### FILE="Main.annotation"

## Copyright: Public domain.

## Filename: IMU_CALIBRATION_AND_ALIGNMENT.agc

## Purpose: Part of the source code for Colossus, build 249.

## It is part of the source code for the Command Module's (CM)

## Apollo Guidance Computer (AGC), for Apollo 9.

## Assembler: yaYUL

## Reference: pp. 416-448.

## Contact: Ron Burkey <info@sandroid.org>.

## Website: www.ibiblio.org/apollo.

## Mod history: 08/11/04 RSB Began transcribing.

## 2010-10-24 JL Indentation fixes.

## 2011-05-07 JL Flag SBANK= workarounds for future removal.

## 2017-01-06 RSB Page numbers now agree with those on the

## original harcopy, as opposed to the PDF page

## numbers in 1701.pdf.

## 2017-01-14 RSB Cross-diff'd comment text (not whitespace)

## vs the already-proofed corresponding Colossus

## 237 and Comanche 55 source-code files

## and corrected errors found.

## 2017-06-17 MAS Globally removed all SBANK= workarounds.

## 2021-05-30 ABS Single instance of $$/P03 -> $$/PO3 to match scans.

##

## The contents of the "Colossus249" files, in general, are transcribed

## from a scanned copy of the program listing. Notations on this

## document read, in part:

##

## Assemble revision 249 of AGC program Colossus by NASA

## 2021111-041. October 28, 1968.

##

## This AGC program shall also be referred to as

## Colossus 1A

##

## Prepared by

## Massachusetts Institute of Technology

## 75 Cambridge Parkway

## Cambridge, Massachusetts

## under NASA contract NAS 9-4065.

##

## Refer directly to the online document mentioned above for further information.

## Please report any errors (relative to the scanned pages) to info@sandroid.org.

##

## In some cases, where the source code for Luminary 131 overlaps that of

## Colossus 249, this code is instead copied from the corresponding Luminary 131

## source file, and then is proofed to incorporate any changes.

## Page 416

# NAME - IMU PERFORMANCE TESTS 2

#

# DATE - MARCH 20, 1967

#

# BY - SYSTEM TEST GROUP 864-6900 EXT. 1274

#

# MODNO.- ZERO

#

# FUNCTIONAL DESCRIPTION

#

# POSITIONING ROUTINES FOR THE IMU PERFORMANCE TESTS AS WELL AS SOME OF

# THE TESTS THEMSELVES. FOR A DESCRIPTION OF THESE SUBROUTINES AND THE

# OPERATING PROCEDURES (TYPICALLY) SEE STG MEMO 685. THEORETICAL REF. E-1973

BANK 33

SETLOC IMUCAL

BANK

EBANK= POSITON

IMUTEST CA ZERO

TS DRIFTT

TS GEOCOMP1

CAF TESTTIME

TS LENGTHOT

TC COAALIGN # TAKE CARE OF DRIFT FLAG

CAF 1SECX

TS 1SECXT1

CA OC14400

TS 1/PIPADT

GUESS TC INTPRET # CALCULATE -COS LATITUDE AND SIN LATITUDE

CALL

LATAZCHK

COS DCOMP

SL1

STODL WANGI

LATITUDE

SIN SL1

STORE WANGO

EXIT

GEOIMUTT TC BANKCALL # GYROCOMPASS COMES IN HERE

CADR IMUZERO

TC IMUSTLLG

IMUBACK CA ZERO

TS NDXCTR

TS TORQNDX

TS TORQNDX +1

NBPOSPL CA DEC17

TS ZERONDX1

CA XNBADR

## Page 417

TC ZEROING

CA HALF

TS XNB

TC INTPRET

DLOAD SIN

AZIMUTH

STORE YNB +2

STODL ZNB +4

AZIMUTH

COS

STORE YNB +4

DCOMP

STORE ZNB +2

EXIT

TC CHECKMM

MM 03 # SEE IF IN OPTICAL VERIFICATION

TCF +2 # NO

TCF SETNBPOS +1 # YES

TC INTPRET

CALL

CALCGA

EXIT

TC BANKCALL

CADR IMUCOARS

CAF BIT14 # IF BIT14 SET, GIMBAL LOCK

MASK FLAGWRD3

EXTEND

BZF +2

INCR NDXCTR # +1 IF IN GIMBAL LOCK, OTHERWISE 0

TC DOWNFLAG # RESET GIMBAL LOCK FLAG

ADRES GLOKFAIL # BIT 14 FLAG 3

TC IMUSTLLG

CCS NDXCTR # IF ONE GO AND DO A PIPA TEST ONLY

TC PIPACHK # ALIGN AND MEASURE VERTICAL PIPA RATE

TC BANKCALL

CADR IMUFINE

TC IMUSTLLG

EXTEND

DCA PERFDLAY

TC LONGCALL

EBANK= POSITON

2CADR GOESTIMS

CA ESTICADR

TC JOBSLEEP

GOESTIMS CA ESTICADR

TC JOBWAKE

TC TASKOVER

ESTICADR CADR ESTIMS

## Page 418

TORQUE CA ZERO

TS DSPTEM2

CA DRIFTI

TS DSPTEM2 +1

INDEX POSITON

TS SOUTHDR -1

TC SHOW

PIPACHK INDEX NDXCTR # PIPA TEST

TC +1

TC EARTHR*

CA DEC57

TS LENGTHOT

CA ONE

TS RESULTCT

CA ZERO

INDEX PIPINDEX

TS PIPAX

TS DATAPL

TS DATAPL +4

TC CHECKG # PIP PULSE CATCHING ROUTINE

INHINT

CAF TWO

TC TWIDDLE

EBANK= XSM

ADRES PIPATASK

TC ENDOFJOB

PIPATASK EXTEND

DIM LENGTHOT

CA LENGTHOT

EXTEND

BZMF STARTPIP

CAF BIT10

TC TWIDDLE

EBANK= XSM

ADRES PIPATASK

STARTPIP CAF PRIO20

TC FINDVAC

EBANK= XSM

2CADR PIPJOBB

TC TASKOVER

PIPJOBB INDEX NDXCTR

TC +1

TC EARTHR*

CA LENGTHOT

EXTEND

BZMF +2

TC ENDOFJOB

CA FIVE

## Page 419

TS RESULTCT

TC CHECKG

EXTEND

DCS DATAPL

DAS DATAPL +4

TC INTPRET

DLOAD DSU

DATAPL +6

DATAPL +2

BPL CALL

AINGOTN

OVERFFIX

AINGOTN PDDL DDV

DATAPL +4

SL4 DMPR

DEC585 # DEC585 HAS BEEN REDEFINED FOR LEM

RTB

SGNAGREE

STORE DSPTEM2

EXIT

CCS NDXCTR

TC COAALIGN # TAKE PLATFORM OUT OF GIMBAL LOCK

TC SHOW

VERTDRFT CA 3990DEC # ABOUT 1 HOUR VERTICAL DRIFT TEST

TS LENGTHOT

INDEX POSITON

CS SOUTHDR -2

TS DRIFTT

CA XSM +4 # 0 IF POSN 4

EXTEND

BZF PON2

PON4 CS BIT5 # OFFSET PLATFORM

ADS ERCOMP1 +2

CA BIT5

ADS ERCOMP1

TCF PONG

PON2 CS BIT5

ADS ERCOMP1 +2

CA BIT5

ADS ERCOMP1 +4

PONG TC EARTHR*

CA ZERO # ALLOW ONLY SOUTH GYRO EARTH RATE COMPENS

TS ERVECTOR

TS ERVECTOR +1

GUESS1 CAF POSMAX

TS TORQNDX

TS TORQNDX +1

CA CDUX

TS LOSVEC

## Page 420

TC ESTIMS

VALMIS CA DRIFTO

TS DSPTEM2 +1

CA ZERO

TS DSPTEM2

TC SHOW

ENDTEST1 TC DOWNFLAG # IMU NOT IN USE

ADRES IMUSE # BIT 8 FLAG 0

CS ZERO

TC NEWMODEX +3

TC BANKCALL

CADR MKRELEAS

TC ENDEXT

## Page 421

OVERFFIX DAD DAD

DPPOSMAX

ONEDPP

RVQ

COAALIGN EXTEND # COARSE ALIGN SUBROUTINE

QXCH QPLACE

CA ZERO

TS THETAD

TS THETAD +1

TS THETAD +2

TC BANKCALL

CADR IMUCOARS

TC BANKCALL

CADR IMUSTALL

TC SOMERR2

TC QPLACE

IMUSTLLG EXTEND

QXCH QPLACE

TC COAALIGN +10

CHECKG EXTEND # PIP PULSE CATCHING ROUTINE

QXCH QPLACE

TC +6

CHECKG1 RELINT

CA NEWJOB

EXTEND

BZMF +6

TC CHANG1

INHINT

INDEX PIPINDEX

CS PIPAX

TS ZERONDX

INHINT

INDEX PIPINDEX

CA PIPAX

AD ZERONDX

EXTEND

BZF CHECKG1

INDEX PIPINDEX

CA PIPAX

INDEX RESULTCT

TS DATAPL

TC FINETIME

INDEX RESULTCT

TS DATAPL +1

## Page 422

INDEX RESULTCT

LXCH DATAPL +2

RELINT

ENDCHKG TC QPLACE

ZEROING TS L

TCF +2

ZEROING1 TS ZERONDX1

CAF ZERO

INDEX L

TS 0

INCR L

CCS ZERONDX1

TCF ZEROING1

TC Q

## Page 423

SETLOC IMUCAL3

BANK

ERTHRVSE DLOAD PDDL

SCHZEROS # PD24 = (SIN -COS 0)(OMEG/MS)

