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Code Issues Releases Wiki Activity

Add first-to-second peak statistic

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This commit is contained in:
Carles Fernandez 2018-07-09 17:56:47 +02:00
parent d76dab6248
commit 6b67037fed
13 changed files with 85 additions and 44 deletions
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1
src/algorithms/acquisition/adapters/galileo_e1_pcps_ambiguous_acquisition.cc
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@ -58,6 +58,7 @@ GalileoE1PcpsAmbiguousAcquisition::GalileoE1PcpsAmbiguousAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 4000000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E1_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

1
src/algorithms/acquisition/adapters/galileo_e5a_pcps_acquisition.cc
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@ -57,6 +57,7 @@ GalileoE5aPcpsAcquisition::GalileoE5aPcpsAcquisition(ConfigurationInterface* con
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 32000000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / Galileo_E5a_CODE_CHIP_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
acq_pilot_ = configuration_->property(role + ".acquire_pilot", false);
acq_iq_ = configuration_->property(role + ".acquire_iq", false);
if (acq_iq_)

1
src/algorithms/acquisition/adapters/glonass_l1_ca_pcps_acquisition.cc
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@ -59,6 +59,7 @@ GlonassL1CaPcpsAcquisition::GlonassL1CaPcpsAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GLONASS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

1
src/algorithms/acquisition/adapters/glonass_l2_ca_pcps_acquisition.cc
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@ -58,6 +58,7 @@ GlonassL2CaPcpsAcquisition::GlonassL2CaPcpsAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GLONASS_L2_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

1
src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition.cc
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@ -60,6 +60,7 @@ GpsL1CaPcpsAcquisition::GpsL1CaPcpsAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

1
src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fine_doppler.cc
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@ -56,6 +56,7 @@ GpsL1CaPcpsAcquisitionFineDoppler::GpsL1CaPcpsAcquisitionFineDoppler(
long fs_in_deprecated = configuration->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration->property(role + ".dump", false);
acq_parameters.dump = dump_;
dump_filename_ = configuration->property(role + ".dump_filename", default_dump_filename);

1
src/algorithms/acquisition/adapters/gps_l1_ca_pcps_acquisition_fpga.cc
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@ -60,6 +60,7 @@ GpsL1CaPcpsAcquisitionFpga::GpsL1CaPcpsAcquisitionFpga(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
long fs_in = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(acq_parameters.fs_in)));
doppler_max_ = configuration_->property(role + ".doppler_max", 5000);
if (FLAGS_doppler_max != 0) doppler_max_ = FLAGS_doppler_max;
acq_parameters.doppler_max = doppler_max_;

1
src/algorithms/acquisition/adapters/gps_l2_m_pcps_acquisition.cc
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@ -60,6 +60,7 @@ GpsL2MPcpsAcquisition::GpsL2MPcpsAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L2_M_CODE_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

1
src/algorithms/acquisition/adapters/gps_l5i_pcps_acquisition.cc
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@ -59,6 +59,7 @@ GpsL5iPcpsAcquisition::GpsL5iPcpsAcquisition(
long fs_in_deprecated = configuration_->property("GNSS-SDR.internal_fs_hz", 2048000);
fs_in_ = configuration_->property("GNSS-SDR.internal_fs_sps", fs_in_deprecated);
acq_parameters.fs_in = fs_in_;
acq_parameters.samples_per_chip = static_cast<unsigned int>(ceil((1.0 / GPS_L5i_CODE_RATE_HZ) * static_cast<float>(acq_parameters.fs_in)));
dump_ = configuration_->property(role + ".dump", false);
acq_parameters.dump = dump_;
acq_parameters.dump_channel = configuration_->property(role + ".dump_channel", 0);

115
src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc
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@ -127,6 +127,7 @@ pcps_acquisition::pcps_acquisition(const Acq_Conf& conf_) : gr::block("pcps_acqu
d_step_two = false;
d_dump_number = 0;
d_dump_channel = acq_parameters.dump_channel;
samplesPerChip = acq_parameters.samples_per_chip;
}
@ -426,14 +427,72 @@ void pcps_acquisition::dump_results(int effective_fft_size)
}
}
float pcps_acquisition::first_vs_second_peak_statistics(uint32_t& indext, int& doppler)
{
float firstPeak = 0.0;
int index_doppler = 0;
uint32_t tmp_intex_t = 0;
uint32_t index_time = 0;
// Look for correlation peaks in the results ==============================
// Find the highest peak and compare it to the second highest peak
// The second peak is chosen not closer than 1 chip to the highest peak
//--- Find the correlation peak and the carrier frequency --------------
for (int i = 0; i < d_num_doppler_bins; i++)
{
volk_gnsssdr_32f_index_max_32u(&tmp_intex_t, d_magnitude_grid[i], d_fft_size);
if (d_magnitude_grid[i][tmp_intex_t] > firstPeak)
{
firstPeak = d_magnitude_grid[i][tmp_intex_t];
index_doppler = i;
index_time = tmp_intex_t;
}
}
indext = index_time;
doppler = -static_cast<int>(acq_parameters.doppler_max) + d_doppler_step * index_doppler;
// -- - Find 1 chip wide code phase exclude range around the peak
//uint32_t samplesPerChip = ceil(GPS_L1_CA_CHIP_PERIOD * static_cast<float>(this->d_fs_in));
int32_t excludeRangeIndex1 = index_time - samplesPerChip;
int32_t excludeRangeIndex2 = index_time + samplesPerChip;
// -- - Correct code phase exclude range if the range includes array boundaries
if (excludeRangeIndex1 < 0)
{
excludeRangeIndex1 = d_fft_size + excludeRangeIndex1;
}
else if (excludeRangeIndex2 >= static_cast<int>(d_fft_size))
{
excludeRangeIndex2 = excludeRangeIndex2 - d_fft_size;
}
int32_t idx = excludeRangeIndex1;
memcpy(d_tmp_buffer, d_magnitude_grid[index_doppler], d_fft_size);
do
{
d_tmp_buffer[idx] = 0.0;
idx++;
if (idx == static_cast<int>(d_fft_size)) idx = 0;
}
while (idx != excludeRangeIndex2);
//--- Find the second highest correlation peak in the same freq. bin ---
volk_gnsssdr_32f_index_max_32u(&tmp_intex_t, d_tmp_buffer, d_fft_size);
float secondPeak = d_tmp_buffer[tmp_intex_t];
// 5- Compute the test statistics and compare to the threshold
return firstPeak / secondPeak;
}
void pcps_acquisition::acquisition_core(unsigned long int samp_count)
{
gr::thread::scoped_lock lk(d_setlock);
// initialize acquisition algorithm
uint32_t indext = 0;
float magt = 0.0;
int doppler = 0;
uint32_t indext = 0;
const gr_complex* in = d_data_buffer; // Get the input samples pointer
int effective_fft_size = (acq_parameters.bit_transition_flag ? d_fft_size / 2 : d_fft_size);
if (d_cshort)
@ -466,9 +525,7 @@ void pcps_acquisition::acquisition_core(unsigned long int samp_count)
{
for (unsigned int doppler_index = 0; doppler_index < d_num_doppler_bins; doppler_index++)
{
// doppler search steps
int doppler = -static_cast<int>(acq_parameters.doppler_max) + d_doppler_step * doppler_index;
// Remove doppler
volk_32fc_x2_multiply_32fc(d_fft_if->get_inbuf(), in, d_grid_doppler_wipeoffs[doppler_index], d_fft_size);
// 3- Perform the FFT-based convolution (parallel time search)
@ -482,7 +539,7 @@ void pcps_acquisition::acquisition_core(unsigned long int samp_count)
// compute the inverse FFT
d_ifft->execute();
// Search maximum
// compute squared magnitude (and accumulate in case of non-coherent integration)
size_t offset = (acq_parameters.bit_transition_flag ? effective_fft_size : 0);
if (d_num_noncoherent_integrations_counter == 1)
{
@ -493,51 +550,21 @@ void pcps_acquisition::acquisition_core(unsigned long int samp_count)
