Complex sentence: Two of the satellites in this series, numbers 35 and 36, are equipped with laser retro-reflectors, allowing them to be tracked independently of their radio signals, providing unambiguous separation of clock and ephemeris errors.
Split into simpler sentences: Two of the satellites in this series, numbers 35 and 36, are equipped with laser retro-reflectors. They can therefore be tracked independently of their radio signals, allowing unambiguous separation of clock and ephemeris errors.