E-Nav Quiz 4 - Comprehensive Review of Navigational Terms and Concepts

The amount of gain required to obtain a fathometer reading depends upon which factor?

Type of bottom

A Doppler speed log indicates speed over ground _______.

in the bottom return mode

Which design of speed log uses a paddle wheel type device?

Impeller

What is the speed of sound in 60F sea water?

4814 ft/sec

Loran-C is what type of navigation system?

Parabolic

With respect to (AIS), which information is required to be broadcast every 1 to 10 seconds?

Time stamp.

The physical location of antenna aboard the ship.

Destination.

All of the above.

Time stamp.

How does the gyroscope become north seeking so that it can be used as a compass?

By mechanically or electrically applying forces to precess the gyroscope

Which of the following statements is TRUE regarding AIS text messaging?

AIS text messaging can be used but is not in lieu of the COLREGS meeting and passing requirements.

What can be stated about sky waves?

The sky wave night effect is greater around the time of morning and evening twilight.

A Doppler speed log indicates speed through the water ______.

in the volume reverberation mode

Which system is designed to be an effective deterrent to GPS jamming and spoofing?

eLoran

Which of the following statements is TRUE regarding automatic identification systems (AIS)?

AIS can be relied upon as the sole means to determine course and speed changes.

AIS provides near real-time information in bad weather of another vessel's SOG/COG.

AIS is designed to replace radar as a means to ascertain the risk of collision.

AIS will not provide information if a vessel is indistinguishable in radar sea clutter.

AIS provides near real-time information in bad weather of another vessel's SOG/COG.

A Class B AIS device in lieu of a Class A device is permissible on which type of vessel?

Fishing industry vessels.

What is defined as a measure of a radio beacon receivers ability to detect transmissions?

sensitivity

To whom should the person directing the movement of a vessel report the failure of the navigational equipment?

Any of the above.

AIS broadcasts all of the following information every 1 to 10 seconds EXCEPT ______.

ship's name

Which is NOT a type of AIS ATON?

Special

Which of the following statements is TRUE regarding automatic identification systems (AIS)?

Under no circumstances shall AIS be turned off while underway.

The master may turn off the AIS if the safety or security of the vessel is jeopardized.

AIS is always required to be operating if the vessel is within 100 NM of the coastline.

AIS is always required to be operating if the vessel is in or in the vicinity of a VTS area.

The master may turn off the AIS if the safety or security of the vessel is jeopardized.

Which speed log uses differential pressure to determine an object's STW?

Pitometer

Which device relies upon a frequency shift for estimating the speed of a moving body?

Doppler Log

The reaction of a gyrocompass to an applied force is known as _______.

precession

When at sea in mid-ocean, what is the traditional practice for determing Gyro error?

Take an Azimuth of the Sun at sunset or sunrise

What is another term for gyroscopic inertia?

Rigidity in space

Which of the following is NOT at type of electronic compass?

HRG

RLG

IFOG

BFS

BFS

Who invented the gyrocompass?

Anshutz Kampfe

&

Elmer Sperry

What is the difference between a gyroscope and a gyrocompass

In a gyroscope, no force is applied in order to keep it aligned to the earth rather than space

In a mechanical gyrocompass, how is the gyroscope forced to seek true north?

Through system of reservoirs filled with fluid, known as ballistics

What is the scientific basis behind the Ring Laser Gyrocompass?

Sagnac Priciple

Typical Gyrocompass errors can be as much as 1 degree off from true. If compass north is left of true north how do we correct the reading?

GET (Gyro + East = True)

When installing a Flux Gate Mangnetometer, where is the best place to locate the sensor?

High up on the ship's mast

Which of the following is NOT one of the three named axis which provides the three degrees of movement of a gyroscope?

Rotary axis

Shipborne carriage requirements for AIS are contained in SOLAS regulation _______.

Chapter V, Regulation 19

What is a Real AIS ATON?