LATITUDE

COS DCOMP

PDDL SIN

LATITUDE

VDEF VXSC

OMEG/MS

STORE ERVECTOR

RTB

LOADTIME

STOVL TMARK

SCHZEROS

STORE ERCOMP1

RVQ

SETLOC IMUCAL

BANK

EARTHR ITA RTB # CALCULATES AND COMPENSATES EARTH RATE

S2

LOADTIME

STORE TEMPTIME

DSU BPL

TMARK

ERTHR

CALL

OVERFFIX

ERTHR SL VXSC

9D

ERVECTOR

MXV VAD

XSM

ERCOMP1

STODL ERCOMP1

TEMPTIME

STORE TMARK

AXT,1 RTB

ECADR ERCOMP1

PULSEIMU

GOTO

S2

EARTHR* EXTEND

QXCH QPLACES

TC INTPRET

CALL

EARTHR

PROUT EXIT

TC IMUSTLLG

TC QPLACES

## Page 424

SHOW EXTEND

QXCH QPLACE

SHOW1 CA POSITON

TS DSPTEM2 +2

CA VB06N98

TC BANKCALL

CADR GOFLASH

TC ENDTEST1 # V34

TC QPLACE # V33

TCF SHOW1

OC14400 OCT 14400

3990DEC = OMEG/MS

VB06N98 VN 0698

TESTTIME OCT 01602

DEC17 = ND1

OGCPL ECADR OGC

1SECX = 1SEC

DEC57 = VD1

XNBADR GENADR XNB

XSMADR GENADR XSM

OMEG/MS 2DEC .24339048

P11OUT TC BANKCALL

CADR MATRXJOB # RETURN TO P11

COUNT 02.COMST

BLOCK 2

FINETIME INHINT # RETURNS WITH INTERRUPT INHIBITED

EXTEND

READ LOSCALAR

TS L

EXTEND

RXOR LOSCALAR

EXTEND

BZF +4

EXTEND

READ LOSCALAR

TS L

+4 CS POSMAX

AD L

EXTEND

BZF FINETIME +1

EXTEND

READ HISCALAR

TC Q

## Page 425

# PROGRAM NAME-OPTIMUM PRELAUNCH ALIGNMENT CALIBRATION

# DATE- NOVEMBER 2 1966

# BY- GEORGE SCHMIDT IL 7-146 EXT. 126

# MOD NO 3

#

# FUNCTIONAL DESCRIPTION

#

# THIS SECTION CONSISTS OF PRELAUNCH ALIGNMENT AND GYRO DRIFT TESTS

# INTEGRATED TOGETHER TO SAVE WORDS. COMPASS IS COMPLETELY RESTART

# PROOFED EXCEPT FOR THE FIRST 30 SECONDS OR SO. PERFORMANCE TESTS OF

# THE IRIGS IS RESTART PROOFED ENOUGH TO GIVE 75 PERCENT CONFIDENCE THAT

# IF A RESTART OCCURS THE DATA WILL STILL BE GOOD. GOOD PRACTICE TO RECYCL

# WHEN A RESTART OCCURS UNLESS IT HAPPENS NEAR THE END OF A TEST-THEN WAIT

# FOR THE DATA TO FLASH.

#

# A RESTART IN GYROCOMPASS DURING GYRO TORQUING CAUSES PULSES TO BE LOST

# THE PRELAUNCH ALIGNMENT TECHNIQUE IS BASICALLY THE SAME AS IN BLOCK 1

# EXCEPT THAT IT HAS BEEN SIMPLIFIED IN THE SENSE THAT SMALL ANGLE APPROX.

