GPS & Electronic Navigation Aids

Question 1

What does GPS Stand

Answer 1

Global Positioning System

Question 2

What does GNSS stand for?

Answer 2

Global Navigation Satellite System

Question 3

What does AIS stand for?

Answer 3

Automated Identification System

Question 4

How does AIS work?

Answer 4

A vessel transmits data on itself via VHF and GPS and then this information is displayed on a screen

Question 5

Name three pieces of information you could find on a vessel on an AIS display?

Answer 5

Name, Callsign, Status, Destination, Type, Speed/Direction, Size, Received

Question 6

How does Radar work?

Answer 6

Radar sends out a rotating beam of radio frequency waves and captures the echoes back then displays them on a screen

Question 7

Why is it better to have the aerial mounted as low as possible on the vessel?

Answer 7

The signal strengths are quite week in GPS

Question 8

True or False?
You should ensure your GPS in on the same datum as your chart

Answer 8

True

Question 9

What is a waypoint?

Answer 9

Any spot on a chart that you want to use for navigation

Question 10

What is the symbol for a waypoint?

Answer 10

A square and a cross combined

Question 11

True or False?
You can string a series of waypoints together to define a route

Answer 11

True

Question 12

What is the Cross Track Error (XTE)?

Answer 12

It tells us how far off course we are

Question 13

What are the two ways in which I can use XTE to stay on course?

Answer 13

XTE Alarm
XTE Ladder

Question 14

When would GPS Web be useful?

Answer 14

High speed navigation

Question 15

What does GPS stand for

Answer 15

Global Positioning system

Question 16

what are the 3 elements of a gps system

Answer 16

the satellites transmitting position information, ground stations controlling the satellites, and a personal receiver, which collects and computes the location

Question 17

how many satellites are required for an accurate fix

Answer 17

4 satilties

Question 18

how does gps work out location

Answer 18

by taking the time a signal takes to reach your receiver and the speed of light it gives the distance from the satellite. adding 4 more satellites narrows this down to a single location in 3d space

Question 19

How do gps calculate speed

Answer 19

by comparing two fixes distance, and mesuring the time between fixes

Question 20

what is the hdcp

Answer 20

horizontal dilution of precision

Question 21

do you want to have a high or low HDCP to get a good gps fix

Answer 21

a low HDCP

Question 22

what should you do before using a waypoint from a pilot guide with a GPS

Answer 22

plot the waypoint on a chart to ensure it is what it says it is.

Question 23

what is the SOG

Answer 23

Speed overground

Question 24

what is the TTG

Answer 24

time to go, estimated time before arrival at next waypoint

Question 25

what is the XTE

Answer 25

cross-track error

Question 26

what is the COG

Answer 26

Course overground

Question 27

what is the VMG

Answer 27

Velocity Made Good

Question 28

What is the cross-track error used for

Answer 28

the cross-track error is used for alerting the skipper if the vessel is outside of a certain margin of error from the planned course.

Question 29

what is the vilocity made good

Answer 29

the speed along the course, taking account for tacking or not going straight towards it

Question 30

to comply with maritime law, what cant you use a gps for

Answer 30

as a primary means of navigation