▁or ▁ship . ▁Ris ks ▁are ▁the ▁system ▁lock ing ▁on ▁other ▁reflect ing ▁objects ▁and ▁blocking ▁of ▁the ▁signal . ▁However , ▁the ▁C ys can ▁Ab solute ▁Sign ature ▁which ▁was ▁released ▁in ▁ 2 0 1 7 ▁was ▁launched ▁to ▁address ▁this ▁issue . ▁It ▁is ▁able ▁to ▁eng age ▁in ▁an ▁active ▁lock ▁with ▁the ▁Ab solute ▁Sign ature ▁pr ism ▁which ▁reduces ▁the ▁chance ▁of ▁a ▁wrong ▁target ▁being ▁track ed . ▁Range ▁depends ▁on ▁the ▁weather , ▁but ▁is ▁typically ▁more ▁than ▁ 5 0 0 ▁meters . ▁New ▁adv ancement ▁from ▁Gu id ance ▁Marine ▁led ▁to ▁the ▁development ▁of ▁the ▁Sc ene Scan ▁sensor ▁which ▁is ▁a ▁target - less ▁las er ▁PR S ▁lever aging ▁on ▁the ▁S LA M ▁algorithm . ▁Ar tem is . ▁A ▁rad ar - based ▁system . ▁A ▁unit ▁is ▁placed ▁on ▁a ▁F P SO ▁( Fixed ▁Station ) ▁and ▁the ▁unit ▁on ▁board ▁the ▁Sh utt le ▁T ank er ▁( Mobile ▁Station ) ▁lo cks ▁to ▁report ▁the ▁Range ▁and ▁Bear ing . ▁The ▁range ▁is ▁in ▁excess ▁of ▁ 4 ▁kilom eters . ▁Adv antage ▁is ▁the ▁reliable , ▁all - we ather ▁performance . ▁Dis adv antage ▁is ▁that ▁the ▁unit ▁is ▁rather ▁heavy ▁and ▁cost ly . ▁Current ▁version ▁is ▁the ▁Ar tem is ▁M k 6 . ▁D AR PS , ▁D iffer ential , ▁Ab solute ▁and ▁Rel ative ▁Position ing ▁System . ▁Comm only ▁used ▁on ▁sh utt le