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[WIP] Fixing threshold setting in pcps_acquisition

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This commit is contained in:
Cillian O'Driscoll 2019-11-04 17:15:53 +00:00
parent 695f3a9456
commit 75c57e90e5
2 changed files with 56 additions and 28 deletions
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83
src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc
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@ -48,6 +48,7 @@
#else #else
#include <boost/filesystem/path.hpp> #include <boost/filesystem/path.hpp>
#endif #endif
#include <boost/math/special_functions/gamma.hpp>
#include <gnuradio/io_signature.h> #include <gnuradio/io_signature.h>
#include <matio.h> #include <matio.h>
#include <pmt/pmt.h> // for from_long #include <pmt/pmt.h> // for from_long
@ -105,7 +106,7 @@ pcps_acquisition::pcps_acquisition(const Acq_Conf& conf_) : gr::block("pcps_acqu
d_input_power = 0.0; d_input_power = 0.0;
d_num_doppler_bins = 0U; d_num_doppler_bins = 0U;
d_threshold = 0.0; d_threshold = 0.0;
d_doppler_step = 0U; d_doppler_step = acq_parameters.doppler_step;
d_doppler_center = 0U; d_doppler_center = 0U;
d_doppler_center_step_two = 0.0; d_doppler_center_step_two = 0.0;
d_test_statistics = 0.0; d_test_statistics = 0.0;
@ -129,11 +130,11 @@ pcps_acquisition::pcps_acquisition(const Acq_Conf& conf_) : gr::block("pcps_acqu
// //
// We can avoid this by doing linear correlation, effectively doubling the // We can avoid this by doing linear correlation, effectively doubling the
// size of the input buffer and padding the code with zeros. // size of the input buffer and padding the code with zeros.
if (acq_parameters.bit_transition_flag) //if (acq_parameters.bit_transition_flag)
{ //{
d_fft_size = d_consumed_samples * 2; //d_fft_size = d_consumed_samples * 2;
acq_parameters.max_dwells = 1; // Activation of acq_parameters.bit_transition_flag invalidates the value of acq_parameters.max_dwells //acq_parameters.max_dwells = 1; // Activation of acq_parameters.bit_transition_flag invalidates the value of acq_parameters.max_dwells
} //}
d_tmp_buffer = volk_gnsssdr::vector<float>(d_fft_size); d_tmp_buffer = volk_gnsssdr::vector<float>(d_fft_size);
d_fft_codes = volk_gnsssdr::vector<std::complex<float>>(d_fft_size); d_fft_codes = volk_gnsssdr::vector<std::complex<float>>(d_fft_size);
@ -160,14 +161,14 @@ pcps_acquisition::pcps_acquisition(const Acq_Conf& conf_) : gr::block("pcps_acqu
d_samplesPerChip = acq_parameters.samples_per_chip; d_samplesPerChip = acq_parameters.samples_per_chip;
d_buffer_count = 0U; d_buffer_count = 0U;
// todo: CFAR statistic not available for non-coherent integration // todo: CFAR statistic not available for non-coherent integration
if (acq_parameters.max_dwells == 1) //if (acq_parameters.max_dwells == 1)
{ //{
d_use_CFAR_algorithm_flag = acq_parameters.use_CFAR_algorithm_flag; d_use_CFAR_algorithm_flag = acq_parameters.use_CFAR_algorithm_flag;
} //}
else //else
{ //{
d_use_CFAR_algorithm_flag = false; //d_use_CFAR_algorithm_flag = false;
} //}
d_dump_number = 0LL; d_dump_number = 0LL;
d_dump_channel = acq_parameters.dump_channel; d_dump_channel = acq_parameters.dump_channel;
d_dump = acq_parameters.dump; d_dump = acq_parameters.dump;
@ -364,7 +365,6 @@ void pcps_acquisition::set_state(int32_t state)
d_gnss_synchro->Acq_samplestamp_samples = 0ULL; d_gnss_synchro->Acq_samplestamp_samples = 0ULL;
d_gnss_synchro->Acq_doppler_step = 0U; d_gnss_synchro->Acq_doppler_step = 0U;
d_mag = 0.0; d_mag = 0.0;
d_input_power = 0.0;
d_test_statistics = 0.0; d_test_statistics = 0.0;
d_active = true; d_active = true;
} }
@ -382,7 +382,7 @@ void pcps_acquisition::send_positive_acquisition()
{ {
// Declare positive acquisition using a message port // Declare positive acquisition using a message port
// 0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL // 0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
DLOG(INFO) << "positive acquisition" LOG(INFO) << "positive acquisition"
<< ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN << ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN
<< ", sample_stamp " << d_sample_counter << ", sample_stamp " << d_sample_counter
<< ", test statistics value " << d_test_statistics << ", test statistics value " << d_test_statistics
@ -410,7 +410,7 @@ void pcps_acquisition::send_negative_acquisition()
{ {
// Declare negative acquisition using a message port // Declare negative acquisition using a message port
// 0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL // 0=STOP_CHANNEL 1=ACQ_SUCCEES 2=ACQ_FAIL
DLOG(INFO) << "negative acquisition" LOG(INFO) << "negative acquisition"
<< ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN << ", satellite " << d_gnss_synchro->System << " " << d_gnss_synchro->PRN
<< ", sample_stamp " << d_sample_counter << ", sample_stamp " << d_sample_counter
<< ", test statistics value " << d_test_statistics << ", test statistics value " << d_test_statistics
@ -533,12 +533,14 @@ float pcps_acquisition::max_to_input_power_statistic(uint32_t& indext, int32_t&
uint32_t index_doppler = 0U; uint32_t index_doppler = 0U;
uint32_t tmp_intex_t = 0U; uint32_t tmp_intex_t = 0U;
uint32_t index_time = 0U; uint32_t index_time = 0U;
float fft_normalization_factor = static_cast<float>(d_fft_size) * static_cast<float>(d_fft_size); int32_t effective_fft_size = (acq_parameters.bit_transition_flag ? d_fft_size / 2 : d_fft_size);
float fft_normalization_factor = static_cast<float>(effective_fft_size) * static_cast<float>(d_fft_size);
fft_normalization_factor *= fft_normalization_factor;
// Find the correlation peak and the carrier frequency // Find the correlation peak and the carrier frequency
for (uint32_t i = 0; i < num_doppler_bins; i++) for (uint32_t i = 0; i < num_doppler_bins; i++)
{ {
volk_gnsssdr_32f_index_max_32u(&tmp_intex_t, d_magnitude_grid[i].data(), d_fft_size); volk_gnsssdr_32f_index_max_32u(&tmp_intex_t, d_magnitude_grid[i].data(), effective_fft_size);
if (d_magnitude_grid[i][tmp_intex_t] > grid_maximum) if (d_magnitude_grid[i][tmp_intex_t] > grid_maximum)
{ {
grid_maximum = d_magnitude_grid[i][tmp_intex_t]; grid_maximum = d_magnitude_grid[i][tmp_intex_t];
@ -549,6 +551,8 @@ float pcps_acquisition::max_to_input_power_statistic(uint32_t& indext, int32_t&
indext = index_time; indext = index_time;
if (!d_step_two) if (!d_step_two)
{ {
int index_opp = (index_doppler + d_num_doppler_bins/2) % d_num_doppler_bins;
d_input_power = std::accumulate( d_magnitude_grid[index_opp].data(), d_magnitude_grid[index_opp].data()+effective_fft_size, 0.0 )/effective_fft_size/2.0/d_num_noncoherent_integrations_counter;
doppler = -static_cast<int32_t>(doppler_max) + d_doppler_center + doppler_step * static_cast<int32_t>(index_doppler); doppler = -static_cast<int32_t>(doppler_max) + d_doppler_center + doppler_step * static_cast<int32_t>(index_doppler);
} }
else else
@ -556,8 +560,7 @@ float pcps_acquisition::max_to_input_power_statistic(uint32_t& indext, int32_t&
doppler = static_cast<int32_t>(d_doppler_center_step_two + (static_cast<float>(index_doppler) - static_cast<float>(floor(d_num_doppler_bins_step2 / 2.0))) * acq_parameters.doppler_step2); doppler = static_cast<int32_t>(d_doppler_center_step_two + (static_cast<float>(index_doppler) - static_cast<float>(floor(d_num_doppler_bins_step2 / 2.0))) * acq_parameters.doppler_step2);
} }
float magt = grid_maximum / (fft_normalization_factor * fft_normalization_factor); return grid_maximum / d_input_power;
return magt / input_power;
} }
@ -652,7 +655,6 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
} }
const gr_complex* in = d_input_signal.data(); // Get the input samples pointer const gr_complex* in = d_input_signal.data(); // Get the input samples pointer
