A.Blind sectors
B.Sheltered area
C.Unseen area
D.Unscanable area
您可能感興趣的試卷
你可能感興趣的試題
A.Their bearing is almost constant，even when the true bearing of the contact changes appreciably
B.They always appear on a bearing of 90°from the true bearing of the contact
C.The indirect echoes usually appear in shadow sectors
D.When plotted，their movements are usually abnormal
A.radio signals reflect from a solid surface
B.sound waves travel at a constant speed through water
C.radar signals travel at a constant speed through water
D.pressure increases with depth
A.Water temperature
B.Climatology data
C.Speed of advance
D.Depth contours
A.Soundings
B.Waypoints
C.Meteorological data
D.Radar targets
A.Radar targets
B.ARPA vectors
C.Hydrographic data
D.All of the above
最新試題
AREAS WHICH CANNOT BE SCANNED BY THE RADAR OF THE VESSEL BECAUSE THEY ARE SHIELDED BY PARTS OF ITS SUPERSTRUCTURE，MASTS，ETC means（）.
What will NOT induce errors into a doppler sonar log?（）
A radar display in which North is always at the top of the screen is a(n)（）.
Gyrocompass repeaters reproduce the indications of the master gyrocompass. They are（）.
An electronic depth finder operates on the principle that（）.
The radar component that produces the synchronizing signal and triggers the indicator sweep is which of the following?（）.
Compass error is equal to the（）.
A radar contact will remain stationary on a relative motion radar display only when it is（）.
An ECDIS is required to display which information?（）
The number of pulses of energy transmitted per second is call the（）.