Esempio n. 1
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def parse_rinex_nav_msg_gps(file_name):
  ephems = []
  got_header = False
  rinex_ver = None
  #ion_alpha = None
  #ion_beta = None
  f = open(file_name, 'r')
  while True:
    line = f.readline()[:-1]
    if not line:
      break
    if not got_header:
      if rinex_ver is None:
        if line[60:80] != "RINEX VERSION / TYPE":
          raise RuntimeError("Doesn't appear to be a RINEX file")
        rinex_ver = int(float(line[0:9]))
        if line[20] != "N":
          raise RuntimeError("Doesn't appear to be a Navigation Message file")
      #if line[60:69] == "ION ALPHA":
      #  line = line.replace('D', 'E')  # Handle bizarro float format
      #  ion_alpha= [float(line[3:14]), float(line[15:26]), float(line[27:38]), float(line[39:50])]
      #if line[60:68] == "ION BETA":
      #  line = line.replace('D', 'E')  # Handle bizarro float format
      #  ion_beta= [float(line[3:14]), float(line[15:26]), float(line[27:38]), float(line[39:50])]
      if line[60:73] == "END OF HEADER":
        #ion = ion_alpha + ion_beta
        got_header = True
      continue
    if rinex_ver == 3:
      if line[0] != 'G':
        continue
    if rinex_ver == 3:
      prn = int(line[1:3])
      epoch = GPSTime.from_datetime(datetime.strptime(line[4:23], "%y %m %d %H %M %S"))
    elif rinex_ver == 2:
      prn = int(line[0:2])
      epoch = GPSTime.from_datetime(datetime.strptime(line[3:20], "%y %m %d %H %M %S"))
      line = ' ' + line  # Shift 1 char to the right

    line = line.replace('D', 'E')  # Handle bizarro float format
    e = {'epoch': epoch, 'prn': prn}
    e['toc'] = epoch
    e['af0'] = float(line[23:42])
    e['af1'] = float(line[42:61])
    e['af2'] = float(line[61:80])

    e['iode'], e['crs'], e['dn'], e['m0'] = read4(f, rinex_ver)
    e['cuc'], e['ecc'], e['cus'], e['sqrta'] = read4(f, rinex_ver)
    toe_tow, e['cic'], e['omega0'], e['cis'] = read4(f, rinex_ver)
    e['inc'], e['crc'], e['w'], e['omegadot'] = read4(f, rinex_ver)
    e['inc_dot'], e['l2_codes'], toe_week, e['l2_pflag'] = read4(f, rinex_ver)
    e['sv_accuracy'], e['health'], e['tgd'], e['iodc'] = read4(f, rinex_ver)
    f.readline()  # Discard last row

    e['toe'] = GPSTime(toe_week, toe_tow)
    e['healthy'] = (e['health'] == 0.0)

    ephems.append(GPSEphemeris(e, epoch))
  f.close()
  return ephems
Esempio n. 2
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def convert_ublox_ephem(ublox_ephem):
    ephem = {}
    if ublox_ephem.gpsWeek < 1024:
        week = ublox_ephem.gpsWeek + 1024
    else:
        week = ublox_ephem.gpsWeek
    ephem['toe'] = GPSTime(week, ublox_ephem.toe)
    ephem['toc'] = GPSTime(week, ublox_ephem.toc)
    ephem['af0'] = ublox_ephem.af0
    ephem['af1'] = ublox_ephem.af1
    ephem['af2'] = ublox_ephem.af2
    ephem['tgd'] = ublox_ephem.tgd

    ephem['sqrta'] = np.sqrt(ublox_ephem.a)
    ephem['dn'] = ublox_ephem.deltaN
    ephem['m0'] = ublox_ephem.m0

    ephem['ecc'] = ublox_ephem.ecc
    ephem['w'] = ublox_ephem.omega
    ephem['cus'] = ublox_ephem.cus
    ephem['cuc'] = ublox_ephem.cuc
    ephem['crc'] = ublox_ephem.crc
    ephem['crs'] = ublox_ephem.crs
    ephem['cic'] = ublox_ephem.cic
    ephem['cis'] = ublox_ephem.cis

    ephem['inc'] = ublox_ephem.i0
    ephem['inc_dot'] = ublox_ephem.iDot
    ephem['omegadot'] = ublox_ephem.omegaDot
    ephem['omega0'] = ublox_ephem.omega0

    return ephem
Esempio n. 3
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  def __init__(self, exp, data1, data2):
    self.exp = exp
    self.grid_TEC1 = np.array([], dtype='uint16')
    self.grid_TEC2 = np.array([], dtype='uint16')
    self.t1 = GPSTime.from_datetime(dt.datetime(*map(int, data1[0].split()[:6])))
    self.t2 = GPSTime.from_datetime(dt.datetime(*map(int, data2[0].split()[:6])))
    #assert self.t2 - self.t1 == SECS_IN_HR
    assert len(data1) == len(data2)

    self.max_time_diff = SECS_IN_MIN*30
    self.epoch = self.t1 + self.max_time_diff

    self.lats = np.array([])
    for j, line in enumerate(data1[1:]):
      if "LAT" in line:
        lat, lon1, lon2, dlon, h = map(float, [line[x:x + 6] for x in range(2, 32, 6)])
        self.lats = np.append(self.lats, lat)
        row_length = (lon2 - lon1) / dlon + 1  # total number of values of longitudes
        next_lines_with_numbers = int(np.ceil(row_length / 16))
        elems_in_row = [
          min(16, int(row_length - i * 16)) for i in range(next_lines_with_numbers)
        ]
        row = np.array([], dtype='int16')
        for i, elem in enumerate(elems_in_row):
          row = np.append(row,
                          np.fromiter(
                            map(int,
                                [data1[j + 2 + i][5 * x:5 * x + 5] for x in range(elem)]),
                            dtype='int16'))
        if len(self.grid_TEC1) > 0:
          self.grid_TEC1 = np.vstack((self.grid_TEC1, row))
        else:
          self.grid_TEC1 = np.append(self.grid_TEC1, row)
    self.lons = np.linspace(lon1, lon2, row_length)


    self.lats = np.array([])
    for j, line in enumerate(data2[1:]):
      if "LAT" in line:
        lat, lon1, lon2, dlon, h = map(float, [line[x:x + 6] for x in range(2, 32, 6)])
        self.lats = np.append(self.lats, lat)
        row_length = (lon2 - lon1) / dlon + 1  # total number of values of longitudes
        next_lines_with_numbers = int(np.ceil(row_length / 16))
        elems_in_row = [
          min(16, int(row_length - i * 16)) for i in range(next_lines_with_numbers)
        ]
        row = np.array([], dtype='int16')
        for i, elem in enumerate(elems_in_row):
          row = np.append(row,
                          np.fromiter(
                            map(int,
                                [data2[j + 2 + i][5 * x:5 * x + 5] for x in range(elem)]),
                            dtype='int16'))
        if len(self.grid_TEC2) > 0:
          self.grid_TEC2 = np.vstack((self.grid_TEC2, row))
        else:
          self.grid_TEC2 = np.append(self.grid_TEC2, row)
    self.lons = np.linspace(lon1, lon2, row_length)
Esempio n. 4
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def download_nav(time, cache_dir, constellation='GPS'):
    t = time.as_datetime()
    try:
        if GPSTime.from_datetime(datetime.utcnow()) - time > SECS_IN_DAY:
            url_base = 'ftp://cddis.gsfc.nasa.gov/gnss/data/daily/'
            cache_subdir = cache_dir + 'daily_nav/'
            if constellation == 'GPS':
                filename = t.strftime("brdc%j0.%yn")
                folder_path = t.strftime('%Y/%j/%yn/')
            elif constellation == 'GLONASS':
                filename = t.strftime("brdc%j0.%yg")
                folder_path = t.strftime('%Y/%j/%yg/')
            return download_file(url_base,
                                 folder_path,
                                 cache_subdir,
                                 filename,
                                 compression='.Z')
        else:
            url_base = 'ftp://cddis.gsfc.nasa.gov/gnss/data/hourly/'
            cache_subdir = cache_dir + 'hourly_nav/'
            if constellation == 'GPS':
                filename = t.strftime("hour%j0.%yn")
                folder_path = t.strftime('%Y/%j/')
                return download_file(url_base,
                                     folder_path,
                                     cache_subdir,
                                     filename,
                                     compression='.Z',
                                     overwrite=True)
    except IOError:
        pass
Esempio n. 5
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def download_orbits_russia(time, cache_dir):
    cache_subdir = cache_dir + 'russian_products/'
    url_base = 'ftp://ftp.glonass-iac.ru/MCC/PRODUCTS/'
    downloaded_files = []
    for time in [time - SECS_IN_DAY, time, time + SECS_IN_DAY]:
        t = time.as_datetime()
        if GPSTime.from_datetime(datetime.utcnow()) - time > 2 * SECS_IN_WEEK:
            try:
                folder_path = t.strftime('%y%j/final/')
                filename = "Sta%i%i.sp3" % (time.week, time.day)
                downloaded_files.append(
                    download_file(url_base, folder_path, cache_subdir,
                                  filename))
                continue
            except IOError:
                pass
        try:
            folder_path = t.strftime('%y%j/rapid/')
            filename = "Sta%i%i.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base, folder_path, cache_subdir, filename))
        except IOError:
            pass
        try:
            folder_path = t.strftime('%y%j/ultra/')
            filename = "Sta%i%i.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base, folder_path, cache_subdir, filename))
        except IOError:
            pass
    return downloaded_files
Esempio n. 6
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File: dcb.py Progetto: tuandle/laika
def parse_dcbs(file_name, SUPPORTED_CONSTELLATIONS):
  with open(file_name, 'r+') as DCB_file:
    contents = DCB_file.readlines()
  data_started = False
  dcbs_dict = {}
  for line in contents:
    if not data_started:
      if line[1:4] == 'DSB':
        data_started = True
      else:
        continue
    line_components = line.split()
    if len(line_components[2]) < 3:
      break
    prn = line_components[2]
    if get_constellation(prn) not in SUPPORTED_CONSTELLATIONS:
      continue
    dcb_type = line_components[3] + '_' + line_components[4]
    epoch = GPSTime.from_datetime(datetime.strptime(line_components[5], '%Y:%j:%f')) + 12*SECS_IN_HR
    if prn not in dcbs_dict:
      dcbs_dict[prn] = {}
    dcbs_dict[prn][dcb_type] = float(line_components[8])
    dcbs_dict[prn]['epoch'] = epoch

  dcbs = []
  for prn in dcbs_dict:
    dcbs.append(DCB(prn, dcbs_dict[prn]))
  return dcbs
Esempio n. 7
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    def __init__(self,
                 prn,
                 recv_time_week,
                 recv_time_sec,
                 observables,
                 observables_std,
                 glonass_freq=np.nan):

        # Metadata
        self.prn = prn  # sattelite ID in rinex convention
        self.recv_time_week = recv_time_week
        self.recv_time_sec = recv_time_sec
        self.recv_time = GPSTime(recv_time_week, recv_time_sec)
        self.glonass_freq = glonass_freq  # glonass channel

        # Measurements
        self.observables = observables
        self.observables_std = observables_std

        # flags
        self.processed = False
        self.corrected = False

        # sat info
        self.sat_pos = np.nan * np.ones(3)
        self.sat_vel = np.nan * np.ones(3)
        self.sat_clock_err = np.nan

        self.sat_pos_final = np.nan * np.ones(
            3
        )  # sat_pos in receiver time's ECEF frame instead of sattelite time's ECEF frame
        self.observables_final = {}
Esempio n. 8
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def parse_rinex_nav_msg_glonass(file_name):
    ephems = []
    f = open(file_name, 'r')
    got_header = False
    rinex_ver = None
    while True:
        line = f.readline()[:-1]
        if not line:
            break
        if not got_header:
            if rinex_ver is None:
                if line[60:80] != "RINEX VERSION / TYPE":
                    raise RuntimeError("Doesn't appear to be a RINEX file")
                rinex_ver = int(float(line[0:9]))
                if line[20] != "G":
                    raise RuntimeError(
                        "Doesn't appear to be a Navigation Message file")
            if line[60:73] == "END OF HEADER":
                got_header = True
            continue
        if rinex_ver == 3:
            prn = line[:3]
            epoch = GPSTime.from_datetime(
                datetime.strptime(line[4:23], "%y %m %d %H %M %S"))
        elif rinex_ver == 2:
            prn = 'R%02i' % int(line[0:2])
            epoch = GPSTime.from_datetime(
                datetime.strptime(line[3:20], "%y %m %d %H %M %S"))
            line = ' ' + line  # Shift 1 char to the right

        line = line.replace('D', 'E')  # Handle bizarro float format
        e = {'epoch': epoch, 'prn': prn}
        e['toc'] = epoch
        e['min_tauN'] = float(line[23:42])
        e['GammaN'] = float(line[42:61])
        e['tk'] = float(line[61:80])

        e['x'], e['x_vel'], e['x_acc'], e['health'] = read4(f, rinex_ver)
        e['y'], e['y_vel'], e['y_acc'], e['freq_num'] = read4(f, rinex_ver)
        e['z'], e['z_vel'], e['z_acc'], e['age'] = read4(f, rinex_ver)

        e['healthy'] = (e['health'] == 0.0)

        ephems.append(GLONASSEphemeris(e, epoch))
    f.close()
    return ephems
Esempio n. 9
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def get_station_position(station_id,
                         cache_dir='/tmp/gnss/',
                         time=GPSTime.from_datetime(datetime.utcnow())):
    cors_station_positions_path = cache_dir + 'cors_coord/cors_station_positions'
    download_and_parse_station_postions(cors_station_positions_path, cache_dir)
    cors_station_positions_file = open(cors_station_positions_path, 'r')
    cors_station_positions_dict = np.load(cors_station_positions_file).item()
    cors_station_positions_file.close()
    epoch, pos, vel = cors_station_positions_dict[station_id]
    return ((time - epoch) / SECS_IN_YEAR) * np.array(vel) + np.array(pos)
Esempio n. 10
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def read_raw_qcom(report):
    recv_tow = (report.gpsMilliseconds) * 1.0 / 1000.0  # seconds
    recv_week = report.gpsWeek
    recv_time = GPSTime(recv_week, recv_tow)
    measurements = []
    for i in report.sv:
        svId = i.svId
        if not i.measurementStatus.measurementNotUsable and i.measurementStatus.satelliteTimeIsKnown:
            sat_tow = (i.unfilteredMeasurementIntegral +
                       i.unfilteredMeasurementFraction) / 1000
            sat_time = GPSTime(recv_week, sat_tow)
            observables, observables_std = {}, {}
            observables['C1C'] = (recv_time -
                                  sat_time) * constants.SPEED_OF_LIGHT
            observables_std[
                'C1C'] = i.unfilteredTimeUncertainty * 1e-3 * constants.SPEED_OF_LIGHT
            observables['D1C'] = i.unfilteredSpeed
            observables_std['D1C'] = i.unfilteredSpeedUncertainty
            observables['S1C'] = np.nan
            observables['L1C'] = np.nan
            measurements.append(
                GNSSMeasurement(get_prn_from_nmea_id(svId), recv_time.week,
                                recv_time.tow, observables, observables_std))
    return measurements
Esempio n. 11
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def read_raw_ublox(report):
    recv_tow = (report.rcvTow)  # seconds
    recv_week = report.gpsWeek
    recv_time = GPSTime(recv_week, recv_tow)
    measurements = []
    for i in report.measurements:
        # only add gps and glonass fixes
        if (i.gnssId == 0 or i.gnssId == 6):
            if i.svId > 32 or i.pseudorange > 2**32:
                continue
            if i.gnssId == 0:
                prn = 'G%02i' % i.svId
            else:
                prn = 'R%02i' % i.svId
            observables = {}
            observables_std = {}
            if i.trackingStatus.pseudorangeValid and i.sigId == 0:
                observables['C1C'] = i.pseudorange
                # Empirically it seems obvious ublox's std is
                # actually a variation
                observables_std['C1C'] = np.sqrt(i.pseudorangeStdev) * 10
                if i.gnssId == 6:
                    glonass_freq = i.glonassFrequencyIndex - 7
                    observables['D1C'] = -(constants.SPEED_OF_LIGHT /
                                           (constants.GLONASS_L1 + glonass_freq
                                            * constants.GLONASS_L1_DELTA)) * (
                                                i.doppler)
                elif i.gnssId == 0:
                    glonass_freq = np.nan
                    observables['D1C'] = -(constants.SPEED_OF_LIGHT /
                                           constants.GPS_L1) * (i.doppler)
                observables_std['D1C'] = (
                    constants.SPEED_OF_LIGHT /
                    constants.GPS_L1) * i.dopplerStdev * 1
                observables['S1C'] = i.cno
                if i.trackingStatus.carrierPhaseValid:
                    observables['L1C'] = i.carrierCycles
                else:
                    observables['L1C'] = np.nan
                measurements.append(
                    GNSSMeasurement(prn, recv_time.week, recv_time.tow,
                                    observables, observables_std,
                                    glonass_freq))
    return measurements
Esempio n. 12
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def download_and_parse_station_postions(cors_station_positions_path,
                                        cache_dir):
    if not os.path.isfile(cors_station_positions_path):
        cors_stations = {}
        coord_file_paths = download_cors_coords(cache_dir=cache_dir)
        for coord_file_path in coord_file_paths:
            try:
                station_id = coord_file_path.split('/')[-1][:4]
                with open(coord_file_path, 'r+') as coord_file:
                    contents = coord_file.readlines()
                phase_center = False
                for line_number in xrange(len(contents)):
                    if 'L1 Phase Center' in contents[line_number]:
                        phase_center = True
                    if not phase_center and 'IGS08 POSITION' in contents[
                            line_number]:
                        velocity = [
                            float(contents[line_number + 8].split()[3]),
                            float(contents[line_number + 9].split()[3]),
                            float(contents[line_number + 10].split()[3])
                        ]
                    if phase_center and 'IGS08 POSITION' in contents[
                            line_number]:
                        epoch = GPSTime.from_datetime(datetime(2005, 1, 1))
                        position = [
                            float(contents[line_number + 2].split()[3]),
                            float(contents[line_number + 3].split()[3]),
                            float(contents[line_number + 4].split()[3])
                        ]
                        cors_stations[station_id] = [epoch, position, velocity]
                        break
            except ValueError:
                pass
        cors_station_positions_file = open(cors_station_positions_path, 'w')
        np.save(cors_station_positions_file, cors_stations)
        cors_station_positions_file.close()
Esempio n. 13
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def read_rinex_obs(obsdata):
    measurements = []
    first_sat = obsdata.data.keys()[0]
    n = len(obsdata.data[first_sat]['Epochs'])
    for i in xrange(0, n):
        recv_time_datetime = obsdata.data[first_sat]['Epochs'][i]
        recv_time_datetime = recv_time_datetime.astype(datetime.datetime)
        recv_time = GPSTime.from_datetime(recv_time_datetime)
        measurements.append([])
        for sat_str in obsdata.data.keys():
            if np.isnan(obsdata.data[sat_str]['C1'][i]):
                continue
            observables, observables_std = {}, {}
            for obs in obsdata.data[sat_str]:
                if obs == 'Epochs':
                    continue
                observables[rinex3_obs_from_rinex2_obs(
                    obs)] = obsdata.data[sat_str][obs][i]
                observables_std[rinex3_obs_from_rinex2_obs(obs)] = 1
            measurements[-1].append(
                GNSSMeasurement(get_prn_from_nmea_id(int(sat_str)),
                                recv_time.week, recv_time.tow, observables,
                                observables_std))
    return measurements
Esempio n. 14
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def download_orbits(time, cache_dir):
    cache_subdir = cache_dir + 'cddis_products/'
    url_base = 'ftp://cddis.gsfc.nasa.gov/gnss/products/'
    downloaded_files = []
    for time in [time - SECS_IN_DAY, time, time + SECS_IN_DAY]:
        folder_path = "%i/" % (time.week)
        if GPSTime.from_datetime(datetime.utcnow()) - time > 3 * SECS_IN_WEEK:
            try:
                filename = "igs%i%i.sp3" % (time.week, time.day)
                downloaded_files.append(
                    download_file(url_base,
                                  folder_path,
                                  cache_subdir,
                                  filename,
                                  compression='.Z'))
                continue
            except IOError:
                pass
        try:
            filename = "igr%i%i.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base,
                              folder_path,
                              cache_subdir,
                              filename,
                              compression='.Z'))
            continue
        except IOError:
            pass
        try:
            filename = "igu%i%i_18.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base,
                              folder_path,
                              cache_subdir,
                              filename,
                              compression='.Z'))
            continue
        except IOError:
            pass
        try:
            filename = "igu%i%i_12.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base,
                              folder_path,
                              cache_subdir,
                              filename,
                              compression='.Z'))
            continue
        except IOError:
            pass
        try:
            filename = "igu%i%i_06.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base,
                              folder_path,
                              cache_subdir,
                              filename,
                              compression='.Z'))
            continue
        except IOError:
            pass
        try:
            filename = "igu%i%i_00.sp3" % (time.week, time.day)
            downloaded_files.append(
                download_file(url_base,
                              folder_path,
                              cache_subdir,
                              filename,
                              compression='.Z'))
            continue
        except IOError:
            pass
    return downloaded_files
Esempio n. 15
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def parse_sp3_orbits(file_names, SUPPORTED_CONSTELLATIONS):
    ephems = []
    data = {}
    for file_name in file_names:
        f = open(file_name, 'r')
        while True:
            line = f.readline()[:-1]
            if not line:
                break
            # epoch header
            if line[0:2] == '* ':
                year = int(line[3:7])
                month = int(line[8:10])
                day = int(line[11:13])
                hour = int(line[14:16])
                minute = int(line[17:19])
                second = int(float(line[20:31]))
                epoch = GPSTime.from_datetime(
                    datetime(year, month, day, hour, minute, second))
            # pos line
            elif line[0] == 'P':
                prn = line[1:4].replace(' ', '0')
                if get_constellation(prn) not in SUPPORTED_CONSTELLATIONS:
                    continue
                if prn not in data:
                    data[prn] = []
                #TODO this is a crappy way to deal with overlapping ultra rapid
                if len(data[prn]) < 1 or epoch - data[prn][-1][0] > 0:
                    parsed = [
                        epoch, 1e3 * float(line[4:18]),
                        1e3 * float(line[18:32]), 1e3 * float(line[32:46]),
                        1e-6 * float(line[46:60])
                    ]
                    if (np.array(parsed[1:]) != 0).all():
                        data[prn].append(parsed)
        f.close()
    deg = 16
    deg_t = 1
    for prn in data:
        # TODO Handle this properly
        # Currently don't even bother with satellites that have unhealthy times
        if (np.array(data[prn])[:, 4] > .99).any():
            continue
        for i in xrange(len(data[prn]) - deg):
            times, x, y, z, clock = [], [], [], [], []
            epoch = data[prn][i + deg / 2][0]
            for j in xrange(deg + 1):
                times.append(data[prn][i + j][0] - epoch)
                x.append(data[prn][i + j][1])
                y.append(data[prn][i + j][2])
                z.append(data[prn][i + j][3])
                clock.append(data[prn][i + j][4])
            if (np.diff(times) != 900).any():
                continue
            poly_data = {}
            poly_data['t0'] = epoch
            poly_data['x'] = np.polyfit(times, x, deg)
            poly_data['y'] = np.polyfit(times, y, deg)
            poly_data['z'] = np.polyfit(times, z, deg)
            poly_data['clock'] = [
                (data[prn][i + deg / 2 + 1][4] - data[prn][i + deg / 2 - 1][4])
                / 1800, data[prn][i + deg / 2][4]
            ]
            poly_data['deg'] = deg
            poly_data['deg_t'] = deg_t
            ephems.append(
                PolyEphemeris(prn,
                              poly_data,
                              epoch,
                              healthy=True,
                              eph_type=EphemerisType.RAPID_ORBIT))
    return ephems
Esempio n. 16
0
import numpy as np
from astro_dog import AstroDog
from datetime import datetime
from gps_time import GPSTime
import raw_gnss as raw
import helpers as helpers

dog = AstroDog()
time = GPSTime.from_datetime(datetime(2018, 1, 7))

# example data contains an array of raw GNSS observables
# that were recorded during a minute of highway driving of
# a car, this array format can be used to create Laika's
# GNSSMeasurent object which can be processed with astrodog
# to then be analysed or used for position estimated.
with open('raw_gnss_ublox/value', 'rb') as f:
    f.seek(0)
    example_data = np.load(f)

measurements = [raw.normal_meas_from_array(m_arr) for m_arr in example_data]

# lets limit this to GPS sattelite for the sake of simplicity
measurements = [
    m for m in measurements if helpers.get_constellation(m.prn) == 'GPS'
]
print('Exemplo de raw data de um satelite\n' + 'C1C = pseudorange\n' +
      'D1C = doppler\n' + 'L1C = carrier phase\n' + 'S1C = signal strength\n',
      measurements[0].observables)  #observables ta no formato rinex

# we organize the measurements by epoch and by sattelite for easy plotting
measurements_by_epoch = raw.group_measurements_by_epoch(