3a Flashcards
The principle of INS is what?
Measurement of acceleration
Designed to determine the geographical position of a vehicle and to guide the vehicle from one point to another
INS Theory
The INS establishes a ____ frame of reference and senses a/c
3D
What law of motion is-
For every action there is an equal and opposite reaction
3rd
Objects tend to maintain a state of motion
1st Law
Acceleration is dependent on an objects mass and the force applied to it is what law?
2nd
This is the resistance of an object to a change in its state of motion
Inertia
This is an older system and uses mechanical gyros in a stabilized platform
Standard INS
This is a newer system that requires fewer components, provides greater speed and enhanced accuracy
Strap down RLG
Purpose is to sense acceleration in a linear direction
Accelerometers
This is an electro mechanical device that will measure acceleration forces
Accelerometer
This is a type of accelerometer which produces an electric charge when a force is exerted by the seismic mass under some accelerations
Piezoelectric
This is a type of accelerometer, acceleration causes a seismic mass pendulum to move
Servo
This is the type of accelerometer, acceleration causes a change in the space between the moving and fixed electrodes of a capacitive accelerometer
Capacitive 
Mechanically establishes a stable platform that remains orientated with the earths gravitational field
There are 4 of these 
Gimbals
This type of Gyro has a minimum start time with attitude available instantaneously upon start
Ring laser Gyro RLG
Process of precisely determining the INU attitude
Alignment
There are three types of alignment-

Optical alignment, leveling and what else
Gyro – compassing
Calibration is done where
Factory
Acceleration with time =
Velocity
Velocity with time=
Distance
The amount of drift that an INU has a incurred over a period of time
Radial error rate RER
This is the angular tilt of the platform inducing velocity errors
Drift
A medium accuracy INS has an allowable RER tolerance of what
1.6 NM/Hr
The standard INS has how many accelerometers mounted on the stabilized platform?
3
How many RLG‘s are mounted on a rigid platform
3
This has two counter rotating laser beams that travel around a closed circuit
Ring Laser Gyro RLG
There are three known INS inputs, What are they?
Present position to include aircraft altitude
Acceleration in three axis’
Time
This requires latitude, longitude and altitude while the aircraft is not moving. This gives the system a start point
Inertial data
