(2)
Platform stabilization is achieved by use of two 2 degrees of freedom gyros mounted on the platform in the al1-attitude gimbal system. The gyros are mounted with their sense (input) axes mutually perpendicular. Any minute tilt or rotation of the platform produces an input torque about the sense axis of one or more of the gyros. This causes induced gyroscopic precession which causes the gyro gimbal to rotate about the gyro output axis and generate an output signal from the gyro pickoff which is representative of the angular displacement of the gimbal. This signal is amplified and used to drive the platform gimbal torquer through a corresponding angle of rotation to maintain the gyro output at a null, and thus maintain correct platform orientation.
(3)
Stabilization of the inertial platform allows a fixed coordinate system to be established within which airplane accelerations can be measured. This is accomplished by two accelerometers, mounted on the stable platform with their sense axes mutually perpendicular and aligned with reference axes on the platform. The accelerometers sense airplane translational motion and are maintained parallel to the earth's surface.
E. Computer
(1) The inertial navigation problem uses continuously changing navigation parameters and repeatable system error factors to obtain a high degree of accuracy in the attitude and heading computations. For this reason a computer is used as the information processing center for the inertial navigation system. The computer:
(a)
solves mechanization equations associated with great circle navigation
(b)
supplies control information to the inertial platform to keep it earth referenced
(c)
supplies digital information to various INS and interface components in order to display system status and navigation parameters.
(d)
monitors its own operation and that of other INS components
(e)
supplies guidance signals to the autopilot to steer the airplane along a great circle path
EFFECTIVITY AIRPLANES WITH LTN-72 INS
CONFIG 01 A Page 16 Apr 25/86
34-41-00
Selector System
Position Mode
TK/GS NAV
HDG/DA NAV
XTK/TKE NAV
POS STBY
ALIGN
NAV
Left Display
Displays track angle with respect to true north from 0 to 359.9 degrees, in 0.1-degree increments when ground speed is greater than 10 knots. Below 10 knots, true heading is displayed.
Displays aircraft heading with respect to true north from 0 to 359.9 degrees in 0.1-degree increments.
Displays airplane cross-track distance left or right of the desired track from 0 to 399.9 NM in 0.1-NM incre-ments. Cross-track distance is available when initial track is established.
If REMOTE (RMT) is selected, reads inserted value of cross-track offset desired relative to track leg shown in FROM/TO display.
Displays airplane present position latitude north or south from 0 to 90 degrees 00 minutes in 0.1-minute increments.
Right Display
Displays ground speed from 0 to 3999 NM/hour in 1.0-NM/ hour increments when ground speed is greater than 1 knot.
Displays drift angle (differ-ence angle in degrees that airplane track angle is to the left or right of airplane heading) from 0 to 180.0 degrees in 0.1-degree incre-ments. Drift angle is available when ground speed is above 10 knots; below 10 knots drift angle reads 00.0.
Displays track angle error (difference between actual track angle and desired track angle) left or right from 0 to 180.0 degrees in 0.1-degree increments. Track angle error is available when initial track is established.
Displays airplane present position longitude east or west from 0 to 180 degrees 00 minutes in 0.1-minute increments.
Control/Display Unit Display Outputs
Figure 9 (Sheet 1)
EFFECTIVITY
CONFIG 2AIRPLANES WITH LTN-72 INS
799 Page 17
34-41-00
Apr 25/86
T34605
Selector System Position Mode
WPT STBY ALIGN NAV
DIS/TIME STBY ALIGN NAV
WIND NAV Left Display
Displays latitude as in POS position of stored waypoint corresponding to digit on WPT thumbwheel.
Reads un-updated present position when HOLD pushbutton is pressed.
Displays great circle distance-to-go to the next selected waypoint from 0 to 9999 NM in 1.0-NM incre-ments. Distance is avail-able when initial track is established.
When REMOTE (RMT) is selected:
Right Display
Displays longitude as in POS position of stored waypoint corresponding to digit on WPT thumbwheel.
Reads un-updated present posi-tion when HOLD pushbutton is pressed.
Displays time-to-go to the next selected waypoint at the present ground speed and desired track from 0 to 999.9 minutes in 0.1- minute incre-ments. Time is available when initial track is established and ground speed is greater than 10 knots.
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本文鏈接地址：747飛機維護手冊AMM CHAPTER 34 - NAVIGATION 第34章導航2(110)
