Source Code
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These source-code files were obtained by digitally photographing
an Artemis 72 (Apollo 15-17 Command Module) program listing from a private
collection and then
modifying pre-existing Comanche 55 (Apollo 11) source files to
incorporate changes. Photography was by Ron Burkey, and transcription
was performed by a team of volunteers. Note that the page images
presented online are of reduced quality, and that additional images
may be available. Report any conversion errors or legibility
problems in page images to info@sandroid.org.
Notations on the program listing read, in part:GAP: ASSEMBLE REVISION 072 OF AGC PROGRAM ARTEMIS BY NASA 2021114-011 11:40 FEB. 26, 1971Note that the date is the date of the printout, not the date of the program revision. |
052893,000002: ## Copyright: Public domain.
052894,000003: ## Filename: LATITUDE_LONGITUDE_SUBROUTINES.agc
052895,000004: ## Purpose: Part of the source code for Artemis (i.e., Colossus 3),
052896,000005: ## build 072. This is for the Command Module's (CM)
052897,000006: ## Apollo Guidance Computer (AGC), for
052898,000007: ## Apollo 15-17.
052899,000008: ## Assembler: yaYUL
052900,000009: ## Contact: Sergio Navarro <sergionavarrog@gmail.com>
052901,000010: ## Website: www.ibiblio.org/apollo/index.html
052902,000011: ## Page Scans: www.ibiblio.org/apollo/ScansForConversion/Artemis072/
052903,000012: ## Mod history: 2009-09-03 SN Adapted from corresponding Comanche 055 file.
052904,000013: ## 2009-09-04 JL Fixed typos.
052905,000014: ## 2010-02-20 RSB Un-##'d this header.
052906,000015: ## 2010-04-13 JL Fixed a typo (' instead of #).
052907,000016: ## 2010-08-15 JL Fixed indentation.
052908,000017: ## 2017-02-05 RSB Proofed comment text by diff'ing vs Comanche 55
052909,000018: ## and corrected errors found.
052910,000019: ## 2017-03-15 RSB Comment-text fixes identified in 5-way
052911,000020: ## side-by-side diff of Luminary 69/99/116/131/210.
052912,000021:
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Page 1236 |
052914,000023: # SUBROUTINE TO CONVERT RAD VECTOR AT GIVEN TIME TO LAT,LONG AND ALT
052915,000024:
052916,000025: # CALLING SEQUENCE
052917,000026:
052918,000027: # L-1 CALL
052919,000028: # L LAT-LONG
052920,000029:
052921,000030: # SUBROUTINES USED
052922,000031:
052923,000032: # R-TO-RP, ARCTAN, SETGAMMA, SETRE
052924,000033:
052925,000034: # ERASABLE INIT. REQ.
052926,000035:
052927,000036: # AXO, -AYO, AZO, TEPHEM (SET AT LAUNCH TIME)
052928,000037: # ALPHAV = POSITION VECTOR METERS B-29
052929,000038: # MPAC -- TIME (CSECS B-28)
052930,000039: # ERADFLAG =1, TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
052931,000040: # LUNAFLAG=0 FOR EARTH, 1 FOR MOON
052932,000041:
052933,000042: # OUTPUT
052934,000043:
052935,000044: # LATITUDE IN LAT (REVS. B-0)
