_m = traveltime_ms * GPS_C_m_ms; // [m]
// update the pseudorange object
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID] = gnss_synchro_map_iter->second;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Pseudorange_m = pseudorange_m;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Flag_valid_pseudorange = true;
// Save the estimated RX time (no RX clock offset correction yet!)
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].RX_time = ref_TOW_at_T_rx_s + GPS_STARTOFFSET_ms / 1000.0;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Carrier_phase_rads = Carrier_phase_lin_rads;
current_gnss_synchro[gnss_synchro_map_iter->second.Channel_ID].Carrier_Doppler_hz = Carrier_Doppler_lin_hz;
}
if(d_dump == true)
{
// MULTIPLEXED FILE RECORDING - Record results to file
try
{
double tmp_double;
for (unsigned int i = 0; i < d_nchannels; i++)
{
tmp_double = current_gnss_synchro[i].RX_time;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].TOW_at_current_symbol_s;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].Carrier_Doppler_hz;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].Carrier_phase_rads/GPS_TWO_PI;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].Pseudorange_m;
d_dump_file.write((char*)&tmp_double, sizeof(double));
tmp_double = current_gnss_synchro[i].PRN;
d_dump_file.write((char*)&tmp_double, sizeof(double));
}
}
catch (const std::ifstream::failure& e)
{
LOG(WARNING) << "Exception writing observables dump file " << e.what();
}
}
for (unsigned int i = 0; i < d_nchannels; i++)
{
out[i][n_outputs] = current_gnss_synchro[i];
}
n_outputs++;
}
//Move RX time
T_rx_s = T_rx_s + T_rx_step_s;
//pop old elements from queue
for (unsigned int i = 0; i < d_nchannels; i++)
{
while (d_gnss_synchro_history_queue[i].front().Tracking_sample_counter / (double)d_gnss_synchro_history_queue[i].front().fs < (T_rx_s - past_history_s))
{
d_gnss_synchro_history_queue[i].pop_front();
}
}
} }
} }while(channel_history_ok == true && d_max_noutputs>n_outputs);
}
}while(channel_history_ok==true && d_max_noutputs>n_outputs);
//Multi-rate consume! //Multi-rate consume!
for (unsigned int i=0; i<d_nchannels;i++) for (unsigned int i = 0; i < d_nchannels; i++)
{ {
consume(i,n_consume[i]); //which input, how many items consume(i, n_consume[i]); //which input, how many items
} }
//std::cout<<"OBS noutput_items: "<<noutput_items<<std::endl;
return n_outputs; return n_outputs;
} }