Gyro Compass (MIDTERM AND FINALS)

Question 1

a non magnetic compass in which the direction of true north is maintained by a continuously driven gyroscope whose axis is parallel to the earth’s axis of rotation

Answer 1

gyro compass

Question 2

consists of a spinning wheel or rotor contained within gimbals which permit movement about three mutually perpendicular axes, known as the horizontal axis, the vertical axis, and the spin axis

Answer 2

gyroscope

Question 3

two basic properties of gyroscopes

Answer 3

Rigidity and Precession

Question 4

The axis of rotation (spin axis) of the gyro wheel tends to remain in a fixed direction in space if no force is applied to it.(gyroscopic inertia)

Answer 4

RIGIDITY

Question 5

depends on the angular velocity, mass, and radius of the wheel or rotor

Answer 5

Gyroscopic inertia

Question 6

The axis of rotation has a tendency to turn at a right angle to the direction of an applied force

Answer 6

PRECESSION

Question 7

the rate of precession is proportional to the

Answer 7

applied torque

Question 8

a change in the orientation of the rotational axis of a rotating body

Answer 8

PRECISSION

Question 9

This phenomenon is found only in spinning bodies. It is the movement of the spin axis when a force is applied to the spin axis of gyroscope. When a couple is applied about its horizontal axis, the spin axis will turn at right angles to the applied force in the direction of the spin of the wheel. Similarly couple applied about the vertical axis will make the spin axis turn about the horizontal axis in the direction of the spin axis of the wheel

Answer 9

PRECESSION

Question 10

If the applied torque has a component which is perpendicular to the initial angular momentum the gyroscope will

Answer 10

PRECESS

Question 11

is a measure of how much a force acting on an object causes that object to rotate

Answer 11

Torque

Question 12

three vectors

Answer 12

torque, spin, and precession

Question 13

are all oriented with respect to each other according to the right-hand rule

Answer 13

three vectors, (torque, spin, and precession)

Question 14

It has 3 degrees of freedom:

Answer 14

1. It is free to spin about spinning axis
2. It is free to rotate about vertical axis
3. It is free to rotate about horizontal axis

Question 15

The motion of the spin axis in the horizontal plane is known as

Answer 15

drift

Question 16

The movement of spin axis in the direction of Azimuth is

Answer 16

drift

Question 17

The rate of change of drift is

Answer 17

drifting

Question 18

The motion of spin axis in the vertical plane is known as

Answer 18

tilt

Question 19

The angle of elevation or depression of the spin axis above or below the horizontal is

Answer 19

tilt

Question 20

The rate of change of tilt is

Answer 20

tilting

Question 21

The gyrocompass depends upon four natural phenomena:

Answer 21

gyroscopic inertia, precession, earth’s rotation, and gravity

Question 22

To make a gyroscope into a gyro compass, the wheel or rotor is mounted in a sphere, called the _, and the sphere is then supported in a _

Answer 22

gyro sphere, vertical ring

Question 23

The whole is mounted on a base called the

Answer 23

phantom

Question 24

The rotor may weigh as little as half a kilogram to

Answer 24

over 25 kg

Question 25

To make the gyro seek north, a system of reservoirs filled with mercury, known as _, is used to apply a force against the spin axis

Answer 25

mercury ballistics

Question 26

used to apply a force against the spin axis

Answer 26

mercury ballistics

Question 27

usually four in number, are placed so that their centers of gravity exactly coincide with the CG of the gyroscope

Answer 27

ballistics

Question 28

then causes the spin axis to trace an ellipse, one ellipse taking about 84 minutes to complete

Answer 28

Precession

Question 29

To make it seek and maintain true north, three things are necessary.

