{HEAD ~ The basic SATPS method} may also be augmented by {TAIL ~ the use} of one or more reference stations at known locations 
augmented by
{ HEAD ~ The basic SATPS method } may also be augmented by { TAIL ~ the use } of one or more reference stations at known locations
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH