{HEAD ~ Training} is {TAIL ~ a series} of steps in which 3 D image data and other 3 D data are combined into a 3 D model of a vehicle being navigated 
is
{ HEAD ~ Training } is { TAIL ~ a series } of steps in which 3 D image data and other 3 D data are combined into a 3 D model of a vehicle being navigated
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 OTH OTH OTH OTH OTH