Source Code
015158,000001: # Copyright: Public domain.
015159,000002: # Filename: GIMBAL_LOCK_AVOIDANCE.agc
015160,000003: # Purpose: Part of the source code for Luminary 1A build 099.
015161,000004: # It is part of the source code for the Lunar Module's (LM)
015162,000005: # Apollo Guidance Computer (AGC), for Apollo 11.
015163,000006: # Assembler: yaYUL
015164,000007: # Contact: Ron Burkey <info@sandroid.org>.
015165,000008: # Website: www.ibiblio.org/apollo.
015166,000009: # Page: 364
015167,000010: # Mod history: 2009-05-17 RSB Adapted from the corresponding
015168,000011: # Luminary131 file, using page
015169,000012: # images from Luminary 1A.
015170,000013:
015171,000014: # This source code has been transcribed or otherwise adapted from
015172,000015: # digitized images of a hardcopy from the MIT Museum. The digitization
015173,000016: # was performed by Paul Fjeld, and arranged for by Deborah Douglas of
015174,000017: # the Museum. Many thanks to both. The images (with suitable reduction
015175,000018: # in storage size and consequent reduction in image quality as well) are
015176,000019: # available online at www.ibiblio.org/apollo. If for some reason you
015177,000020: # find that the images are illegible, contact me at info@sandroid.org
015178,000021: # about getting access to the (much) higher-quality images which Paul
015179,000022: # actually created.
015180,000023:
015181,000024: # Notations on the hardcopy document read, in part:
015182,000025:
015183,000026: # Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
015184,000027: # 16:27 JULY 14, 1969
015185,000028:
015186,000029: # Page 364
015187,000030: 15,2050 BANK 15
015188,000031:
015189,000032: 22,2000 SETLOC KALCMON1
015190,000033: 22,2000 BANK
015191,000034:
015192,000035: # DETECTING GIMBAL LOCK
015193,000036: 22,2744 22,2744 LOCSKIRT EQUALS NOGIMLOC
015194,000037:
015195,000038: 22,2744 77614 NOGIMLOC SET
015196,000039: 22,2745 01074 CALCMAN3
015197,000040: 22,2746 70740 WCALC LXC,1 DLOAD*
015198,000041: 22,2747 01325 RATEINDX # CHOOSE THE DESIRED MANEUVER RATE
015199,000042: 22,2750 04772 ARATE,1 # FROM A LIST OF FOUR
015200,000043: 22,2751 45002 SR4 CALL # COMPUTE THE INCREMENTAL ROTATION MATRIX
015201,000044: 22,2752 44527 DELCOMP # DEL CORRESPONDING TO A 1 SEC ROTATION
015202,000045: # ABOUT COF
015203,000046: 22,2753 74343 DLOAD* VXSC
015204,000047: 22,2754 04772 ARATE,1
015205,000048: 22,2755 03271 COF
015206,000049: 22,2756 17326 STODL BRATE # COMPONENT MANEUVER RATES 45 DEG/SEC
015207,000050: 22,2757 03336 AM
015208,000051: 22,2760 55605 DMP DDV*
015209,000052: 22,2761 05002 ANGLTIME
015210,000053: 22,2762 04772 ARATE,1
015211,000054: 22,2763 77661 SR
015212,000055: 22,2764 20606 5
015213,000056: 22,2765 03334 STORE TM # MANEUVER EXECUTION TIME SCALED AS T2
015214,000057: 22,2766 77614 SETGO
015215,000058: 22,2767 01035 CALCMAN2 # D(OFF) = CONTINUE MANEUVER
015216,000059: 22,2770 45010 NEWANGL +1 # 1(ON) = START MANEUVER
015217,000060:
015218,000061: # THE FOUR SELECTABLE FREE FALL MANEUVER RATES SELECTED BY
015219,000062: # LOADING RATEINDX WITH 0, 2, 4, 6, RESPECTIVELY
015220,000063:
015221,000064: 22,2771 00221 24255 ARATE 2DEC .0088888888 # = 0.2 DEG/SEC $ 22.5 DEG/SEC
015222,000065:
015223,000066: 22,2773 00554 02660 2DEC .0222222222 # = 0.5 DEG/SEC $ 22.5 DEG/SEC
015224,000067:
015225,000068: 22,2775 02660 13301 2DEC .0888888888 # = 2.0 DEG/SEC $ 22.5 DEG/SEC
015226,000069:
015227,000070: 22,2777 16161 30707 2DEC .4444444444 # = 10.0 DEG/SEC $ 22.5 DEG/SEC
015228,000071:
015229,000072: 22,3001 00003 04000 ANGLTIME 2DEC .0001907349 # = 100B-19 FUDGE FACTOR TO CONVERT
015230,000073: # MANEUVER ANGLE TO MANEUVER TIME
015231,000074:
015232,000075:
End of include-file GIMBAL_LOCK_AVOIDANCE.agc. Parent file is MAIN.agc