volk_32fc_magnitude_squared_32f(d_tmp_buffer, d_ifft->get_outbuf() + offset, effective_fft_size);
volk_32f_x2_add_32f(d_magnitude_grid[doppler_index], d_magnitude_grid[doppler_index], d_tmp_buffer, effective_fft_size);
}
volk_gnsssdr_32f_index_max_32u(&indext, d_magnitude_grid[doppler_index], effective_fft_size);
magt = d_magnitude_grid[doppler_index][indext];
if (acq_parameters.use_CFAR_algorithm_flag)
{
// Normalize the maximum value to correct the scale factor introduced by FFTW
magt = magt / (fft_normalization_factor * fft_normalization_factor);
}
// 4- record the maximum peak and the associated synchronization parameters
if (d_mag < magt)
{
d_mag = magt;
if (!acq_parameters.use_CFAR_algorithm_flag)
{
// Search grid noise floor approximation for this doppler line
volk_32f_accumulator_s32f(&d_input_power, d_magnitude_grid[doppler_index], effective_fft_size);
d_input_power = (d_input_power - d_mag) / (effective_fft_size - 1);
}
// In case that acq_parameters.bit_transition_flag = true, we compare the potentially
// new maximum test statistics (d_mag/d_input_power) with the value in
// d_test_statistics. When the second dwell is being processed, the value
// of d_mag/d_input_power could be lower than d_test_statistics (i.e,
// the maximum test statistics in the previous dwell is greater than
// current d_mag/d_input_power). Note that d_test_statistics is not
// restarted between consecutive dwells in multidwell operation.
if (d_test_statistics < (d_mag / d_input_power) or !acq_parameters.bit_transition_flag)
{
d_gnss_synchro->Acq_delay_samples = static_cast<double>(indext % acq_parameters.samples_per_code);
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
d_gnss_synchro->Acq_samplestamp_samples = samp_count;
// 5- Compute the test statistics and compare to the threshold
//d_test_statistics = 2 * d_fft_size * d_mag / d_input_power;
d_test_statistics = d_mag / d_input_power;
}
}
// Record results to file if required
if (acq_parameters.dump and d_channel == d_dump_channel)
{
memcpy(grid_.colptr(doppler_index), d_magnitude_grid[doppler_index], sizeof(float) * effective_fft_size);
}
}
// 5- Compute the test statistics and compare to the threshold
float computed_statistic = first_vs_second_peak_statistics(indext, doppler);
if (d_test_statistics < computed_statistic or !acq_parameters.bit_transition_flag)
{
d_gnss_synchro->Acq_delay_samples = static_cast<double>(indext % acq_parameters.samples_per_code);
d_gnss_synchro->Acq_doppler_hz = static_cast<double>(doppler);
d_gnss_synchro->Acq_samplestamp_samples = samp_count;
d_test_statistics = computed_statistic;
}
}
else
{

3
src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.h
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@ -95,6 +95,8 @@ private:
void dump_results(int effective_fft_size);
float first_vs_second_peak_statistics(uint32_t& indext, int& doppler);
Acq_Conf acq_parameters;
bool d_active;
bool d_worker_active;
@ -108,6 +110,7 @@ private:
float* d_magnitude;
float** d_magnitude_grid;
float* d_tmp_buffer;
uint32_t samplesPerChip;
long d_old_freq;
int d_state;
unsigned int d_channel;

1
src/algorithms/acquisition/libs/acq_conf.cc
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@ -36,6 +36,7 @@ Acq_Conf::Acq_Conf()
/* PCPS acquisition configuration */
sampled_ms = 0;
max_dwells = 0;
samples_per_chip = 0;
doppler_max = 0;
num_doppler_bins_step2 = 0;
doppler_step2 = 0.0;

1
src/algorithms/acquisition/libs/acq_conf.h
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@ -40,6 +40,7 @@ class Acq_Conf
public:
/* PCPS Acquisition configuration */
unsigned int sampled_ms;
unsigned int samples_per_chip;
unsigned int max_dwells;
unsigned int doppler_max;
unsigned int num_doppler_bins_step2;