Chapter 9: Radionavigation

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Chapter 9 Radionavigation

• Instructor Fred Williston

All Questions are important for exam
PowerPoint Presentation by Forrest Meiere
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S9-1. The absolute accuracy of Loran-C is between
___ and ____ nautical miles.
0.1
0.25
S9-2. The components of the Loran-C system
include ___________________________ and
_______________
an onboard navigation receiver a chain of
three to five land-based transmitting stations.
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S9-3. Using Loran-C, position is determined as
the intersection of ______________________________
_
two or more lines of
position based on the TDs.
S9-4. Loran-C LOPs are not printed on most harbor
charts because ___________________________________
______
the corrections for signal
propagation are more complex and variable for
near shore areas than for outlying areas.
Consequently, the possible errors may be larger.
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S9-6. The principle of operation of GP5 is based
on satellite ________.
ranging
S9-8. The stated accuracy of the GPS under S/A
(95 of the time) is _____________________.
100 meters horizontally
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S9-9. A system of improved accuracy based upon
additional corrections to GP5 is termed
_______________. The horizontal accuracy of this
system is approximately _________.
Differential GPS
10 meters
S9-10. To ensure best accuracy for GPS receivers
it is important to set the _______________ to the
same as that used on the nautical chart.
horizontal datum
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S9-11. A waypoint is an imaginary point that can
be ______ in the navigation receiver.
stored

the closest distance of the
aircraft or vessel to its intended track
S9-12. The cross-track error is defined as
__________ _______________________________________
______.
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S9-13. An arrival alarm warns the mariner when
__________________________________________
the vessel or aircraft passes within a
user-defined distance of a destination waypoint.
S9-14. The modem radar display screen is known as
a ____________________.
Plan Position Indicator
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S9-15. The two principal uses for radar aboard
ships are __________ and __________________.
Navigation Collision Avoidance
S9-16. Rule 7 of the NA VRULE5 states that "
______ use shall be made of radar equipment if
fitted and operational, including long-range
scanning to obtain early warning of risk of
collision and _____________ or equivalent
systematic observation of detected objects."
Proper
radar plotting
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S9-17. Two major radar display types
are ______________ and _________.
Ships head up North up
S9-18. To increase the accuracy of range
estimates, most radar units are also equipped
with one or more ________ _____________.

variable range markers
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S9-19. To increase the accuracy with which
relative bearings can be read, most modem radar
units have one or more ___________________________
________
electronic bearing markers or
electronic bearing lines.
S9-20. A CBDR target is one that exhibits
________ _______ and ________________
presents a risk of collision.

constant bearing
decreasing range
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closest point of approach
S9-21. CPA stands for the ______________________
and provides a possible indication of collision
risk.
S9-22. The relative motion plot is used to
determine the following quantities
_________________________. _____________________
and ____________________
direction of
relative motion closest point of approach
time to the closest point of approach.
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S9-23. The vector diagram is used to determine
the target's ______ and _____.
course speed
S9-25. ARPA is an acronym for ________________

Automatic Radar Plotting Aid.
End of Questions