# HAVE BEEN USED. THE DRIFT TESTS USE A UNIQUE IMPLEMENTATION OF THE

# OPTIMUM STATISTICAL FILTER. FOR A DESCRIPTION SEE E-1973. BOTH OF THESE

# ROUTINES USE STANDARD SYSTEM TEST LEADIN PROCEDURES. THE INITIALIZATION

# PROCEDURE FOR THE DRIFT TESTS IS IN THE JDC S. THE INITIALIZATION METHOD

# FOR GYROCOMPASS IS AN ERAS LOAD THEN A MISSION PHASE CALL.

# THE COMPASS ALIGNS TO Z DOWN, X DOWNRANGE, HAS THE CAPABILITY

# CHANGE AZIMUTH WHILE RUNNING, IS COMPENSATED FOR

# COMPONENT ERRORS, IS CAPABLE OF OPTICAL VERIFICATION (CSM ONLY).

#

# COMPASS ERASABLE LOAD REQUIRED

#

# 1- LAUNCHAZ-DP AZIMUTH IN REV FROM NORTH OF XSM DESIRED (NOM=.2)

# 2- LATITUDE-DP-OF LAUNCH PAD

# 3- AZIMUTH-DP-OF ZNB OF VEHICLE

# 4- IMU COMPENSATION PARAMETERS

# 5- AZ AND ELEVATION OF TARGETS 1,2 ****OPTIONAL****

#

# TO PERFORM AS PART OF COMPASS

#

# 1- OPTICAL VERIFICATION- V 65 E

# 2- AZIMUTH CHANGE- V 78 E

#

# SUBROUTINES CALLED

#

# DURING OPTICAL VERIFICATION (CSM ONLY) ESSENTIALLY ALL OF INFLIGHT ALIGN

# IS CALLED IN ONE WAY OR ANOTHER. SEE THE LISTING.

#

# NORMAL EXIT

#

# DRIFT TESTS- LENGTHOT GOES TO ZERO-RETURN TO IMU PERF TEST2 CONTROL

# GYROCOMPASS-MANY, SEE THE LISTING

#

# ALARMS

#

# 1600 OVERFLOW IN DRIFT TEST

## Page 426

# 1601 BAD IMU TORQUE ABORT

# 1602 BAD OPTICS DURING VERIFICATION-RETURN TO COMPASS CSM ONLY

#

# OUTPUT

#

# DRIFT TESTS- FLASHING DISPLAYS OF RESULTS-CONTROLLED IN IMU PERF TESTS 2

# COMPASS-PROGRAM MODE LIGHTS TELL YOU WHAT PHASE OF PROGRAM YOU ARE IN

# 01 INITIALIZING THE PLATFORM POSITION AND ERASABLE

# 02 GYROCOMPASSING

# 03 DOING OPTICAL VERIFICATION (CSM)

#

# DEBRIS

#

# ALL CENTRALS, ALL OF EBANK XSM

## Page 427

# MOST OF THE ROUTINES COMMON TO ALIGNMENT AND CALIBRATION APPEAR

# ON THE NEXT FEW PAGES.

COUNT 33/P02

EBANK= XSM

BANK 33

SETLOC IMUCAL

BANK

ESTIMS TC 2PHSCHNG # COMES HERE FROM IMU2

