{HEAD ~ The apparatus} includes {TAIL ~ a first or reference station} that provides a reference for the survey and whose location is determined with high accuracy, and a second or mobile station that is spaced apart from the first station and acts as a mobile measurement unit for the survey 
includes
{ HEAD ~ The apparatus } includes { TAIL ~ a first or reference station } that provides a reference for the survey and whose location is determined with high accuracy , and a second or mobile station that is spaced apart from the first station and acts as a mobile measurement unit for the survey
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH