145 lines
4.7 KiB
Python
145 lines
4.7 KiB
Python
# Copyright 2013 Nick Foster
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#
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# This file is part of gr-air-modes
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#
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# gr-air-modes is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# any later version.
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#
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# gr-air-modes is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with gr-air-modes; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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# Radio interface for Mode S RX.
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# Handles all Gnuradio-related functionality.
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# You pass it options, it gives you data.
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# It uses the pubsub interface to allow clients to subscribe to its data feeds.
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from gnuradio import gr, gru, optfir, eng_notation, blks2
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from gnuradio.eng_option import eng_option
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from gnuradio.gr.pubsub import pubsub
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import air_modes
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DOWNLINK_DATA_TYPE = 'dl_data'
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class modes_radio (gr.top_block, pubsub):
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def __init__(self, options):
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gr.top_block.__init__(self)
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pubsub.__init__(self)
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self._options = options
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self._queue = gr.msg_queue()
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rate = int(options.rate)
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use_resampler = False
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self.time_source = None
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self._setup_source(options)
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self.subscribe('gain', self.set_gain)
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self.subscribe('freq', self.set_freq)
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self['gain'] = options.gain
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self['freq'] = options.freq
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self['rate'] = options.rate
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self['filename'] = options.filename
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#TODO allow setting rate, threshold (drill down into slicer & preamble)
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self.rx_path = air_modes.rx_path(rate, options.threshold, self._queue, options.pmf)
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if use_resampler:
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self.lpfiltcoeffs = gr.firdes.low_pass(1, 5*3.2e6, 1.6e6, 300e3)
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self.resample = blks2.rational_resampler_ccf(interpolation=5, decimation=4, taps=self.lpfiltcoeffs)
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self.connect(self._u, self.resample, self.rx_path)
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else:
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self.connect(self._u, self.rx_path)
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#Publish messages when they come back off the queue
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self._async_rcv = gru.msgq_runner(self._queue, self.async_callback)
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def async_callback(self, msg):
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self[DOWNLINK_DATA_TYPE] = msg.to_string()
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#these are wrapped with try/except because file sources and udp sources
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#don't have set_center_freq/set_gain functions. this should check to see
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#the type of self._u.
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def set_freq(self, freq):
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try:
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result = self._u.set_center_freq(freq, 0)
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return result
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except:
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pass
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def set_gain(self, gain):
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try:
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self._u.set_gain(gain)
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except:
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pass
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def _setup_source(self, options):
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if options.filename is None and options.udp is None and options.rtlsdr is None:
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#UHD source by default
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from gnuradio import uhd
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self._u = uhd.single_usrp_source(options.args, uhd.io_type_t.COMPLEX_FLOAT32, 1)
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if(options.subdev):
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self._u.set_subdev_spec(options.subdev, 0)
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#check for GPSDO
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#if you have a GPSDO, UHD will automatically set the timestamp to UTC time
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#as well as automatically set the clock to lock to GPSDO.
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if self._u.get_time_source(0) == 'gpsdo':
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self._time_source = 'gpsdo'
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else:
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self._time_source = None
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self._u.set_time_now(uhd.time_spec(0.0))
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if options.antenna is not None:
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self._u.set_antenna(options.antenna)
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self._u.set_samp_rate(rate)
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rate = int(self._u.get_samp_rate()) #retrieve actual
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if options.gain is None: #set to halfway
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g = self._u.get_gain_range()
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options.gain = (g.start()+g.stop()) / 2.0
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print "Setting gain to %i" % options.gain
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self._u.set_gain(options.gain)
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print "Gain is %i" % self._u.get_gain()
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elif options.rtlsdr: #RTLSDR dongle
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import osmosdr
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self._u = osmosdr.source_c(options.args)
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self._u.set_sample_rate(3.2e6) #fixed for RTL dongles
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if not self._u.set_center_freq(options.freq):
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print "Failed to set initial frequency"
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self._u.set_gain_mode(0) #manual gain mode
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if options.gain is None:
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options.gain = 34
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self._u.set_gain(options.gain)
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print "Gain is %i" % self._u.get_gain()
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use_resampler = True
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else:
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if options.filename is not None:
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self._u = gr.file_source(gr.sizeof_gr_complex, options.filename)
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elif options.udp is not None:
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self._u = gr.udp_source(gr.sizeof_gr_complex, "localhost", options.udp)
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else:
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raise Exception("No valid source selected")
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print "Rate is %i" % (options.rate,)
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