{TAIL ~ An elevation drive unit} supported by the θ drive elevates/lowers an elevation frame under the control of {HEAD ~ an elevation control unit} 
{ TAIL ~ An elevation drive unit } supported by the θ drive elevates / lowers an elevation frame under the control of { HEAD ~ an elevation control unit }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD