55 INS Flashcards

1
Q

INS def

A

An INS is a navigation aid that uses a computer and motion sensors (accelerometers) to continuously calculate via dead reckoning the position, orientation, and velocity (direction and speed of movement) of a moving object without the need for external references

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2
Q

Advantages of INS 6

A
  1. Self contained
  2. Does not radiate
  3. Unjammable
  4. Allweather operation
  5. Worldwide operation
  6. By its true nature, INS provides relatively accurate position and very accurate attitude information
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3
Q

Generic INS Components 4

A
  1. Accelerometers
  2. Computers (calculate data from accelerometer)
  3. Stable Platform
  4. CDU
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4
Q

Newton 1st law of motion

A

Law of inertia
A body at rest or, if already in motion, remains in uniform motion with constant speed in a straight line, unless it is acted on by an unbalanced external force

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5
Q

2nd law of motion

A

Mass is constant in any static system
Therefore a specific acceleration will result from a specific force
Must measure F to find a
The force applied to the mass is proportional to the resultant acceleration

F=ma

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6
Q

Mechanical INS

A

the original INS was a mechanical system mounted on a free moving stable platform
A stable platform uses gimbals and mechanical gyroscopes to maintain a level reference about 3 orthogonal axes for the accelerometers to sense movement

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7
Q

Strapdown INS

A

Modern INS are strapdown systems, the accelerometers and gyroscopes are mounted directly on the aircraft frame
Inputs from gyroscopes help create a computer generated transformation matrix (Quaternion or simulated stable platform) to replace the stable platform and provide a level reference for the accelerometers.
Mechanical gyroscopes have been replaced with ring laser gyroscopes.

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8
Q

Desired characteristics of accelerometers

A

1 low threshold of sensitivity
2 wide range of sensitivity
3 linear output
4 high resolution

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9
Q

Earth rate

A

15.04º/hr

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