def __init__(self,
                 identifier,
                 azimuth=None,
                 elevation=None,
                 signalToNoiseRatio=None):
        """
        Initializes a satellite object.

        @param identifier: The PRN (unique identifier) of this satellite.
        @type identifier: C{int}
        @param azimuth: The azimuth of the satellite (see instance variable
            documentation).
        @type azimuth: C{float}
        @param elevation: The elevation of the satellite (see instance variable
            documentation).
        @type elevation: C{float}
        @param signalToNoiseRatio: The signal to noise ratio of the connection
            to this satellite (see instance variable documentation).
        @type signalToNoiseRatio: C{float}
        """
        PositioningBeacon.__init__(self, int(identifier))

        self.azimuth = azimuth
        self.elevation = elevation
        self.signalToNoiseRatio = signalToNoiseRatio

        Initializes a satellite object.

        @param identifier: The PRN (unique identifier) of this satellite.
        @type identifier: C{int}
        @param azimuth: The azimuth of the satellite (see instance variable
            documentation).
        @type azimuth: C{float}
        @param elevation: The elevation of the satellite (see instance variable
            documentation).
        @type elevation: C{float}
        @param signalToNoiseRatio: The signal to noise ratio of the connection
            to this satellite (see instance variable documentation).
        @type signalToNoiseRatio: C{float}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/positioning/base.py