TriPoint VertexRSI 7200, Operation And Maintenance Manual

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O V ERVIE W
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2.9.3 St e pt r ack
Steptrack mode prov i des automat i c per i od i c pos i t i on i ng of the antenna for max i mum
rece i ve s i gna l strength as measured at the A C U track i ng s i gna l i nput. The 7 2 0 0 A C U
ut ili zes the V ertex A dapt i ve Steptrack (A ST) a l gor i thm to perform the funct i on of
convent i ona l steptrack peak s i gna l opt i m i zat i on, e li m i nat i ng the random " guess i ng "
errors assoc i ated w i th predeterm i ned f i xed scan patterns. A ST emp l oys a l ternate A Z
and EL peak i ng operat i ons based upon a mathemat i ca l re l at i onsh i p bet w een the
change i n rece i ve s i gna l l eve l and a g i ven change i n angu l ar antenna pos i t i on. For
each ax i s, an i n i t i a l f i xed-s i ze step i s taken, and s i gna l strength l eve l s before and after
the step are used to determ i ne the magn i tude and d i rect i on of the correct i ve
(peak i ng) step requ i red. Once the peak pos i t i on i s determ i ned, f l ags are set,
i nd i cat i ng the d i rect i on of trave l of the sate lli te so that the i n i t i a l step for the next
peak i ng operat i on w ill tend to move the antenna a l ong the sate lli te ephemer i s. Th i s
feature great l y reduces the errors i ntroduced by the " wrong " guess made dur i ng
s i gn i f i cant port i ons of the da il y sate lli te dr i ft by a l gor i thms w h i ch cons i stent l y make
i n i t i a l steps i n a g i ven d i rect i on.
Steptrack peak i ng operat i ons are performed at user-def i nab l e t i me i nterva l s, or w hen
the rece i ve s i gna l l eve l fa ll s be l o w a user-settab l e thresho l d. Steptrack i ng parameters,
i nc l ud i ng track i ng s i gna l frequency, cyc l e t i me, track thresho l d, etc., are estab li shed
for each target, a ll o w i ng max i mum versat ili ty for the system. (Refer to paragraph
5.8.2.4.3.)
2.9.4 St a r T r ack i ng
A utomat i c St a r t r ack i ng i s prov i ded as an a i d i n perform i ng antenna ga i n ca l cu l at i ons
by the rad i o star method. Such measurements requ i re cons i stent, accurate
pos i t i on i ng a l ong the path of a star w i th re l at i ve l y h i gh ve l oc i ty. Th i s can be done by
manua l pos i t i on i ng, but automat i c po i nt i ng a ll o w s for more accurate tests, performed
i n l ess t i me. A utomat i c po i nt i ng for stars i nc l ud i ng Cass i ope i a A , Taurus, and Or i on i s
supported, based upon s i te l ocat i on coord i nates.