A physical aid to navigation structure on which an AIS transmitter is affixed and from which AIS messages are broadcast.

GPS operates on which type of frequency?

UHF

Relating to GPS, what does the abreviation SPS stand for?

Standard Positioning Service

All of the the following atmospheric layers effect the accuracy of the GPS time signals. Which one causes the most difficulties during the mid-afternoon?

Ionosphere

Which country operates the QZSS regional GNSS?

Republic of Japan

The ideal GPS fix would occur with one satellite directly overhead and the three others spaced at _____ degrees around the horizon.

120

Your ARPA has two guard zones. What is the purpose of the inner guard zone?

Warn of small targets that are initially detected closer than the outer guard zone

Which ARPA data should you use in order to determine if a close quarters situation will develop with a target vessel?

Relative track information

When using an ARPA, what should you consider in order to evaluate the information displayed?

Navigational constraints may require a target vessel to change course.

With respect to automatic identification systems (AIS), which information is expected to be broadcast every 1 to 10 seconds?

.Latitude and longitude

.Navigational status

.Rate of turn

.All of the above

All of the above

What does not contribute to the commercial GPS receiver position error?

Ship's speed

The speed of sound in water is approximately __________.

4.5 times its speed in air

While underway, a vessel over 100,000 gross tons with an automatic identification systems (AIS) is expected to broadcast all of the following information every 1 to 10 seconds EXCEPT __________.

.ship's heading

.navigational status

.rate of turn

.name of vessel

name of vessel

All echo-sounders can measure the __________.

actual depth of water below keel

Time signals broadcast by WWV and WWVH are transmitted __________.

continuously throughout day

Mean lower low water is the reference plane used for __________.

soundings on the U.S. east and west coasts

A Doppler speed log indicates speed over ground __________.

in the bottom return mode

With respect to automatic identification systems (AIS), which information is expected to be broadcast every 1 to 10 seconds?

Ship's heading

Which information is NOT provided in broadcasts by the National Institute of Standards and Technology?

NAVAREA Warnings

Which feature, when set to zero, might allow a GPS unit to have an accuracy equivalent to Precise Positioning Service receiver capability?

Selective Availability

A Doppler speed log indicates speed through the water __________.

in the volume reverberation mode

When using an echo sounder in deep water, it is NOT unusual to __________.

receive a strong return at about 200 fathoms (366 meters) during the day, and one nearer the surface at night

An electronic depth finder operates on the principle that __________.

sound waves travel at a constant speed through water

When operated over a muddy bottom, a fathometer may indicate __________.

two depth readings

With respect to automatic identification systems (AIS), which information is required to be broadcast every 1 to 10 seconds?

a.Call sign and IMO number

b.MMSI number and call sign

c.Route Plan and navigational status

d.Course over ground and MMSI

Course over ground and MMSI

While underway, automatic identification systems (AIS) broadcast all of the following information every 1 to 10 seconds EXCEPT the __________.

a.latitude and longitude

b.ship's scantlings

c.speed over ground

d.course over ground

ship's scantlings

In modern fathometers the sonic or ultrasonic sound waves are produced electrically by means of a(n) __________.

transducer

The short text messaging feature of the automatic identification system (AIS) allows for messages of up to __________.

158 characters

Which type of GPS receiver has at least four channels to process information from several satellites simultaneously?

Continuous

The highest level of commercial navigational accuracy is provided by __________.

DGPS, within a coverage area

If a sound signal is emitted from the oscillator of a fathometer, and two seconds elapse before the returning signal is picked up, what depth of water is indicated?

824 fathoms

The recording fathometer produces a graphic record of the __________.

depth underneath the keel against a time base

What will NOT induce errors into a Doppler sonar log?

Increased draft

The speed of sound through ocean water is nearly always __________.

faster than the speed of calibration for the fathometer

What should you apply to a fathometer reading to determine the depth of water?

Add the draft of the vessel.

In general, on how many radio channels will an automatic identification system (AIS) operate?

2

Most GPS receivers use the Doppler shift of the carrier phase to compute __________.

Speed

With regard to GPS, a civilian receiver may be capable of achieving the same accuracy as a military receiver if __________.

selective availability is set to zero

A Doppler log in the volume reverberation mode indicates __________.

speed through the water

A low HDOP (Horizontal Dilution of Precision) number such as 2 indicates a __________.

good fix

With respect to failure warnings and status indications, GPS receivers should provide, at a minimum, __________.

a warning of loss of position

You are navigationing an AIS equipped vessel which is proceeding at 20 kts. When changing course, how often is the AIS dynamic data transmitted from your vessel?

every 2 seconds

What is Class B AIS?

Shipborne equipment which provides functionalities not in full accordance with IMO AIS carriage requirement.

AIS is intended to enhance _______.

safety of life at sea

the safety and efficiency of navigation

the protection of the marine environment

All the above

All the above

What is an accurate description of eNavigation as it pertains to AIS?

The distribution of electronic Maritime Safety Information (e-MSI) information though the AIS system

What is the NAIS Project?

A safety and security data collection network

AIS transits signals using the TDMA method. What does the acyronym TDMA mean?

Time Division Multiple Access

Which type of GNSS disturbance does not trigger an alarm in a typical GPS receiver and is considered a clandestine act?

Spoofing

The Duttons textbook describes one of the common psychological problems when using GNSS. Which of the following statements is most correct?

GNSS may cause the navigator to become complacent or even reckless regarding allowable proximity to hazards as compared to navigation without GPS

Vessels required to have an Automatic Radar Plotting Aid must have a device (sensor) to indicate the _______.

speed of the vessel over the ground or through the water

The clockwise rotating radar antenna has a beam width of 2°. The radar gyro bearing of the right tangent of an island is 316°. The gyro error is 1° E. Which true bearing should be plotted on the chart?

316°

You are radar scanning for a buoy fitted with a racon. In the illustration below, which radar screen represents the presentation you should expect on the PPI?

B

The clockwise rotating radar antenna has a beam width of 2°. The left tangent bearing of a small island, as observed on the PPI scope, is 056° pgc. If the gyro error is 2° E, what bearing would you plot on the chart?

059°

When using GPS without Selective Availability, you may expect your horizontal accuracy to be better than __________.

20 meters

Which of the following is NOT an active GNSS?

GALILEO

With respect to automatic identification systems (AIS), which information is required to be broadcast every 1 to 10 seconds?

a.Destination

b.Location of antenna

c.Time stamp

d.None of the above

Time stamp

When using a recording depth finder in the open ocean, what phenomena is most likely to produce a continuous trace that may not be from the actual ocean bottom?

Echoes from a deep scattering layer

Which statement concerning GPS is TRUE?

It may be suspended without warning.

Which factor has the greatest effect on the amount of gain required to obtain a fathometer reading?

Type of bottom

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?

The targets true course vector will be in error.

What will cause the ARPA to emit a visual alarm, audible alarm, or both?

A tracked target entering your preset CPA-TCPA limits

Vessels required to have an Automatic Radar Plotting Aid must have a device to indicate the __________.

speed of the vessel over the ground or through the water

When using the ARPA in heavy rain, which action should you take?

Navigate as though the effective range of the radar has been reduced.

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?

The ARPA will generate data as if the target was still being tracked by radar.

The beam width of your radar is 2°. The left tangent bearing of a small island, as observed on the PPI scope, is 056° pgc. If the gyro error is 2° E, what bearing would you plot on the chart?

059°

What is TRUE of the history display of a target's past positions on an ARPA?

In the true presentation, it provides a quick visual check to determine if a vessel has changed course.

The ARPA may swap targets when automatically tracking if two targets __________.

pass close together

Which of the following statements is TRUE regarding automatic identification systems (AIS)?

AIS provides the other vessel's identity, dimensions and navigational status regardless of visibility.