Answer 29

First, the gyro must be made to stay on the plane of the meridian. *Second, it must be made to remain horizontal. *Third, it must stay in this position once it reaches it regardless of what the vessel on which it is mounted does or where it goes on the earth

Question 30

one ellipse taking about _ to complete

Answer 30

84 minutes

Question 31

two methods of damping:

Answer 31

Damping in tilt and Damping in azimuth

Question 32

In this method a force is applied in the horizontal plane (a torque to the vertical axis) which results in a precession in the vertical plane, reducing the

Answer 32

Damping in tilt

Question 33

In this method a precession is developed which assists the movement in the azimuth plane when the axis moves towards the meridian, and opposes the movement when the spin axis moves away from the meridian

Answer 33

Damping in azimuth

Question 34

means that when the North-seeking end of the gyroscope axis is - a damping torque is applied in a horizontal plane in such a direction that the resultant precession in a vertical plane causes the - of the axis to decrease

Answer 34

Damping in tilt

Question 35

The amplitude of each oscillation is reduced to _ and thereby resulting in the axis finally setting down in the meridian

Answer 35

1/3 of the previous oscillation

Question 36

is achieved by introducing a torque in a vertical plane, which causes a precession opposite to the gravity control precession but out of phase with it, i.e, with a time delay.

Answer 36

Damping in azimuth

Question 37

The _ causes the axis to overshoot the meridian less each time it crosses it until the gyroscope axis reaches its setting position

Answer 37

resultant precession in a horizontal plane

Question 38

is a very important and unique tool in marine navigation as it does not operate automatically like other magnetic compasses

Answer 38

Fluxgate compass

Question 39

is an electromagnetic compass which solves the purpose of a conventional compass

Answer 39

fluxgate compass

Question 40

is a device that helps to correctly pinpoint the geographical direction while on a sea going vessel

Answer 40

compass

Question 41

is a very important and unique tool in marine navigation as it does not operate automatically like other magnetic compasses

Answer 41

fluxgate compass

Question 42

is an electromagnetic compass which solves the purpose of a conventional compass

Answer 42

fluxgate compass

Question 43

is used in ships mainly for the purpose of steering.

Answer 43

fluxgate compass

Question 44

the compass is an electronic one, the scope of errors is greatly reduced. In addition to manual steering, such a compass can also be utilised when the ship is on autopilot. Even chart plotters and radars use this system to provide them with accurate geographic indications

Answer 44

fluxgate compass

Question 45

there are no pointers that specify the direction

Answer 45

electronic compass

Question 46

There are two coils of wire that are located perpendicular to each other around a permeable magnetic material. When electric current is passed through the coils the core material works an electromagnet and senses the direction of the horizontal component of the earth’s magnetic field. This completely eradicates the problem caused due to the interference of the magnetic north is completely avoided

Answer 46

electronic compass

Question 47

Another advantage of installing this type of compass in the ship is that these types of compasses are unaffected by their placement on the ship.

Answer 47

electronic compass

Question 48

They can be placed anywhere and the directions pointed by the compass can be relied on completely.

Answer 48

electronic compass

Question 49

can prove very useful during rough seas as they are unaffected by position and unusual movements

Answer 49

Fluxgate compass

Question 50

is one of the best navigating technologies that are available in the marine industry

Answer 50

fluxgate compass

Question 51

which detects and transmits the ship's Compass Heading over a digital connection to one or more CompassHeading Repeaters at any convenient location on a vessel.

Answer 51

Transmitting Magnetic Compass (TMC) System

Question 52

provides a complete alternative (or a backup) to a gyro compass as a source of Heading.Magnetic Variation andDeviation can be corrected using theMarine Data to give True Heading.

Answer 52

TMC system

Question 53

can provide a source of Heading for Compass Repeaters and other navigation equipment.

Answer 53

TMC

Question 54

refers to electronic components, devices, and systems based entirely on the semiconductor

Answer 54

Solid-state

Question 55

The expression was especially prevalent in the late 1950s and early 1960s, during the transition from vacuum tube technology to the semiconductor diode and transistor

Answer 55

Solid-state