d_input_power = 0.0;
d_mag = 0.0; d_mag = 0.0;
d_num_noncoherent_integrations_counter++; d_num_noncoherent_integrations_counter++;
@ -665,13 +667,13 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
lk.unlock(); lk.unlock();
if (d_use_CFAR_algorithm_flag or acq_parameters.bit_transition_flag) //if (d_use_CFAR_algorithm_flag or acq_parameters.bit_transition_flag)
{ //{
// Compute the input signal power estimation //// Compute the input signal power estimation
volk_32fc_magnitude_squared_32f(d_tmp_buffer.data(), in, d_fft_size); //volk_32fc_magnitude_squared_32f(d_tmp_buffer.data(), in, d_fft_size);
volk_32f_accumulator_s32f(&d_input_power, d_tmp_buffer.data(), d_fft_size); //volk_32f_accumulator_s32f(&d_input_power, d_tmp_buffer.data(), d_fft_size);
d_input_power /= static_cast<float>(d_fft_size); //d_input_power /= static_cast<float>(d_fft_size);
} //}
// Doppler frequency grid loop // Doppler frequency grid loop
if (!d_step_two) if (!d_step_two)
@ -815,6 +817,7 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
d_positive_acq = 0; d_positive_acq = 0;
d_state = 0; d_state = 0;
} }
calculate_threshold();
} }
else else
{ {
@ -836,7 +839,12 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
} }
d_state = 0; d_state = 0;
d_active = false; d_active = false;
bool was_step_two = d_step_two;
d_step_two = false; d_step_two = false;
if( was_step_two )
{
calculate_threshold();
}
} }
} }
else else
@ -858,6 +866,7 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
d_num_noncoherent_integrations_counter = 0U; d_num_noncoherent_integrations_counter = 0U;
d_state = 0; d_state = 0;
} }
calculate_threshold();
} }
else else
{ {
@ -868,7 +877,10 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
else else
{ {
d_state = 0; // Negative acquisition d_state = 0; // Negative acquisition
bool was_step_two = d_step_two;
d_step_two = false; d_step_two = false;
if( was_step_two )
calculate_threshold();
send_negative_acquisition(); send_negative_acquisition();
} }
} }
@ -899,9 +911,24 @@ void pcps_acquisition::acquisition_core(uint64_t samp_count)
bool pcps_acquisition::start() bool pcps_acquisition::start()
{ {
d_sample_counter = 0ULL; d_sample_counter = 0ULL;
calculate_threshold();
return true; return true;
} }
void pcps_acquisition::calculate_threshold(void)
{
float pfa = ( d_step_two ? acq_parameters.pfa2 : acq_parameters.pfa );
if( pfa <= 0.0 )
return;
int effective_fft_size = (acq_parameters.bit_transition_flag ? (d_fft_size / 2) : d_fft_size);
int num_doppler_bins = ( d_step_two ? d_num_doppler_bins_step2 : d_num_doppler_bins );
int num_bins = effective_fft_size * num_doppler_bins;
d_threshold = 2.0*boost::math::gamma_p_inv( 2*acq_parameters.max_dwells, std::pow( 1.0 - pfa, 1.0/static_cast<double>(num_bins) ) );
}
int pcps_acquisition::general_work(int noutput_items __attribute__((unused)), int pcps_acquisition::general_work(int noutput_items __attribute__((unused)),
gr_vector_int& ninput_items, gr_vector_int& ninput_items,

1
src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.h
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@ -267,6 +267,7 @@ private:
void dump_results(int32_t effective_fft_size); void dump_results(int32_t effective_fft_size);
bool is_fdma(); bool is_fdma();
bool start(); bool start();
void calculate_threshold(void);
float first_vs_second_peak_statistic(uint32_t& indext, int32_t& doppler, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step); float first_vs_second_peak_statistic(uint32_t& indext, int32_t& doppler, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
float max_to_input_power_statistic(uint32_t& indext, int32_t& doppler, float input_power, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step); float max_to_input_power_statistic(uint32_t& indext, int32_t& doppler, float input_power, uint32_t num_doppler_bins, int32_t doppler_max, int32_t doppler_step);
}; };