Your radar is set on a true motion display.Which of the following will NOT appear to move across the PPI scope（）.

单项选择题Your radar displays your ship off center．As you proceed on your course， your ship’s marker moves on the PPI scope while echoes from land masses remain stationary.What is this display called（）.

A.Off center
B.True motion
C.Stabilized
D.Head up

单项选择题Your ARPA has two guard zones.What is the purpose of the inner guard zone（）.

A.Alert the watch officer that a vessel is approaching the preset CPA limit
B.Warn of small targets that are initially detected closer than the outer guard zone
C.Guard against target loss during critical maneuvering situations
D.Sound an alarm for targets first detected within the zone

单项选择题Your ARPA has automatic speed inputs from the log．Due to currents，the log is indicating a faster speed than the speed over the ground.What should you expect under these circumstances（）.

A.The generated CPA will be less than the actual CPA
B.The generated TCPA will be later than the actual TCPA
C.The range of initial target acquisition will be less than normal
D.The targets true course vector will be in error

单项选择题Your ARPA has been tracking a target and has generated the targets course and speed.The radar did not receive a target echo on its last two scans due to the weather.What should you expect under these circumstances（）.

A.The ARPA will generate data as if the target was still being tracked by radar
B.The ARPA will give an audible and/or visual lost target alarm
C.The ARPA will generate data based on sea return echoes from the vicinity where the target was lost
D.The ARPA has lost all memory of the target and must recompute the target data

单项选择题The development of（）led to the fully automatic ARPA systems installed on commercial ships.

A.SeaTalk
B.powerful microprocessors and mega memory capacity
C.chartplotter
D.small-scale chart