INFLIGHT_ALIGNMENT_ROUTINES.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: INFLIGHT_ALIGNMENT_ROUTINES.agc
## Purpose: The main source file for Luminary revision 069.
## It is part of the source code for the original release
## of the flight software for the Lunar Module's (LM) Apollo
## Guidance Computer (AGC) for Apollo 10. The actual flown
## version was Luminary 69 revision 2, which included a
## newer lunar gravity model and only affected module 2.
## This file is intended to be a faithful transcription, except
## that the code format has been changed to conform to the
## requirements of the yaYUL assembler rather than the
## original YUL assembler.
## Reference: pp. 1244-1253
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2016-12-13 MAS Created from Luminary 99.
## 2016-12-18 MAS Updated from comment-proofed Luminary 99 version.
## 2017-01-16 RRB Updated for Luminary 69.
## 2017-01-21 HG Add missing interpretive operation BONCLR
## 2017-01-28 RSB Proofed comment text using octopus/prooferComments
## but no errors found.
## 2017-03-17 RSB Comment-text fixes identified in diff'ing
## Luminary 99 vs Comanche 55.
## Page 1244
BANK 22
SETLOC INFLIGHT
BANK
EBANK= XSM
# CALCGTA COMPUTES THE GYRO TORQUE ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
#
# THE INPUT IS THE DESIRED STABLE MEMBER COORDINATES REFERRED TO PRESENT STABLE MEMBER COORDINATES. THE THREE
# HALF-UNIT VECTORS ARE STORED AT XDC, YDC, AND ZDC.
#
# THE OUTPUTS ARE THE THREE GYRO TORQUING ANGLES TO BE APPLIED TO THE Y, Z, AND X GYROS AND ARE STORED DP AT IGC,
# MGC, AND OGC RESPECTIVELY.
COUNT* $$/INFLT
CALCGTA ITA DLOAD # PUSHDOWN 00-03,16D-27D,34D-37D
S2 # XDC = (XD1 XD2 XD3)
XDC # YDC = (YD1 YD2 YD3)
PDDL PDDL # ZDC = (ZD1 ZD2 ZD3)
HI6ZEROS
XDC +4
DCOMP VDEF
UNIT
STODL ZPRIME # ZP = UNIT(-XD3 0 XD1) = (ZP1 ZP2 ZP3)
ZPRIME
SR1
STODL SINTH # SIN(IGC) = ZP1
ZPRIME +4
SR1
STCALL COSTH # COS(IGC) = ZP3
ARCTRIG
STODL IGC # Y GYRO TORQUING ANGLE FRACTION OF REV.
XDC +2
SR1
STODL SINTH # SIN(MGC) = XD2
ZPRIME
DMP PDDL
XDC +4 # PD00 = (ZP1)(XD3)
ZPRIME +4
DMP DSU
XDC # MPAC = (ZP3)(XD1)
STADR
STCALL COSTH # COS(MGC) = MPAC - PD00
ARCTRIG
## Page 1245
STOVL MGC # Z GYRO TORQUING ANGLE FRACTION OF REV.
ZPRIME
DOT
ZDC
STOVL COSTH # COS(OGC) = ZP . ZDC
ZPRIME
DOT
YDC
STCALL SINTH # SIN(OGC) = ZP . YDC
ARCTRIG
STCALL OGC # X GYRO TORQUING ANGLE FRACTION OF REV.
S2
## Page 1246
# ARCTRIG COMPUTES AN ANGLE GIVEN THE SINE AND COSINE OF THIS ANGLE.
#
# THE INPUTS ARE SIN/4 AND COS/4 STORED DP AT SINTH AND COSTH.
#
# THE OUTPUT IS THE CALCULATED ANGLE BETWEEN +.5 AND -.5 REVOLUTIONS AND STORED AT THETA. THE OUTPUT IS ALSO
# AVAILABLE AT MPAC.
ARCTRIG DLOAD ABS # PUSHDOWN 16D-21D
SINTH
DSU BMN
QTSN45 # ABS(SIN/4) - SIN(45)/4
TRIG1 # IF (-45,45) OR (135,-135)
DLOAD SL1 # (45,135) OR (-135,-45)
COSTH
ACOS SIGN
SINTH
STORE THETA # X = ARCCOS(COS) WITH SIGN(SIN)
RVQ
TRIG1 DLOAD SL1 # (-45,45) OR (135,-135)
SINTH
ASIN
STODL THETA # X = ARCSIN(SIN) WITH SIGN(SIN)
COSTH
BMN
TRIG2 # IF (135,-135)
DLOAD RVQ
THETA # X = ARCSIN(SIN) (-45,45)
TRIG2 DLOAD SIGN # (135,-135)
HIDPHALF
SINTH
DSU
THETA
STORE THETA # X = .5 WITH SIGN(SIN) - ARCSIN(SIN)
RVQ # (+) - (+) OR (-) - (-)
## Page 1247
# SMNB, NBSM, AND AXISROT, WHICH USED TO APPEAR HERE, HAVE BEEN
# COMBINED IN A ROUTINE CALLED AX*SR*T, WHICH APPEARS AMONG THE POWERED
# FLIGHT SUBROUTINES.
## Page 1248
# CALCGA COMPUTES THE CDU DRIVING ANGLES REQUIRED TO BRING THE STABLE MEMBER INTO THE DESIRED ORIENTATION.
#
# THE INPUTS ARE 1) THE NAVIGATION BASE COORDINATES REFERRED TO ANY COORDINATE SYSTEM. THE THREE HALF-UNIT
# VECTORS ARE STORED AT XNB, YNB, AND ZNB. 2) THE DESIRED STABLE MEMBER COORDINATES REFERRED TO THE SAME
# COORDINATE SYSTEM ARE STORED AT XSM, YSM, AND ZSM.
#
# THE OUTPUTS ARE THE THREE CDU DRIVING ANGLES AND ARE STORED SP AT THETAD, THETAD +1, AND THETAD +2.
CALCGA SETPD # PUSHDOWN 00-05, 16D-21D, 34D-37D
0
VLOAD VXV
XNB # XNB = OGA (OUTER GIMBAL AXIS)
YSM # YSM = IGA (INNER GIMBAL AXIS)
UNIT PUSH # PD0 = UNIT(OGA X IGA) = MGA
DOT ITA
ZNB
S2
STOVL COSTH # COS(OG) = MGA . ZNB
0
DOT
YNB
STCALL SINTH # SIN(OG) = MGA . YNB
ARCTRIG
STOVL OGC
0
VXV DOT # PROVISION FOR MG ANGLE OF 90 DEGREES
XNB
YSM
SL1
STOVL COSTH # COS(MG) = IGA . (MGA X OGA)
YSM
DOT
XNB
STCALL SINTH # SIN(MG) = IGA . OGA
ARCTRIG
STORE MGC
ABS DSU
.166...
BPL
GIMLOCK1 # IF ANGLE GREATER THAN 60 DEGREES
CALCGA1 VLOAD DOT
ZSM
0
STOVL COSTH # COS(IG) = ZSM . MGA
XSM
## Page 1249
DOT STADR
STCALL SINTH # SIN(IG) = XSM . MGA
ARCTRIG
STOVL IGC
OGC
RTB BONCLR
V1STO2S
CPHIFLAG
S2
STCALL THETAD
S2
GIMLOCK1 EXIT
TC ALARM
OCT 00401
TC UPFLAG # GIMBAL LOCK HAS OCCURED
ADRES GLOKFAIL
TC INTPRET
GOTO
CALCGA1
## Page 1250
# AXISGEN COMPUTES THE COORDINATES OF ONE COORDINATE SYSTEM REFERRED TO ANOTHER COORDINATE SYSTEM.
#
# THE INPUTS ARE 1) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM A STORED AT STARAD. 2) THE STAR2 VECTOR
# REFERRED TO COORDINATE SYSTEM A STORED AT STARAD +6. 3) THE STAR1 VECTOR REFERRED TO COORDINATE SYSTEM B STORED
# AT LOCATION 6 OF THE VAC AREA. 4) THE STAR2 VECTOR REFERRED TO COORDINATE SYSTEM B STORED AT LOCATION 12D OF
# THE VAC AREA.
#
# THE OUTPUT DEFINES COORDINATE SYSTEM A REFERRED TO COORDINATE SYSTEM B. THE THREE HALF-UNIT VECTORS ARE STORED
# AT LOCATIONS XDC, XDC +6, XDC +12D, AND STARAD, STARAD +6, STARAD +12D.
AXISGEN AXT,1 SSP # PUSHDOWN 00-30D,34D-37D
STARAD +6
S1
STARAD -6
SETPD
0
AXISGEN1 VLOAD* VXV* # 06D UA = S1
STARAD +12D,1 # STARAD +00D UB = S1
STARAD +18D,1
UNIT # 12D VA = UNIT(S1 X S2)
STORE STARAD +18D,1 # STARAD +06D VB = UNIT(S1 X S2)
VLOAD*
STARAD +12D,1
VXV* VSL1
STARAD +18D,1 # 18D WA = UA X VA
STORE STARAD +24D,1 # STARAD +12D WB = UB X VB
TIX,1
AXISGEN1
AXC,1 SXA,1
6
30D
AXT,1 SSP
18D
S1
6
AXT,2 SSP
6
S2
2
AXISGEN2 XCHX,1 VLOAD*
30D # X1=-6 X2=+6 X1=-6 X2=+4 X1=-6 X2=+2
0,1
## Page 1251
VXSC* PDVL* # J=(UA)(UB1) J=(UA)(UB2) J=(UA)(UB3)
STARAD +6,2
6,1
VXSC*
STARAD +12D,2
STOVL* 24D # K=(VA)(VB1) J=(VA)(VB2) J=(VA)(VB3)
12D,1
VXSC* VAD
STARAD +18D,2 # L=(WA)(WB1) J=(WA)(WB2) J=(WA)(WB3)
VAD VSL1
24D
XCHX,1 UNIT
30D
STORE XDC +18D,1 # XDC = L+J+K YDC = L+J+K ZDC = L+J+K
TIX,1
AXISGEN3
AXISGEN3 TIX,2
AXISGEN2
VLOAD
XDC
STOVL STARAD
YDC
STOVL STARAD +6
ZDC
STORE STARAD +12D
RVQ
## Page 1252
QTSN45 2DEC .1768
.166... 2DEC .1666666667
## Page 1253
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