Alignment procedures for the Gyro Display Coupler (GDC)

Content

  1. GDC alignment using the DSKY

  2. GDC alignment using the IMU



1.GDC alignment using the DSKY



Based on ref.xxxx

Based on ref.xxxx
Figure 1.1

  1. Set the FDAI SRC switch to ATT SET and the ATT SET switch to GDC
    On the FDAI, the error needles will display the difference between the GDC attitude readings and the ACSP attitude readings set by its dial switches.
  2. Take the readings of the three attitude angles from the DSKY and enter them into the ASCP using the dial switches.
    The erroer readings on the FDAI will change and will reflect the difference between the GDC and the IMU attitude readings.
Figure 1.2

  1. Press the GDC ALIGN switch to equalize the GDC with the ASCP
    On the FDAI, the error needles which display the difference between the GDC and the ACSP attitude readings will be set to zero.
    The GDC is now aligned with the IMU.



2.GDC alignment using the IMU



Based on ref.xxxx

Based on ref.xxxx
Figure 2.1

  1. Set the FDAI SRC switch to ATT SET and the ATT SET switch to IMU.
    On the FDAI, the error needles will display the difference between the IMU attitude readings and the ACSP attitude readings set by its dial switches.
  2. Change the dial settings of the ASCP until the FDAI error needles are set to zero.
    The dial settings of the ASCP will now reflect the IMU readings.
Figure 2.2

  1. Set the ATT SET switch to GDC.
    On the FDAI, the error needles will display the difference between the GDC attitude readings and the ACSP attitude readings set by its dial switches.


Based on ref.xxxx
Figure 2.3

  1. Press the GDC ALIGN switch to equalize the GDC with the ASCP
    On the FDAI, the error needles which display the difference between the GDC and the ACSP attitude readings will be set to zero.
    The GDC is now aligned with the IMU.



Acronyms
ASCP Attitude Set Control Panel
BMAG Body Mounted Attitude Gyro
CMC Command Module Computer
DSKY Display and Keyboard
FDAI Flight Director Attitude Indicator
GDC Gyro Display Coupler
IMU Inertial Measurement Unit

References
  1. Apollo Operations Handbook Block II Spacecraft
    Volume 1, Spacecraft Description
    Section 2
    Published under authority of NASA
    Spacecraft Systems Operation Branch
    Flight Crew Support Division
    SM2A-03-BLOCK II, 15 April 1969
    (Last change date: 15 Octobr 1969)

  2. Ref.

  3. Ref.

  4. Ref.




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