The method further comprises measuring {TAIL ~ the first and second components} based on {HEAD ~ the error signal} and the repeatable component 
The method further comprises measuring { TAIL ~ the first and second components } based on { HEAD ~ the error signal } and the repeatable component
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH