The system includes {HEAD ~ both a satellite positioning system} and {TAIL ~ a non SATPS unit} for obtaining position data 
The system includes { HEAD ~ both a satellite positioning system } and { TAIL ~ a non SATPS unit } for obtaining position data
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH