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osqzss / gps-sdr-sim

Software-Defined GPS Signal Simulator
MIT License
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Why is data in ephemeris divided by POW2_M*? #297

Closed yangfan852219770 closed 3 years ago

yangfan852219770 commented 3 years ago

In eph2sbf function, I don't understand why is some data read from the ephemeris divided by POW2_M*? Like this: cuc = (long)(eph.cuc/POW2_M29);

Mictronics commented 3 years ago

POW2_M* is a scale factor. See IS-GPS-200L for details. Table 20-III Ephemeris parameters. gpssim.h has the corresponding scale factors.

yangfan852219770 commented 3 years ago

Oh, my god! This is a stupid question! Because they have Scale Factor.