单项选择题
A.Satellite clock B.Ship's speed C.Atmospheric/ionospheric propagation D.Receiver
To obtain accuracy in fixing by DF，（）and three stations...
单项选择题To obtain accuracy in fixing by DF，（）and three stations should be used.
A.Parallel bearings B.Long-range bearings C.Short-range bearings D.Cross bearings
The use of pulse groups and extremely precise timing at...
单项选择题The use of pulse groups and extremely precise timing at each Loran-C station makes possible the use of（）.
A.High frequency pulses B.Combinations of high and low frequency pulses C.The same frequency for all stations in a chain D.Varied long and short pulses
The time interval between the transmission of signals f...
单项选择题The time interval between the transmission of signals from a pair of Loran-C stations is very closely controlled and operates with（）.
A.An atomic time standard B.Daylight Savings Time C.Eastern Standard Time D.Greenwich Mean Time