052936,000045: # LONGITUDE IN LONG (REVS. B-0)
052937,000046: # ALTITUDE IN ALT METERS B-29
052938,000047:
052939,000048: 13,2000 SETLOC LATLONG
052940,000049: 13,2000 BANK
052941,000050:
052942,000051: 13,2453 COUNT* $$/LT-LG
052943,000052: 13,2453 E4,1551 EBANK= ALPHAV
052944,000053: 13,2453 40220 LAT-LONG STQ SETPD
052945,000054: 13,2454 02241 INCORPEX
052946,000055: 13,2455 00001 0D
052947,000056: 13,2456 24007 STOVL 6D # SAVE TIME IN 6-7D FOR R-TO-RP
052948,000057: 13,2457 02152 ALPHAV
052949,000058: 13,2460 51406 PUSH ABVAL # 0-5D= R FOR R-TO-RP
052950,000059: 13,2461 16301 STODL ALPHAM # ABS. VALUE OF R FOR ALT FORMULA BELOW
052951,000060: 13,2462 11762 ZEROVEC # SET MPAC=0 FOR EARTH, NON-ZERO FOR MOON
052952,000061: 13,2463 71414 BOFF COS # USE COS(0) TO GET NON-ZERO IN MPAC
052953,000062: 13,2464 01743 LUNAFLAG # 0=EARTH,1=MOON
052954,000063: 13,2465 26466 CALLRTRP
052955,000064: 13,2466 77624 CALLRTRP CALL
052956,000065: 13,2467 55370 R-TO-RP # RP VECTOR CONVERTED FROM R B-29
052957,000066: 13,2470 77656 UNIT # UNIT RP B-1
052958,000067: 13,2471 36152 STCALL ALPHAV # U2= 1/2 SINL FOR SETRE SUBR BELOW
052959,000068: 13,2472 35766 SETGAMMA # SET GAMMA=B2/A2 FOR EARTH, =1 FOR MOON
052960,000069: 13,2473 77624 CALL # SCALED B-1
052961,000070: 13,2474 26654 SETRE # CALC RE METERS B-29
052962,000071: 13,2475 63545 DLOAD DSQ
052963,000072: 13,2476 02152 ALPHAV
052964,000073: 13,2477 63525 PDDL DSQ
052965,000074: 13,2500 02154 ALPHAV +2
052966,000075: 13,2501 75415 DAD SQRT
052967,000076: 13,2502 76405 DMP SL1R
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Page 1237 |
052969,000078: 13,2503 00011 GAMRP
052970,000079: 13,2504 14021 STODL COSTH # COS(LAT) B-1
052971,000080: 13,2505 02156 ALPHAV +4
052972,000081: 13,2506 34023 STCALL SINTH # SIN(LAT) B-1
052973,000082: 13,2507 26614 ARCTAN
052974,000083: 13,2510 14747 STODL LAT # LAT B0
052975,000084: 13,2511 02152 ALPHAV
052976,000085: 13,2512 14021 STODL COSTH # COS(LONG) B-1
052977,000086: 13,2513 02154 ALPHAV +2
052978,000087: 13,2514 34023 STCALL SINTH # SIN(LONG) B-1
052979,000088: 13,2515 26614 ARCTAN
052980,000089: 13,2516 14751 STODL LONG # LONG. REVS B-0 IN RANGE -1/2 TO 1/2
052981,000090: 13,2517 02301 ALPHAM
052982,000091: 13,2520 77625 DSU # ALT= R-RE METERS B-29
052983,000092: 13,2521 02240 ERADM
052984,000093: 13,2522 34753 STCALL ALT # EXIT WITH ALT METERS B-29
052985,000094: 13,2523 02241 INCORPEX
052986,000095:
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Page 1238 |
052988,000097: # SUBROUTINE TO CONVERT LAT,LONG,ALT AT GIVEN TIME TO RADIUS VECTOR
052989,000098:
052990,000099: # CALLING SEQUENCE
052991,000100:
052992,000101: # L-1 CALL
052993,000102: # L LALOTORV
052994,000103:
052995,000104: # SUBROUTINES USED
052996,000105:
052997,000106: # SETGAMMA, SETRE, RP-TO-R
052998,000107:
052999,000108: # ERASABLE INIT. REQ.
