Source Code
015173,000001: # Copyright: Public domain.
015174,000002: # Filename: GIMBAL_LOCK_AVOIDANCE.agc
015175,000003: # Purpose: Part of the source code for Luminary 1A build 099.
015176,000004: # It is part of the source code for the Lunar Module's (LM)
015177,000005: # Apollo Guidance Computer (AGC), for Apollo 11.
015178,000006: # Assembler: yaYUL
015179,000007: # Contact: Ron Burkey <info@sandroid.org>.
015180,000008: # Website: www.ibiblio.org/apollo.
015181,000009: # Pages: 364
015182,000010: # Mod history: 2009-05-17 RSB Adapted from the corresponding
015183,000011: # Luminary131 file, using page
015184,000012: # images from Luminary 1A.
015185,000013: # 2010-12-31 JL Fixed page number comment.
015186,000014:
015187,000015: # This source code has been transcribed or otherwise adapted from
015188,000016: # digitized images of a hardcopy from the MIT Museum. The digitization
015189,000017: # was performed by Paul Fjeld, and arranged for by Deborah Douglas of
015190,000018: # the Museum. Many thanks to both. The images (with suitable reduction
015191,000019: # in storage size and consequent reduction in image quality as well) are
015192,000020: # available online at www.ibiblio.org/apollo. If for some reason you
015193,000021: # find that the images are illegible, contact me at info@sandroid.org
015194,000022: # about getting access to the (much) higher-quality images which Paul
015195,000023: # actually created.
015196,000024:
015197,000025: # Notations on the hardcopy document read, in part:
015198,000026:
015199,000027: # Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
015200,000028: # 16:27 JULY 14, 1969
015201,000029:
015202,000030: # Page 364
015203,000031: 15,2050 BANK 15
015204,000032:
015205,000033: 22,2000 SETLOC KALCMON1
015206,000034: 22,2000 BANK
015207,000035:
015208,000036: # DETECTING GIMBAL LOCK
015209,000037: 22,2744 22,2744 LOCSKIRT EQUALS NOGIMLOC
015210,000038:
015211,000039: 22,2744 77614 NOGIMLOC SET
015212,000040: 22,2745 01074 CALCMAN3
015213,000041: 22,2746 70740 WCALC LXC,1 DLOAD*
015214,000042: 22,2747 01325 RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
015215,000043: 22,2750 04772 ARATE,1 # FROM A LIST OF FOUR
015216,000044: 22,2751 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
015217,000045: 22,2752 44527 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
015218,000046: # ABOUT COF
015219,000047: 22,2753 74343 DLOAD* VXSC
015220,000048: 22,2754 04772 ARATE,1
015221,000049: 22,2755 03271 COF
015222,000050: 22,2756 17326 STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
015223,000051: 22,2757 03336 AM
015224,000052: 22,2760 55605 DMP DDV*
015225,000053: 22,2761 05002 ANGLTIME
015226,000054: 22,2762 04772 ARATE,1
015227,000055: 22,2763 77661 SR
015228,000056: 22,2764 20606 5
015229,000057: 22,2765 03334 STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
015230,000058: 22,2766 77614 SETGO
015231,000059: 22,2767 01035 CALCMAN2 # D(OFF) = CONTINUE MANEUVER
015232,000060: 22,2770 45010 NEWANGL +1 # 1(ON) = START MANEUVER
015233,000061:
015234,000062: # THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
015235,000063: # LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
015236,000064:
015237,000065: 22,2771 00221 24255 ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
015238,000066:
015239,000067: 22,2773 00554 02660 2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
015240,000068:
015241,000069: 22,2775 02660 13301 2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
015242,000070:
015243,000071: 22,2777 16161 30707 2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
015244,000072:
015245,000073: 22,3001 00003 04000 ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
015246,000074: # MANEUVER ANGLE TO MANEUVER TIME
015247,000075:
015248,000076:
End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc