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