'Parses partial visible satellite information from a GSV sentence.'

def _fixGSV(self):

    beaconInformation = base.BeaconInformation()
    self._sentenceData['_partialBeaconInformation'] = beaconInformation
    keys = ('satellitePRN', 'azimuth', 'elevation', 'signalToNoiseRatio')
    for index in range(4):
        (prn, azimuth, elevation, snr) = [getattr(self.currentSentence, attr) for attr in (('%s_%i' % (key, index)) for key in keys)]
        if ((prn is None) or (snr is None)):
            continue
        satellite = base.Satellite(prn, azimuth, elevation, snr)
        beaconInformation.seenBeacons.add(satellite)
