Since {HEAD ~ SATPS data} gives {TAIL ~ good results} at longer distances, SATPS data is used when the distance is greater than or equal to the optical threshold 
gives
Since { HEAD ~ SATPS data } gives { TAIL ~ good results } at longer distances , SATPS data is used when the distance is greater than or equal to the optical threshold
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH