Inertial Navigation | Schuler Tuning Flashcards
With the INS not moving, it assumes that it is ___. This is a form of error and must be removed from the calculations to ensure that it actually measures __
falling towards the centre of the Earth, zero
The time taken to go from one extreme to the other is the Schuler period of __ minutes
84.4
A system with an identical period would indicate the local ___, regardless of any acceleration of a vehicle carrying it
vertical
An INS platform behaves just like an Earth pendulum in that, when it is disturbed, it takes ___ minutes to settle down again.
84.4
The ___ wobbles, rather than the INS even though it appears to when seen relative to the Earth
Earth
The relationship between a circle’s angle in radians and its circumference is ___
1/R
Multiplying 1/R by V gives the angular velocity over a surface distance, or the ___ ___, which is used to torque the gyro and make the platform precess at the same rate that it is being moved over the Earth’s surface
transport rate
Schuler tuning prevents the accumulation of errors which would be caused by ___ ___ and treating ___ as an acceleration
platform tilt, gravity
Schuler tuning will not compensate for errors from the precession of the ___ ___
steering gyro
Schuler tuning provides an dampened closed-loop corrective action to stop tilt errors, oscillating around a zero value over __ minutes
84.4
The Schuler tuned platform maximises its error at ___ and ___ minutes through each cycle
21.1 63.3
The magnitude of the maximum error depends on the size of the disturbance that caused it, but the mean error remains at ____
zero
Any errors in the output of the accelerometers caused by Schuler tuning is ___
bounded
The output of the ___ indicator will be bounded
first
___ ___ systems are considered to be Schuler tuned, and to suffer similar bounded errors
Strapped down
You cannot use the system until the platform is levelled and the system is aligned with __ __, called ___
True North, gyrocompassing
Gyrcompassing is completed by motoring the level platform until there is no topple output from the ___ gyro
East
After having been gyrocompassed, the topple output of the North Gyroshoule equal the ___ ___, which is __ x ___
Earth Rate 15 x Cos( Latitude )
Gyrocompassing is ____ at high latitudes as a result of the high torque rates
impossible
With coarse levelling, the __ and ___ gimbals are driven until they are at __ degrees to each other.
pitch roll 90
The platform is levelled to __ degrees against the aircraft frame or gravity, using the horizontal accelerometers or gravity switches
10
Coarse azimuth is achieved by turning the platform in azimuth until the heading output agrees with the ___ ___ ___ ___
aircraft best known heading
Coarse azimuth is followed by ___ levelling, which is done by motoring the platform until no acceleration from gravity is sensed by the _ and _ accelerometers
fine x y
___ levelling uses the accelerometer null technique, with the aircraft stationary there shuold be no output from the horizontal accelerometers if the platform is level
Fine
