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Flashcards in ET VOL 5 Ch 1 Deck (62)
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1

2

Tactical navigation is directly concerned with maneuvering the ship in navigable waters.

false

3

Estimating ship’s position between known navigational points or fixes is known as

dead reckoning

4

Radio navigation consists of which of the following categories?

1. Sub-space systems (SATNAV, TRANSIT, NAVSTAR) 2. Space–based systems (omega, loran)

5

One of the characteristics of dead reckoning is that the accuracy of the estimated position never exceeds the navigation method used to obtain the last fix. What happens to the accuracy of the estimated position over time?

It fluctuates

6

Referring to landmarks with known positions on earth describes which one of the following navigation methods?

piloting

7

Which of the following actions required to determine position in piloting is/are not required in electronic navigation?

Seeing the landmarks

8

According to the 1992 Federal Radio Navigation Plan, which of the following systems will become the primary reference navigation system for surface ships?

NAVSTAR(GPS)

9

what is LORAN

Long Range Aid to NAvigation

10

What is omega

VLF radio NAvigation

11

LORAN takes advantage of what radio signal characteristic?

Constant velocity

12

OMEGA is a hyperbolic phase— difference measuring system that compares the phase angle of two or more radio signals synchronized to what device or factor?

A common time base

13

Which navigation system continually computes the latitude and longitude of a ship by sensing acceleration?

SINS (Ships inertial navigation system)

14

A ship’s inertial navigation system is dependent on celestial, sight, and radio navigation aids.

false

15

What device measures changes in speed or direction along the axis in which it lies?

Accelerometer

16

What type of system is used to keep a SINS platform stabilized?

Gyro

17

Which of the following is a standalone SINS?

AN/WSN-5

18

Approximately how often can operators using the NNSS obtain fixes?

Every 2 hours

19

NNSS satellites transmit phase modulated data every 2 minutes on how many rf carriers?

2

20

What are the two types of NNSS satellite parameters included in the phase-modulated data?

Fixed and variable

21

The nominal orbit of NNSS satellites is what type of orbital parameter?

fixed

22

NNSS satellite data can be used as an accurate time reference.

true

23

NNSS satellite refined orbits are calculated at which of the following facilities?

Tracking station

24

Which of the following facilities calculates NNSS satellite clock error before satellite message injection?

Control center

25

Approximately how long does it take the injection station to transmit information to an NNSS satellite?

15 seconds

26

If errors are detected during a readback of freshly injected satellite data, how often is NNSS satellite message injection repeated until the transmission is verified as being correct?

every 2 minutes

27

At what point during the satellite pass will expansion effects cause the received frequencies to drop below the generated frequencies?

T3- Leaving away from

28

At what point will the received frequencies exactly match the transmitted frequencies?

T2-EVEN

29

At what point will compression effects cause the received frequencies to be higher than the transmitted frequencies?

T1- Approaching Fast

30

Which of the following factors affects the measurement of Doppler shift?

Refraction