https://github.com/virtualagc/virtualagc
Tip revision: a8d66c8ae3c4d967053e2bfb4298e90182cbeff2 authored by Ron Burkey on 06 March 2024, 12:40:55 UTC
Minor tweaks associated with supporting Skylark 48.
Minor tweaks associated with supporting Skylark 48.
Tip revision: a8d66c8
LAMBERT_AIMPOINT_GUIDANCE.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: LAMBERT_AIMPOINT_GUIDANCE.agc
## Purpose: A section of Luminary revision 97.
## It is part of the reconstructed source code for the
## second release of the flight software for the Lunar
## Module's (LM) Apollo Guidance Computer (AGC) for Apollo 11.
## It was created to fix two incorrect ephemeris constants in
## Luminary 96, as described by anomaly report LNY-59.
## The code has been recreated from a copy of Luminary 99
## revision 001, using asterisks indicating changed lines in
## the listing and Luminary Memos #83 and #85, which list
## changes between Luminary 97 and 98, and 98 and 99. The
## code has been adapted such that the resulting bugger words
## exactly match those specified for Luminary 97 in NASA drawing
## 2021152D, which gives relatively high confidence that the
## reconstruction is correct.
## Reference: pp. 651-653
## Assembler: yaYUL
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 2019-07-28 MAS Created from Luminary 99.
## Page 651
# GENERAL LAMBERT AIMPOINT GUIDANCE **
# WRITTEN BY RAMA M AIYAWAR
# PROGRAM P-31 DESCRIPTION **
#
# 1. TO ACCEPT TARGETING PARAMETERS OBTAINED FROM A SOURCE EXTERNAL
# TO THE LEM AND COMPUTE THERE FROM THE REQUIRED-VELOCITY AND
# OTHER INITIAL CONDITIONS REQUIRED BY LM FOR DESIRED MANEUVER.
# THE TARGETING PARAMETERS ARE TIG (TIME OF IGNITION), TARGET
# VECTOR (RTARG), AND THE TIME FROM TIG UNTIL THE TARGET IS
# REACHED (DELLT4), DESIRED TIME OF FLIGHT FROM RINIT TO RTARG..
# ASSUMPTIONS **
#
# 1. THE TARGET PARAMETERS MAY HAVE BEEN LOADED PRIOR TO THE
# EXECUTION OF THIS PROGRAM.
# 2. THIS PROGRAM IS APPLICABLE IN EITHER EARTH OR LUNAR ORBIT.
# 3. THIS PROGRAM IS DESIGNED FOR ONE-MAN OPERATION, AND SHOULD
# BE SELECTED BY THE ASTRONAUT BY DSKY ENTRY V37 E31.
# SUBROUTINES USED **
#
# MANUPARM, TTG/N35, R02BOTH, MIDGIM, DISPMGA, FLAGDOWN, BANKCALL,
# GOTOPOOH, ENDOFJOB, PHASCHNG, GOFLASHR, GOFLASH.
#
# MANUPARM CALCULATES APOGEE, PERIGEE ALTITUDES AND DELTAV DESIRED
# FOR THE MANEUVER.
#
# TTG/N35 CLOCKTASK - UPDATES CLOCK.
#
# MIDGIM CALCULATES MIDDLE GIMBAL ANGLE FOR DISPLAY.
#
# R02BOTH IMU - STATUS CHECK ROUTINE.
# DISPLAYS USED IN P-31LM **
#
# V06N33 DISPLAY SOTRED TIG (IN HRS. MINS. SECS)
# V06N42 DISPLAY APOGEE, PERIGEE, DELTAV.
# V16N35 DISPLAY TIME FROM TIG.
# V06N45 TIME FROM IGNITION AND MIDDLE GIMBAL ANGLE.
# ERASABLE INITIALIZATION REQUIRED **
#
# TIG TIME OF IGNITION DP (B+28) CS.
#
# DELLT4 DESIRED TIME OF FLIGHT DP (B+28) CS
# FROM RINIT TO RTARG.
#
# RTARG RADIUS VECTOR OF TARGET POSITION VECTOR
# RADIUS VECTOR SCALED TO (B+29)METERS IF EARTH ORBIT
## Page 652
# RADIUS VECTOR SCALED TO (B+27)METERS IF MOON ORBIT
# OUTPUT **
#
# HAPO APOGEE ALTITUDE
# HPER PERIGEE ALTITUDE
# VGDISP MAG. OF DELTAV FOR DISPLAY, SCALING B+7 M/CS EARTH
# MAG. OF DELTAV FOR DISPLAY, SCALING B+5 M/CS MOON
# MIDGIM MIDDLE GIMBAL ANGLE
# XDELVFLG RESETS XDELVFLG FOR LAMBERT VG COMPUTATIONS
# ALARMS OR ABORTS NONE **
# RESTARTS ARE VIA GROUP 4 **
SETLOC GLM
BANK
EBANK= SUBEXIT
COUNT* $$/P31
P31 TC P20FLGON
CAF V06N33 # TIG
TC VNPOOH
TC INTPRET
CLEAR DLOAD
UPDATFLG
TIG
STCALL TDEC1 # INTEGRATE STATE VECTORS TO TIG
LEMPREC
VLOAD SETPD
RATT
0D
STORE RTIG
STOVL RINIT
VATT
STORE VTIG
STODL VINIT
P30ZERO
PUSH PDDL # E4 AND NUMIT = 0
DELLT4
DAD SXA,1
TIG
RTX1
STORE TPASS4
SXA,2 CALL
RTX2
INITVEL
VLOAD PUSH
## Page 653
DELVEET3
STORE DELVSIN
ABVAL CLEAR
XDELVFLG
STCALL VGDISP
GET.LVC
VLOAD PDVL
RTIG
VIPRIME
CALL
PERIAPO1
CALL
SHIFTR1
CALL # LIMIT DISPLAY TO 9999.9 N. MI.
MAXCHK
STODL HPER
4D
CALL
SHIFTR1
CALL # LIMIT DISPLAY TO 9999.9 N. MI.
MAXCHK
STORE HAPO
EXIT
CAF V06N81 # DELVLVC
TC VNPOOH
CAF V06N42 # HAPO, HPER, VGDISP
TC VNPOOH
TC INTPRET
REVN1645 SET CALL # TRKMKCNT, TTOGO, +MGA
FINALFLG
VN1645
GOTO
REVN1645