Commit c28c82c8 authored by Manolis Surligas's avatar Manolis Surligas

Add coarse doppler shift correction block

parent 8a81ebc4
......@@ -35,5 +35,6 @@ install(FILES
satnogs_upsat_fsk_frame_acquisition.xml
satnogs_upsat_fsk_frame_encoder.xml
satnogs_whitening.xml
satnogs_udp_msg_sink.xml DESTINATION share/gnuradio/grc/blocks
satnogs_udp_msg_sink.xml
satnogs_coarse_doppler_correction_cc.xml DESTINATION share/gnuradio/grc/blocks
)
<?xml version="1.0"?>
<block>
<name>Coarse Doppler Correction</name>
<key>satnogs_coarse_doppler_correction_cc</key>
<category>satnogs</category>
<import>import satnogs</import>
<make>satnogs.coarse_doppler_correction_cc($target_freq, $sampling_rate)</make>
<callback>set_new_freq_locked($target_freq)</callback>
<param>
<name>Target Frequency</name>
<key>target_freq</key>
<type>real</type>
</param>
<param>
<name>Sample Rate</name>
<key>sampling_rate</key>
<value>samp_rate</value>
<type>real</type>
</param>
<sink>
<name>freq</name>
<type>message</type>
</sink>
<sink>
<name>in</name>
<type>complex</type>
</sink>
<source>
<name>out</name>
<type>complex</type>
</source>
</block>
......@@ -48,5 +48,6 @@ install(FILES
upsat_fsk_frame_acquisition.h
upsat_fsk_frame_encoder.h
whitening.h
udp_msg_sink.h DESTINATION include/satnogs
udp_msg_sink.h
coarse_doppler_correction_cc.h DESTINATION include/satnogs
)
/* -*- c++ -*- */
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_H
#define INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_H
#include <satnogs/api.h>
#include <gnuradio/sync_block.h>
namespace gr
{
namespace satnogs
{
/*!
* \brief This block corrects the doppler effect between the ground
* station and the satellite in a coarse and very simplified way.
* Instead of changing the hardware center frequency, we use an NCO
* to digitally compensate the doppler effect.
*
* \ingroup satnogs
*
*/
class SATNOGS_API coarse_doppler_correction_cc : virtual public gr::sync_block
{
public:
typedef boost::shared_ptr<coarse_doppler_correction_cc> sptr;
/**
* The doppler correction block. The input is the complex signal at
* baseband as it comes from the SDR device.
*
* The message input \p freq receives periodically messages containing
* the predicted absolute frequency of the satellite at that specific time.
* @param target_freq the absolute frequency of the satellite
* @param sampling_rate the sampling rate of the signal
*/
static sptr
make (double target_freq, double sampling_rate);
};
} // namespace satnogs
} // namespace gr
#endif /* INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_H */
......@@ -48,7 +48,7 @@ namespace gr
* The doppler correction block. The input is the complex signal at
* baseband as it comes from the SDR device. The message input \p freq
* received periodically messages containing the predicted absolute
* frequency of the satellite at the moment of the
* frequency of the satellite at that specific time.
* @param target_freq the absolute frequency of the satellite
* @param sampling_rate the sampling rate of the signal
* @param corrections_per_sec the number of the corrections every second
......
......@@ -46,7 +46,8 @@ list(APPEND satnogs_sources
upsat_fsk_frame_acquisition_impl.cc
upsat_fsk_frame_encoder_impl.cc
whitening.cc
udp_msg_sink_impl.cc )
udp_msg_sink_impl.cc
coarse_doppler_correction_cc_impl.cc )
set(satnogs_sources "${satnogs_sources}" PARENT_SCOPE)
if(NOT satnogs_sources)
......
/* -*- c++ -*- */
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gnuradio/io_signature.h>
#include "coarse_doppler_correction_cc_impl.h"
#include <volk/volk.h>
namespace gr
{
namespace satnogs
{
coarse_doppler_correction_cc::sptr
coarse_doppler_correction_cc::make (double target_freq,
double sampling_rate)
{
return gnuradio::get_initial_sptr (
new coarse_doppler_correction_cc_impl (target_freq, sampling_rate));
}
/*
* The private constructor
*/
coarse_doppler_correction_cc_impl::coarse_doppler_correction_cc_impl (
double target_freq, double sampling_rate) :
gr::sync_block ("coarse_doppler_correction_cc",
gr::io_signature::make (1, 1, sizeof(gr_complex)),
gr::io_signature::make (1, 1, sizeof(gr_complex))),
d_target_freq (target_freq),
d_samp_rate (sampling_rate),
d_buf_items (std::min (8192UL, (size_t) (d_samp_rate / 4))),
d_freq_diff (0),
d_nco ()
{
message_port_register_in (pmt::mp ("freq"));
/*
* NOTE:
* Set the maximum number of samples to be equivalent of half a second.
