Add coarse doppler shift correction block

grc/CMakeLists.txt

@@ -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
 )

grc/satnogs_coarse_doppler_correction_cc.xml

@@ -0,0 +1,37 @@
+<?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>

include/satnogs/CMakeLists.txt

@@ -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
 )

include/satnogs/coarse_doppler_correction_cc.h

@@ -0,0 +1,63 @@
+/* -*- 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 */
+

include/satnogs/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

lib/CMakeLists.txt

@@ -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)

lib/coarse_doppler_correction_cc_impl.cc

@@ -0,0 +1,128 @@
+/* -*- 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 */
+

lib/coarse_doppler_correction_cc_impl.h

@@ -0,0 +1,65 @@
+/* -*- 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 */
+

swig/satnogs_swig.i

@@ -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);