def ais_rx(self, src, freq, designator, options, queue):
self.rate = options.rate
self.u = src
self.coeffs = firdes.low_pass(1,self.rate,7000,1000)
self._filter_decimation = 4
self.filter = filter.freq_xlating_fir_filter_ccf(self._filter_decimation,
self.coeffs,
freq,
self.rate)
self._bits_per_sec = 9600.0;
self._samples_per_symbol = self.rate / self._filter_decimation / self._bits_per_sec
options.samples_per_symbol = self._samples_per_symbol
options.gain_mu = 0.3
options.mu=0.5
options.omega_relative_limit = 0.0001
options.bits_per_sec = self._bits_per_sec
#trades off accuracy of freq estimation in presence of noise, vs. delay time.
options.fftlen = 4096
options.samp_rate = self.rate / self._filter_decimation
#ais_demod.py, hierarchical demodulation block, takes in complex baseband and spits out 1-bit packed bitstream
self.demod = ais_demod(options)
self.unstuff = unstuff() #ais_unstuff.cc, unstuffs data
#should mark start of packet
self.start_correlator = digital.correlate_access_code_tag_bb("1010101010101010", 0, "ais_preamble")
#should mark start and end of packet
self.stop_correlator = digital.correlate_access_code_tag_bb("01111110", 0, "ais_frame")
#ais_parse.cc, calculates CRC, parses data into ASCII message, moves data onto queue
self.parse = parse(queue, designator, options.verbose, options.lon, options.lat)
self.connect(self.u, self.filter, self.demod, self.unstuff, self.start_correlator, self.stop_correlator, self.parse)
def __init__(self, freq, rate, designator):
gr.hier_block2.__init__(self,
"ais_rx",
gr.io_signature(1,1,gr.sizeof_gr_complex),
gr.io_signature(0,0,0))
self._bits_per_sec = 9600.0
self._samples_per_symbol = 5
self.coeffs = filter.firdes.low_pass(1, rate, 11000, 1000)
self._filter_decimation = int(rate/(self._bits_per_sec*self._samples_per_symbol))
self.filter = filter.freq_xlating_fir_filter_ccf(self._filter_decimation,
self.coeffs,
freq,
rate)
# self.resamp = pfb.arb_resampler_ccf((self._bits_per_sec*self._samples_per_symbol)/int(rate/self._filter_decimation))
options = {}
options[ "samples_per_symbol" ] = (rate/self._filter_decimation)/self._bits_per_sec
options[ "clockrec_gain" ] = 0.04
options[ "omega_relative_limit" ] = 0.01
options[ "bits_per_sec" ] = self._bits_per_sec
options[ "fftlen" ] = 1024 #trades off accuracy of freq estimation in presence of noise, vs. delay time.
options[ "samp_rate" ] = self._bits_per_sec * self._samples_per_symbol
self.demod = ais.ais_demod(options) #ais_demod takes in complex baseband and spits out 1-bit unpacked bitstream
self.deframer = digital.hdlc_deframer_bp(11,64) #takes bytes, deframes, unstuffs, CRCs, and emits PDUs with frame contents
self.nmea = ais.pdu_to_nmea(designator) #turns data PDUs into NMEA sentences
# self.msgq = ais.pdu_to_msgq(queue) #posts PDUs to message queue for main program to parse at will
# self.parse = ais.parse(queue, designator) #ais_parse.cc, calculates CRC, parses data into NMEA AIVDM message, moves data onto queue
self.connect(self,
self.filter,
self.demod,
self.deframer)
self.msg_connect(self.deframer, "out", self.nmea, "print")
def __init__(self, freq, rate, designator):
gr.hier_block2.__init__(self,
"ais_rx",
gr.io_signature(1,1,gr.sizeof_gr_complex),
gr.io_signature(0,0,0))
self._bits_per_sec = 9600.0
self._samples_per_symbol = 5
self.coeffs = filter.firdes.low_pass(1, rate, 11000, 1000)
self._filter_decimation = int(rate/(self._bits_per_sec*self._samples_per_symbol))
self.filter = filter.freq_xlating_fir_filter_ccf(self._filter_decimation,
self.coeffs,
freq,
rate)
# self.resamp = pfb.arb_resampler_ccf((self._bits_per_sec*self._samples_per_symbol)/int(rate/self._filter_decimation))
options = {}
options[ "samples_per_symbol" ] = (rate/self._filter_decimation)/self._bits_per_sec
options[ "clockrec_gain" ] = 0.04
options[ "omega_relative_limit" ] = 0.01
options[ "bits_per_sec" ] = self._bits_per_sec
options[ "fftlen" ] = 1024 #trades off accuracy of freq estimation in presence of noise, vs. delay time.
options[ "samp_rate" ] = self._bits_per_sec * self._samples_per_symbol
self.demod = ais.ais_demod(options) #ais_demod takes in complex baseband and spits out 1-bit unpacked bitstream
self.deframer = digital.hdlc_deframer_bp(11,64) #takes bytes, deframes, unstuffs, CRCs, and emits PDUs with frame contents
self.nmea = ais.pdu_to_nmea(designator) #turns data PDUs into NMEA sentences
# self.msgq = ais.pdu_to_msgq(queue) #posts PDUs to message queue for main program to parse at will
# self.parse = ais.parse(queue, designator) #ais_parse.cc, calculates CRC, parses data into NMEA AIVDM message, moves data onto queue
self.connect(self,
self.filter,
self.demod,
self.deframer)
self.msg_connect(self.deframer, "out", self.nmea, "print")
def __init__(self, freq, rate, designator, queue, use_viterbi=False):
gr.hier_block2.__init__(self,
"ais_rx",
gr.io_signature(1,1,gr.sizeof_gr_complex),
gr.io_signature(0,0,0))
self.coeffs = filter.firdes.low_pass(1, rate, 7000, 1000)
self._filter_decimation = 12 #fixed, TODO make settable via params or better yet do resampling
self.filter = filter.freq_xlating_fir_filter_ccf(self._filter_decimation,
self.coeffs,
freq,
rate)
self._bits_per_sec = 9600.0
self._samples_per_symbol = rate / self._filter_decimation / self._bits_per_sec
options = {}
options[ "viterbi" ] = use_viterbi
options[ "samples_per_symbol" ] = self._samples_per_symbol
options[ "gain_mu" ] = 0.3
options[ "mu" ] = 0.5
options[ "omega_relative_limit" ] = 0.003
options[ "bits_per_sec" ] = self._bits_per_sec
options[ "fftlen" ] = 4096 #trades off accuracy of freq estimation in presence of noise, vs. delay time.
options[ "samp_rate" ] = rate / self._filter_decimation
self.demod = ais.ais_demod(options) #ais_demod takes in complex baseband and spits out 1-bit packed bitstream
self.unstuff = ais.unstuff() #undoes bit stuffing operation
self.start_correlator = digital.correlate_access_code_tag_bb("1010101010101010", 0, "ais_preamble") #should mark start of packet
self.stop_correlator = digital.correlate_access_code_tag_bb("01111110", 0, "ais_frame") #should mark start and end of packet
self.parse = ais.parse(queue, designator) #ais_parse.cc, calculates CRC, parses data into NMEA AIVDM message, moves data onto queue
self.connect(self,
self.filter,
self.demod,
self.unstuff,
self.start_correlator,
self.stop_correlator,
self.parse) #parse posts messages to the queue, which the main loop reads and prints
