A - IRS (14-06-18)

Question 1

What is used to calculate latitude in an IRS?

Answer 1

Apparent drift

Question 2

How many IRSs do short range A/C have?

Answer 2

2

Question 3

How many IRSs do long range A/C have?

Answer 3

3

Question 4

How do ring laser gyros work?

Answer 4

2 lasers are sent around a triangular track in opposite directions and they end up at a light detector.

They are manipulated so that they reach the light detector in phase and create a particular interference pattern

When the system is rotated one laser travels a slightly different distance to the other and therefore a phase shift occurs, changing the interference pattern and thus can be measured.

Question 5

How are random drift errors of an IRS improved?

Answer 5

Increasing the path length of ring laser gyros

Question 6

What is the accuracy of an ADIRS?

Answer 6

+/- 1m

Question 7

How is laser lock in RLGs prevented?

Answer 7

By using a dithering motor, which essentially vibrates the waves out of phase.

Question 8

How does an ADIRS combine the benefits of the air data and inertial data systems?

Answer 8

It combines the short term accuracy of the inertial data with the long term accuracy of the air data