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Ship-avoiding operation  :  To operate the ship in order to avoid obstacles during automatic navigation, 
regardless of the scheduled route 
Sleeping AIS target  :  A target indicating the presence and orientation of a vessel equipped with AIS 
Spot depth  :  Numeric representation of depth 
SSR: Solid State Radar  :  Radar that uses semiconductor elements instead of magnetron, which 
requires periodic replacement. It is built with a system that ensures 
necessary detection capability even when a transmission output is low, by 
using chirp signals with a long pulse length upon transmission and 
performing pulse compression upon reception 
Update (Chart Maintenance) :  A procedure of reflecting the update data supplied by Update CD on the 
imported chart.