 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] M. BEIMS           ]    PASS PROGRAM NOTE        ]     17176    *   ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  JULY 1987 ]
 ] IBM/282-8662       ]      RELEASE NOTE( )        ] REV C: 12/03/91  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI8D AND SUBS                 ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW ( )  GNC (X)  VU ( )  SM/PL ( )] G9                              ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA:  IMU                                             ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: V4.10, V4.9A                                   ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] FSW STORAGE OF IMU PAIR DATA                                        ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:  * 25221                                               ]
 ] THE WAY SEVERAL VARIABLES RELATING TO IMU PAIRS ARE BEING STORED    ]
 ] IN THE FSW CAN LEAD TO MISINTERPRETATION OF DOWNLISTED DATA AND     ]
 ] ERRORS IN MATCHING I-LOADS TO THE ACTUAL IMU HARDWARE.              ]
 ]                                                                     ]
 ] THE IMU RELATIVE ATTITUDE ERROR VECTORS (CGMS_MB, V99U3551C         ]
 ] THROUGH V99U3559C) ARE STORED INTO THE ROWS OF A 3X3 MATRIX         ]
 ] DIFFERENTLY DEPENDING ON THE NUMBER OF SELECTED IMU'S IN THE        ]
 ] OPERATE MODE. WHEN THREE IMU'S ARE SELECTED, ROW 1 (V99U3551C       ]
 ] THROUGH V99U3553C) REPRESENTS THE ERROR BETWEEN IMU'S 1 AND 2,      ]
 ] ROW 2 (V99U3554C THROUGH V99U3556C) REPRESENTS THE ERROR BETWEEN    ]
 ] IMU'S 1 AND 3, AND ROW 3 (V99U3557C THROUGH V99U3559C) REPRESENTS   ]
 ] THE ERROR BETWEEN IMU'S 2 AND 3. WHEN ONLY TWO IMU'S ARE            ]
 ] SELECTED AND IN THE OPERATE MODE, THEN THE FIRST ROW (V99U3551C     ]
 ] THROUGH V99U3553C) REPRESENTS THE ERROR BETWEEN THESE TWO IMU'S;    ]
 ] THE OTHER TWO ROWS ARE MEANINGLESS. HANGAR CAL C STORES DATA        ]
 ] INTO CGMS_MB IN THIS FASHION.                                       ]
 ]                                                                     ]
 ]                                                                     ]
 ] THE IMU RELATIVE TILT/AZIMUTH ERROR VECTORS (CGMV_ENWU, V99U3285C   ]
 ] THROUGH V99U3293C), RELATIVE MISALIGNMENT VECTORS (CGMV_PHI,        ]
 ] V99U3571C THROGUH V99U3579C) AND RELATIVE MISALIGNMENT RATE VEC-    ]
 ] TORS (CGMV_PHID, V99U3581C THROUGH V99U3589C) ARE STORED IN THE     ]
 ] SAME WAY.   WHEN ONLY ONE OPERATING IMU PAIR IS SELECTED FOR AN     ]
 ] IMU SUBMODE, THE RELATIVE TILT/AZIMUTH ERROR, MISALIGNMENT AND      ]
 ] MISALIGNMENT RATE DATA FOR THAT PAIR WILL BE PACKED INTO THE FIRST  ]
 ] ROW OF EACH OF THESE MATRICES (V99U3288C, V99U3291C, AND V99U3285C, ]
 ] V99U3571C THROUGH V99U3573C AND V99U3581C THROUGH V99U3583C).       ]
 ]                                                                     ]
 ] THE GYROCOMPASS FAIL FLAGS ARE PACKED IN A THREE BIT STRING         ]
 ] CALLED CGMB_GC_FAILED. WHEN THREE OPERATING IMU'S ARE SELECTED      ]
 ] FOR ALIGNMENT, BIT 13 (V99U3262C) REPRESENTS IMU PAIR 1 AND 2;      ]
 ] BIT 14 (V99U3263C) REPRESENTS PAIR 1 AND 3; AND BIT 15              ]
 ] (V99U3264C) REPRESENTS PAIR 2 AND 3.  WHEN TWO IMU'S ARE SELECTED   ]
 ]_____________________________________________________________________]
 @



 +_____________________________________________________________________
 ]                                                                     ]
 ]                       SUPPLEMENTAL SHEET                            ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] M. BEIMS           ]    PASS PROGRAM NOTE        ]     17176    *   ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  JULY 1987 ]
 ] IBM/282-8662       ]      RELEASE NOTE ( )       ] REV C: 12/03/91  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ] FSW STORAGE OF IMU PAIR DATA                                        ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] FOR ALIGNMENT, THERE IS ONLY ONE IMU PAIR, AND BIT 13 (V99U3262C)   ]
 ] REPRESENTS THIS PAIR, WHETHER THE PAIR IS 1 AND 2, 1 AND 3, OR 2    ]
 ] AND 3.  WHEN ONE IMU IS SELECTED FOR ALIGNMENT, THERE ARE NO IMU    ]
 ] PAIRS, AND THE GYROCOMPASS GOODNESS TEST IS NOT PERFORMED.          ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ]                                                                     ]
 ] SELECTION OF WIDE VERTICAL GYROCOMPASS GOODNESS TEST LIMIT I-LOADS  ]
 ] FOR STS-26 AND SUBSEQUENT FSW ACCOMODATES ZERO MB VALUES FOR ALL    ]
 ] LRU CONFIGURATIONS.  FOR OI8D AND SUBSEQUENT FSW THE MB TERMS ARE   ]
 ] NOT USED IN THE GYROCOMPASS GOODNESS TEST.  RELATIVE ATTITUDE ERROR ]
 ] COMPENSATION IS A GROUND FUNCTION WHEN PERFORMING LAUNCH DAY CHECKS ]
 ] OF THE DOWNLISTED IMU TO IMU MISALIGNMENTS.  ALSO, POOR REPEATABI-  ]
 ] LITY OF HANGAR CALIBRATION C RESULTS LIMITS OPERATIONAL USE OF THE  ]
 ] HANG-CAL C IMU SOP SUBMODE TO TEST PURPOSES ONLY.                   ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ] CARE SHOULD BE TAKEN IN INTERPRETING DOWNLISTED VALUES FOR CGMS_MB, ]
 ] CGMV_ENWU, CGMV_PHI, CGMV_PHID, AND CGMB_GC_FAILED.  WHEN TWO IMU'S ]
 ] ARE SELECTED FOR A SUBMODE, ONLY THE FIRST ROWS OF CGMS_MB, CGMV_   ]
 ] ENWU, CGMB_PHI AND CGMV_PHID AND BIT 13 OF CGMB_GC_FAILED HAVE ANY  ]
 ] SIGNIFICANCE.  WHEN ONE IMU IS SELECTED, NONE OF THE ELEMENTS OF    ]
 ] THESE VARIABLES HAS ANY SIGNIFICANCE.                               ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM: PATTI A. THORNTON    DATE 01/21/92]                             ]
 ]    --------------------      ---------]                             ]
 ]FDSD: ROBERT N. HINSON    DATE 01/21/92]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 01/22/92 ]
 ]PF MGR:JOSEPH THIBODEAU   DATE 01/22/92]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
 @
 DR25048
