See list belowJUN 21 196868-PA-T-134APA/Chief, Apollo Data Priority CoordinationRequest to check some IMU alignment equations
The “D” mission flight crew has developed in detail the technique for aligning the LM platform while docked to the CSM which utilizes our knowledge of the relative alignment of the Nav bases on the CSM and LM. Part of the procedure is to establish the required LM IMU gimbal angles to be input into the LGC based on gimbal angles read- out of the CMC and the docking index reading. Rusty Schweickart derived the following equations for this purpose.
1. The formula used for docked alignment with identical REFSMMATS is:
CGALM = (300 -Δ⌀) – CGACM IGALM = IGACM + 180 MGALM = -MGACM
Where Δ⌀ is the docking ring angle.
2. The formula used for docked alignment where the stable members are oriented:
X̄LM = -Z̄CM ȲLM = ȲCM Z̄LM = X̄CM
CGALM = (300 -Δ⌀) – CGACM IGALM = IGACM + 90 MGALM = MGACM = 0
This is a special case formula only valid where the CM MGA = 0. This set of equations will be used for the LM alignment prior to undocking.
We would very much appreciate it if you would have someone in your organization check these equations to assure they are current and to report the results of their verification at our next “D” Rendezvous Mission Techniques meeting, currently scheduled for July 12 in Room 378 of Building 4.