OCT 00075

OCT 00004 # TURN OFF GROUP 4 IF ON

RSTGTS1 INHINT # COMES HERE PHASE1 RESTART

CA TIME1

TS GTSWTLT1

CAF ZERO # ZERO THE PIPAS

TS PIPAX

TS PIPAY

TS PIPAZ

RELINT

CA 77DECML # ZERO ALL NECESSARY LOCATIONS

TS ZERONDX1

CA ALXXXZ

TC ZEROING

TC INTPRET

SLOAD

SCHZEROS

STOVL GCOMPSW -1

INTVAL +2 # LOAD SOME INITIAL DRIFT GAINS

STOVL ALX1S

SCHZEROS

STORE GCOMP

STORE DELVX # GCOMPZER SUBROUTINE NO LONGER NEEDED

EXIT

CCS GEOCOMP1 # NON ZERO IF COMPASS.

TC +2

TC SLEEPIE +1

TC INTPRET

CALL

ERTHRVSE

EXIT

CA LENGTHOT # TIMES FIVE IS THE NUM OF SEC ERECTING

TS ERECTIME

TC NEWMODEX

MM 02

TC BANKCALL # SET UP PIPA FAIL TO CAUSE ISS ALARM

## Page 428

CADR PIPUSE # COMPASS NEVER TURNS THIS OFF

TC ANNNNNN # END OF FIRST TIME THROUGH

## Page 429

# COMES HERE AT THE END OF EVERY ITERATION THROUGH DRIFT TEST OR COMPASS

# SET UP WAITLIST SECTION

SLEEPIE TS LENGTHOT # TEST NOT OVER-DECREMENT LENGTHOT

TC PHASCHNG # CHANGE PHASE

OCT 00135

CCS TORQNDX # ARE WE DOING VERTDRIFT

TC EARTHR* # TRUE TORQUE SOUTH GYRO

WTLISTNT TC CHKCOMED # SEE IF COMPASS OVER

TC SETGWLST

TC ENDOFJOB

SETGWLST EXTEND

QXCH MPAC # CALLED EVERY WAITLIST OR AZIMUTH CHANGE

INHINT

CS TIME1

AD GTSWTLT1

EXTEND

BZMF +2

AD NEGMAX # 10 MS ERROR OK

AD 1SECXT1 # 1 SEC FOR CALIBRATION, .5 SEC IN COMPASS

EXTEND

BZMF RIGHTGTS

WTGTSMPL TC TWIDDLE

EBANK= ALTIM

ADRES ALLOOP

TC MPAC

RIGHTGTS CAF FOUR # SET UP NEXT WAITLIST-ALLOW SOME TIME

TC WTGTSMPL # END OF WAITLIST SECTION

# STORE AND LOAD DATA SECTIONS FOR RESTART PROOFING

25DECML DEC 25

STOREDTA CAF 25DECML

TS MPAC

INDEX MPAC

CAE THETAX1

INDEX MPAC

TS RESTARPT

CCS MPAC

TCF STOREDTA +1

TC Q

LOADSTDT CAF 25DECML

TS MPAC

INDEX MPAC

CA RESTARPT

## Page 430

INDEX MPAC

TS THETAX1

CCS MPAC

TCF LOADSTDT +1

TC Q

# COMES HERE EVERY ITERATION BY A WAITLIST CALL SET IN SLEEPIE

ALLOOP CAE TIME1

TS GTSWTLT1 # STORE TIME TO SET UP NEXT WAITLIST.

ALLOOP3 CA ALTIM

TS GEOSAVE1

TC PHASCHNG

OCT 00115

ALLOOP1 CAE GEOSAVE1

TS ALTIM

CCS A

CA A # SHOULD NEVER HIT THIS LOCATION

TS ALTIMS

CS A

TS ALTIM

CAF ZERO

XCH PIPAX

TS DELVX

CAF ZERO

XCH PIPAY

TS DELVY

CAF ZERO

XCH PIPAZ

TS DELVZ

CAF 19DECML # 23 OCT

TC NEWPHASE

OCT 00005

SPECSTS CAF PRIO20

TC FINDVAC

EBANK= GEOSAVE1

2CADR ALFLT # START THE JOB

TC TASKOVER

## Page 431

# THIS IS PART OF THE JOB DONE EVERY ITERATION

ALFLT TC STOREDTA # STORE DATA IN CASE OF RESTART IN JOB

TC PHASCHNG # THIS IS THE JOB DONE EVERY ITERATION

OCT 00215

TCF +2

ALFLT1 TC LOADSTDT # COMES HERE ON RESTART

CCS GEOCOMP1

TC +2

TC NORMLOP

TC CHKCOMED # SEE IF PRELAUNCH OVER

TC BANKCALL # COMPENSATION IF IN COMPASS

CADR 1/PIPA

NORMLOP TC INTPRET

DLOAD

INTVAL

STOVL S1

DELVX

VXM VSL1

XSM

DLOAD DCOMP

MPAC +3

STODL DPIPAY

MPAC +5

STORE DPIPAZ

SETPD AXT,1

0

8D

SLOAD DCOMP

GEOCOMP1

BMN

ALWAYSG # DO A QUICK COMPASS

## Page 432

# NOW WE HAVE JUST THE CALIBRATION PARTS OF THE PROGRAM-NEXT PAGES

COUNT 33/COMST

ALCGKK SLOAD BMN

ALTIMS

ALFLT3 # NO NEW GAINS NEEDED

ALKCG AXT,2 LXA,1 # LOADS SLOPES AND TIME CONSTANTS AT RQST

12D

ALX1S

ALKCG2 DLOAD* INCR,1

ALFDK +144D,1

DEC -2

STORE ALDK +10D,2

TIX,2 SXA,1

ALKCG2

ALX1S

ALFLT3 AXT,1 # MEASUREMENT INCORPORATION ROUTINES

8D # AND GAIN UPDATES

DELMLP DLOAD* DMP

DPIPAY +8D,1

PIPASC

SLR BDSU*

9D

INTY +8D,1

STORE INTY +8D,1

PDDL DMP*

VELSC

VLAUN +8D,1

SL2R

DSU STADR

STORE DELM +8D,1

STORE DELM +10D,1

TIX,1 AXT,2

DELMLP

4

ALILP DLOAD* DMPR*

ALK +4,2

ALDK +4,2

STORE ALK +4,2

TIX,2 AXT,2

ALILP

8D

ALKLP LXC,1 SXA,1

CMPX1

CMPX1

DLOAD* DMPR*

ALK +1,1

DELM +8D,2

## Page 433

DAD*

INTY +8D,2

STORE INTY +8D,2

DLOAD* DAD*

ALK +12D,2

ALDK +12D,2

STORE ALK +12D,2

DMPR* DAD*

DELM +8D,2

INTY +16D,2

STORE INTY +16D,2

DLOAD* DMP*

ALSK +1,1

DELM +8D,2

SL1R DAD*

VLAUN +8D,2

STORE VLAUN +8D,2

TIX,2 AXT,1

ALKLP

8D

LOOSE DLOAD* PDDL* # EXTRAPOLATE SWAY VARIABLES

ACCWD +8D,1

VLAUN +8D,1

PDDL* VDEF

POSNV +8D,1

MXV VSL1

TRANSM1

DLOAD

MPAC

STORE POSNV +8D,1

DLOAD

MPAC +3

STORE VLAUN +8D,1

DLOAD

MPAC +5

STORE ACCWD +8D,1

TIX,1

LOOSE

AXT,2 AXT,1 # EVALUATE SINES AND COSINES

6

2

BOOP DLOAD* DMPR

ANGX +2,1

GEORGEJ

SR2R

PUSH SIN

## Page 434

SL3R XAD,1

X1

STORE 16D,2

DLOAD

COS

STORE 22D,2 # COSINES

TIX,2

BOOP

PERFERAS EXIT

CA EBANK7

EBANK= LAT(SPL)