* With this way we are sure that at least one frequency message
* per second will be processed.
*
* This is taken into consideration due to the fact that the work()
* and the input message handler are NOT reentrant.
*/
set_max_noutput_items (d_samp_rate / 4.0);
set_alignment (8);
set_msg_handler (
pmt::mp ("freq"),
boost::bind (&coarse_doppler_correction_cc_impl::new_freq, this, _1));
d_nco.set_freq (0);
/* Allocate aligned memory for the NCO */
d_nco_buff = (gr_complex *) volk_malloc (
(d_samp_rate / 4) * sizeof(gr_complex), 32);
if (!d_nco_buff) {
throw std::runtime_error ("Could not allocate NCO memory");
}
}
void
coarse_doppler_correction_cc_impl::new_freq (pmt::pmt_t msg)
{
boost::mutex::scoped_lock lock (d_mutex);
double new_freq;
new_freq = pmt::to_double (msg);
d_freq_diff = d_target_freq - new_freq;
d_nco.set_freq ((2 * M_PI * (-d_freq_diff)) / d_samp_rate);
}
/*
* Our virtual destructor.
*/
coarse_doppler_correction_cc_impl::~coarse_doppler_correction_cc_impl ()
{
volk_free (d_nco_buff);
}
int
coarse_doppler_correction_cc_impl::work (
int noutput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items)
{
const gr_complex *in = (const gr_complex *) input_items[0];
gr_complex *out = (gr_complex *) output_items[0];
/* Perform the correction */
d_nco.sincos (d_nco_buff, noutput_items, 1.0);
volk_32fc_x2_multiply_32fc (out, in, d_nco_buff, noutput_items);
// Tell runtime system how many output items we produced.
return noutput_items;
}
void
coarse_doppler_correction_cc_impl::set_target_freq (double freq)
{
boost::mutex::scoped_lock lock (d_mutex);
d_target_freq = freq;
d_freq_diff = 0.0;
d_nco.set_freq (0);
}
} /* namespace satnogs */
} /* namespace gr */
/* -*- c++ -*- */
/*
* gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
*
* Copyright (C) 2016, Libre Space Foundation <http://librespacefoundation.org/>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_IMPL_H
#define INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_IMPL_H
#include <satnogs/coarse_doppler_correction_cc.h>
#include <gnuradio/fxpt_nco.h>
namespace gr
{
namespace satnogs
{
class coarse_doppler_correction_cc_impl : public coarse_doppler_correction_cc
{
private:
double d_target_freq;
const double d_samp_rate;
const size_t d_buf_items;
double d_freq_diff;
gr::fxpt_nco d_nco;
gr_complex *d_nco_buff;
boost::mutex d_mutex;
void
new_freq (pmt::pmt_t msg);
public:
coarse_doppler_correction_cc_impl (double target_freq,
double sampling_rate);
~coarse_doppler_correction_cc_impl ();
// Where all the action really happens
int
work (int noutput_items, gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
void
set_target_freq (double freq);
};
} // namespace satnogs
} // namespace gr
#endif /* INCLUDED_SATNOGS_COARSE_DOPPLER_CORRECTION_CC_IMPL_H */
......@@ -29,6 +29,7 @@
#include "satnogs/upsat_fsk_frame_encoder.h"
#include "satnogs/whitening.h"
#include "satnogs/udp_msg_sink.h"
#include "satnogs/coarse_doppler_correction_cc.h"
%}
......@@ -70,3 +71,5 @@ GR_SWIG_BLOCK_MAGIC2(satnogs, upsat_fsk_frame_encoder);
%include "satnogs/whitening.h"
%include "satnogs/udp_msg_sink.h"
GR_SWIG_BLOCK_MAGIC2(satnogs, udp_msg_sink);
%include "satnogs/coarse_doppler_correction_cc.h"
GR_SWIG_BLOCK_MAGIC2(satnogs, coarse_doppler_correction_cc);
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