053000,000109:
053001,000110: # AXO, AYO, AZO, TEPHEM SET AT LAUNCH TIME
053002,000111: # LAT -- LATITUDE (REVS B0)
053003,000112: # LONG -- LONGITUDE (REVS B0)
053004,000113: # ALT -- ALTITUDE (METERS) B-29
053005,000114: # MPAC -- TIME (CSECS B-28)
053006,000115: # ERADFLAG =1 TO COMPUTE EARTH RADIUS, =0 FOR FIXED EARTH RADIUS
053007,000116: # LUNAFLAG=0 FOR EARTH, 1 FOR MOON
053008,000117:
053009,000118: # OUTPUT
053010,000119:
053011,000120: # R-VECTOR IN ALPHAV (METERS B-29)
053012,000121:
053013,000122: 13,2524 40220 LALOTORV STQ SETPD # LAT,LONG,ALT TO R VECTOR
053014,000123: 13,2525 02241 INCORPEX
053015,000124: 13,2526 00001 0D
053016,000125: 13,2527 34007 STCALL 6D # 6-7D = TIME FOR RP-TO-R
053017,000126: 13,2530 35766 SETGAMMA # GAMMA = B2/A2 FOR EARTH, 1 FOR MOON B-1
053018,000127: 13,2531 73545 DLOAD SIN # COS(LONG)COS(LAT) IN MPAC
053019,000128: 13,2532 00747 LAT # UNIT RP = SIN(LONG)COS(LAT) 2-3D
053020,000129: 13,2533 65275 DMPR PDDL # PD 2 GAMMA*SIN(LAT) 0-1D
053021,000130: 13,2534 00011 GAMRP
053022,000131: 13,2535 00747 LAT # 0-1D = GAMMA*SIN(LAT) B-2
053023,000132: 13,2536 65346 COS PDDL # PD4 2-3D = COS(LAT) B-1 TEMPORARILY
053024,000133: 13,2537 00751 LONG
053025,000134: 13,2540 57356 SIN DMPR # PD 2
053026,000135: 13,2541 71525 PDDL COS # PD 4 2-3D = SIN(LONG)COS(LAT) B-2
053027,000136: 13,2542 00747 LAT
053028,000137: 13,2543 71525 PDDL COS # PD 6 4-5D = COS(LAT) B-1 TEMPORARILY
053029,000138: 13,2544 00751 LONG
053030,000139: 13,2545 55475 DMPR VDEF # PD4 MPAC = COS(LONG)COS(LAT) B-2
053031,000140: 13,2546 41456 UNIT PUSH # 0-5D = UNIT RP FOR RP-TO-R SUBR.
053032,000141: 13,2547 36152 STCALL ALPHAV # ALPHAV +4= SINL FOR SETRE SUBR.
053033,000142: 13,2550 26654 SETRE # RE METERS B-29
053034,000143: 13,2551 43145 DLOAD BOFF # SET MPAC = 0 FOR EARTH, NON-ZERO FOR MOON
053035,000144: 13,2552 11762 ZEROVEC
053036,000145: 13,2553 01743 LUNAFLAG
053037,000146: 13,2554 26556 CALLRPRT
053038,000147: 13,2555 77746 COS # USE COS(0) TO GET NON-ZERO IN MPAC
053039,000148: 13,2556 77624 CALLRPRT CALL
053040,000149: 13,2557 55345 RP-TO-R # EXIT WITH UNIT R VECTOR IN MPAC
053041,000150: 13,2560 16152 STODL ALPHAV
053042,000151: 13,2561 02240 ERADM
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Page 1239 |
053044,000153: 13,2562 74215 DAD VXSC # (RE + ALT)(UNIT R) METERS B-30
053045,000154: 13,2563 00753 ALT
053046,000155: 13,2564 02152 ALPHAV
053047,000156: 13,2565 77772 VSL1 # R METERS B-29
053048,000157: 13,2566 36152 STCALL ALPHAV # EXIT WITH R IN METERS B-29
053049,000158: 13,2567 02241 INCORPEX
053050,000159:
053051,000160: # SUBROUTINE TO COMPUTE EARTH RADIUS
053052,000161:
053053,000162: # INPUT
053054,000163:
053055,000164: # 1/2 SIN LAT IN ALPHAV +4
053056,000165:
053057,000166: # OUTPUT
053058,000167:
053059,000168: # EARTH RADIUS IN ERADM AND MPAC (METERS B-29)
053060,000169:
053061,000170: 13,2570 63545 GETERAD DLOAD DSQ
