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Improving unified tracking. Added Doppler frequency correction for false PLL lock

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This commit is contained in:
Javier Arribas
2019-06-14 12:52:46 +02:00
parent afc2a98089
commit 88f78a107c
13 changed files with 43 additions and 25 deletions
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25
src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.cc
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@@ -99,6 +99,7 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl
this->set_msg_handler(pmt::mp("telemetry_to_trk"), boost::bind(&dll_pll_veml_tracking::msg_handler_telemetry_to_trk, this, _1));
// initialize internal vars
d_dll_filt_history.set_capacity(2000);
d_veml = false;
d_cloop = true;
d_pull_in_transitory = true;
@@ -525,6 +526,7 @@ dll_pll_veml_tracking::dll_pll_veml_tracking(const Dll_Pll_Conf &conf_) : gr::bl
d_dump = false;
}
}
d_corrected_doppler = false;
}
@@ -553,7 +555,7 @@ void dll_pll_veml_tracking::msg_handler_telemetry_to_trk(const pmt::pmt_t &msg)
{
DLOG(INFO) << "Telemetry fault received in ch " << this->d_channel;
gr::thread::scoped_lock lock(d_setlock);
d_carrier_lock_fail_counter = 10000; //force loss-of-lock condition
d_carrier_lock_fail_counter = 100000; //force loss-of-lock condition
break;
}
default:
@@ -771,6 +773,7 @@ void dll_pll_veml_tracking::start_tracking()
d_cloop = true;
d_pull_in_transitory = true;
d_Prompt_circular_buffer.clear();
d_corrected_doppler = false;
}
@@ -1016,9 +1019,25 @@ void dll_pll_veml_tracking::run_dll_pll()
}
// Code discriminator filter
d_code_error_filt_chips = d_code_loop_filter.apply(d_code_error_chips); // [chips/second]
// New code Doppler frequency estimation
d_code_freq_chips = (1.0 + (d_carrier_doppler_hz / d_signal_carrier_freq)) * d_code_chip_rate - d_code_error_filt_chips;
// Experimental: detect Carrier Doppler vs. Code Doppler incoherence and correct the Carrier Doppler
if (d_pull_in_transitory == false and d_corrected_doppler == false)
{
d_dll_filt_history.push_back(static_cast<float>(d_code_error_filt_chips));
if (d_dll_filt_history.full())
{
float avg_code_error_chips_s = std::accumulate(d_dll_filt_history.begin(), d_dll_filt_history.end(), 0) / static_cast<float>(d_dll_filt_history.capacity());
if (fabs(avg_code_error_chips_s) > 1.0)
{
float carrier_doppler_error_hz = static_cast<float>(d_signal_carrier_freq) * avg_code_error_chips_s / static_cast<float>(d_code_chip_rate);
LOG(INFO) << "Detected and corrected carrier doppler error: " << carrier_doppler_error_hz << " [Hz] on sat " << Gnss_Satellite(systemName, d_acquisition_gnss_synchro->PRN);
d_carrier_loop_filter.initialize(d_carrier_doppler_hz - carrier_doppler_error_hz);
d_corrected_doppler = true;
}
}
}
}
@@ -1641,7 +1660,7 @@ int dll_pll_veml_tracking::general_work(int noutput_items __attribute__((unused)
d_cn0_smoother.reset();
d_carrier_lock_test_smoother.reset();
DLOG(INFO) << "Number of samples between Acquisition and Tracking = " << acq_trk_diff_samples << " ( " << acq_trk_diff_seconds << " s)";
LOG(INFO) << "Number of samples between Acquisition and Tracking = " << acq_trk_diff_samples << " ( " << acq_trk_diff_seconds << " s)";
DLOG(INFO) << "PULL-IN Doppler [Hz] = " << d_carrier_doppler_hz
<< ". PULL-IN Code Phase [samples] = " << d_acq_code_phase_samples;

3
src/algorithms/tracking/gnuradio_blocks/dll_pll_veml_tracking.h
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@@ -113,6 +113,8 @@ private:
int32_t d_preamble_length_symbols;
boost::circular_buffer<float> d_symbol_history;
// dll filter buffer
boost::circular_buffer<float> d_dll_filt_history;
// tracking state machine
int32_t d_state;
@@ -170,6 +172,7 @@ private:
// tracking vars
bool d_pull_in_transitory;
bool d_corrected_doppler;
double d_current_correlation_time_s;
double d_carr_phase_error_hz;
double d_carr_freq_error_hz;