053062,000171: 13,2571 02156 ALPHAV +4 # SIN**2(L)
053063,000172: 13,2572 44352 SL1 BDSU
053064,000173: 13,2573 11760 DP1/2 # COS**2(L)
053065,000174: 13,2574 44275 DMPR BDSU
053066,000175: 13,2575 26611 EE
053067,000176: 13,2576 11760 DP1/2
053068,000177: 13,2577 75465 BDDV SQRT
053069,000178: 13,2600 26605 B2XSC
053070,000179: 13,2601 77622 SR4R
053071,000180: 13,2602 02240 STORE ERADM
053072,000181: 13,2603 77616 RVQ
053073,000182:
053074,000183: # THE FOLLOWING CONSTANTS WERE COMPUTED WITH A=6378166, B=6356784 METERS
053075,000184: # B2XSC = B**2 SCALED B-51
053076,000185: # B2/A2 = B**2/A**2 SCALED B-1
053077,000186: # EE = (1-B**2/A**2) SCALED B-0
053078,000187:
053079,000188: 13,2604 00446 00305 B2XSC 2DEC .0179450689 # B**2 SCALED B-51
053080,000189: 13,2606 04,3757 DP1/2 = XUNIT
053081,000190: 13,2606 17711 05254 B2/A2 2DEC .9933064884 B-1 # GAMMA= B**2/A**2 B-1
053082,000191: 13,2610 00155 25250 EE 2DEC 6.6935116 E-3 # (1-B**2/A**2) B-0
053083,000192: 13,2612 00302 17755 ERAD 2DEC 6373338 B-29 # PAD RADIUS
053084,000193:
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Page 1240 |
053086,000195: # ARCTAN SUBROUTINE
053087,000196:
053088,000197: # CALLING SEQUENCE
053089,000198:
053090,000199: # SIN THETA IN SINTH B-1
053091,000200: # COS THETA IN COSTH B-1
053092,000201: # CALL ARCTAN
053093,000202:
053094,000203: # OUTPUT
053095,000204: # ARCTAN THETA IN MPAC AND THETA B-0 IN RANGE -1/2 TO +1/2
053096,000205:
053097,000206: 13,2614 77600 ARCTAN BOV
053098,000207: 13,2615 26616 CLROVFLW
053099,000208: 13,2616 63545 CLROVFLW DLOAD DSQ
053100,000209: 13,2617 00023 SINTH
053101,000210: 13,2620 63525 PDDL DSQ
053102,000211: 13,2621 00021 COSTH
053103,000212: 13,2622 77615 DAD
053104,000213: 13,2623 75454 BZE SQRT
053105,000214: 13,2624 26642 ARCTANXX # ATAN=0/0 SET THETA=0
053106,000215: 13,2625 40065 BDDV BOV
053107,000216: 13,2626 00023 SINTH
053108,000217: 13,2627 26647 ATAN=90
053109,000218: 13,2630 67542 SR1 ASIN
053110,000219: 13,2631 00025 STORE THETA
053111,000220: 13,2632 50125 PDDL BMN
053112,000221: 13,2633 00021 COSTH
053113,000222: 13,2634 26636 NEGCOS
053114,000223: 13,2635 43545 DLOAD RVQ
053115,000224: 13,2636 57545 NEGCOS DLOAD DCOMP
053116,000225: 13,2637 43244 BPL DAD
053117,000226: 13,2640 26644 NEGOUT
053118,000227: 13,2641 11760 DP1/2
053119,000228: 13,2642 00025 ARCTANXX STORE THETA
053120,000229: 13,2643 77616 RVQ
053121,000230:
053122,000231: 13,2644 52025 NEGOUT DSU GOTO
053123,000232: 13,2645 11760 DP1/2
053124,000233: 13,2646 26642 ARCTANXX
053125,000234: 13,2647 75345 ATAN=90 DLOAD SIGN
053126,000235: 13,2650 33412 LODP1/4
053127,000236: 13,2651 00023 SINTH
053128,000237: 13,2652 00025 STORE THETA
053129,000238: 13,2653 77616 RVQ
053130,000239:
053131,000240: 13,2654 04,3761 2DZERO = DPZERO
053132,000241:
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Page 1241 |
053134,000243: # ..... SETGAMMA SUBROUTINE .....
053135,000244: # SUBROUTINE TO SET GAMMA FOR THE LAT-LONG AND LALOTORV SUBROUTINES
053136,000245:
053137,000246: # GAMMA = B**2/A**2 FOR EARTH (B-1)
053138,000247: # GAMMA = 1 FOR MOON (B-1)
053139,000248:
053140,000249: # CALLING SEQUENCE
053141,000250: # L CALL
053142,000251: # L+1 SETGAMMA
053143,000252:
053144,000253: # INPUT
053145,000254: # LUNAFLAG=0 FOR EARTH, =1 FOR MOON
053146,000255:
053147,000256: # OUTPUT
053148,000257: # GAMMA IN GAMRP (B-1)
053149,000258:
053150,000259: 16,2000 SETLOC LATLONG1
053151,000260: 16,2000 BANK
053152,000261: 16,3766 COUNT* $$/LT-LG
053153,000262:
053154,000263: 16,3766 43145 SETGAMMA DLOAD BOFF # BRANCH FOR EARTH
053155,000264: 16,3767 26607 B2/A2 # EARTH GAMMA
053156,000265: 16,3770 01743 LUNAFLAG
053157,000266: 16,3771 35774 SETGMEX
053158,000267: 16,3772 77735 SLOAD
053159,000268: 16,3773 11760 1B1 # MOON GAMMA
053160,000269: 16,3774 00011 SETGMEX STORE GAMRP
053161,000270: 16,3775 77616 RVQ
053162,000271: 16,3776 GAMRP = 8D
053163,000272: 13,2000 SETLOC LATLONG
053164,000273: 13,2000 BANK
053165,000274:
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Page 1242 |
053167,000276: # ..... SETRE SUBROUTINE .....
053168,000277: # SUBROUTINE TO SET RE (EARTH OR MOON RADIUS)
053169,000278:
053170,000279: # RE = RM FOR MOON
053171,000280: # RE = RREF FOR FIXED EARTH RADIUS OR COMPUTED RF FOR FISCHER ELLIPSOID
053172,000281:
053173,000282: # CALLING SEQUENCE
053174,000283: # L CALL
053175,000284: # L+1 SETRE
053176,000285:
053177,000286: # SUBROUTINES USED
053178,000287: # GETERAD
053179,000288:
053180,000289: # INPUT
053181,000290: # ERADFLAG = 0 FOR FIXED RE, 1 FOR COMPUTED RE
053182,000291: # ALPHAV +4 = 1/2 SINL IF GETERAD IS CALLED
053183,000292: # LUNAFLAG = 0 FOR EARTH, =1 FOR MOON
053184,000293:
053185,000294: # OUTPUT
053186,000295: # ERADM = 504RM FOR MOON (METERS B-29)
053187,000296: # ERADM = ERAD OR COMPUTED RF FOR EARTH (METERS B-29)
053188,000297:
053189,000298: 13,2654 71220 SETRE STQ DLOAD
053190,000299: 13,2655 00051 SETREX
053191,000300: 13,2656 26701 504RM
053192,000301: 13,2657 71214 BON DLOAD # BRANCH FOR MOON
053193,000302: 13,2660 01703 LUNAFLAG
053194,000303: 13,2661 26671 TSTRLSRM
053195,000304: 13,2662 26613 ERAD
053196,000305: 13,2663 45014 BOFF CALL # ERADFLAG=0 FOR FIXED RE, 1 FOR COMPUTED
053197,000306: 13,2664 00742 ERADFLAG
053198,000307: 13,2665 26667 SETRXX
053199,000308: 13,2666 26570 GETERAD
053200,000309: 13,2667 36240 SETRXX STCALL ERADM # EXIT WITH RE OR RM METERS B-29
053201,000310: 13,2670 00051 SETREX
053202,000311: 13,2671 77214 TSTRLSRM BON VLOAD # ERADFLAG=0, SET R0=RLS
053203,000312: 13,2672 00702 ERADFLAG # =1 R0=RM
053204,000313: 13,2673 26667 SETRXX
053205,000314: 13,2674 02026 RLS
053206,000315: 13,2675 64446 ABVAL SR2R # SCALE FROM B-27 TO B-29
053207,000316: 13,2676 77650 GOTO
053208,000317: 13,2677 26667 SETRXX
053209,000318: 13,2700 0000051 SETREX = S2
053210,000319: 13,2700 00065 01265 504RM 2DEC 1738090 B-29 # METERS B-29 (MOON RADIUS)
End of include-file LATITUDE_LONGITUDE_SUBROUTINES.agc. Parent file is MAIN.agc