TS EBANK

TC LAT(SPL) # GOTO ERASABLE ONLY TO RETURN

# CAUTION

#

# THE ERASABLE PROGRAM THAT DOES THE CALCULATIONS MUST BE LOADED

# BEFORE ANY ATTEMPT IS MADE TO RUN THE IMU PERFORMANCE TEST

EBANK= LENGTHOT

ONCEMORE CCS LENGTHOT

TC SLEEPIE # TEST NOT OVER SET UP NEXT WAITLIST

CCS TORQNDX

TCF +2

TC SETUPER1

CA CDUX

TS LOSVEC +1 # FOR TROUBLESHOOTING POSNS 2$4 VD

SETUPER1 TC INTPRET # DRIFT TEST OVER

DLOAD PDDL # ANGLES FROM DRIFT TEST ONLY

ANGZ

ANGY

PDDL VDEF

ANGX

VCOMP VXSC

GEORGEJ

MXV VSR1

XSM

STORE OGC

EXIT

TORQINCH TC PHASCHNG

OCT 00005

CA OGCPL

TC BANKCALL

CADR IMUPULSE

TC IMUSTLLG

CCS TORQNDX # + IF IN VERTICAL DRIFT TEST

TC VALMIS # VERT DRIFT TEST OVER

TC INTPRET

## Page 435

CALL # SET UP ERATE FOR PIP TEST OR COMPASS

ERTHRVSE

EXIT

TC TORQUE # GO TO IMU2 FOR A PIPA TEST AND DISPLAY

SOMEERR TC ALARM

OCT 1600

TC +3

SOMERR2 TC ALARM

OCT 1601

TC PHASCHNG

OCT 00005

TC ENDTEST1

# THE FAMOUS MAGIC NUMBERS OF SCHMIDT ARE NOW PART OF AN ERASABLE LOAD.

DEC585 OCT 02222 # 1170 B+14 ORDER IS NOW IMPORTANT

SCHZEROS 2DEC .00000000

2DEC .00000000

OCT 00000

ONEDPP OCT 00000

OCT 00001 # ABOVE ORDER IS IMPORTANT

INTVAL OCT 4

OCT 2

DEC 144

DEC -1

SOUPLY 2DEC .93505870 # INITIAL GAINS FOR PIP OUTPUTS

2DEC .26266423 # INITIAL GAINS/4 FOR ERECTION ANGLES

77DECML DEC 77

ALXXXZ GENADR ALX1S -1

# GYROCOMPASS PORTIONS FINISH THIS LOG SECTION

COUNT 33/P01

# INITIALIZATION SECTION

GTSCPSS CAF ONE # CALLED BY V37.

TS GEOCOMP1 # THIS IS THE LEAD IN FOR COMPASS.

## Page 436

CA 1/PIPAGT

TS 1/PIPADT

NXXTENN CA BIT8

TS LENGTHOT

CAF 1/2SECX # COMPASS IS A .5 SEC LOOP

TS 1SECXT1

CAF ONE

TS PREMTRX1

TS PERFDLAY +1

CAF ZERO

TS PERFDLAY

EXTEND

DCA LUNCHAZ1

DXCH NEWAZ1

EXTEND

DCA LUNCHAZ1

DXCH OLDAZMTH

SETUPGC CA DEC17

TS ZERONDX1

CA XSMADR

TC ZEROING

TC POSN17C

TC GEOIMUTT # GO TO IMU2 FOR FURTHER INITIALIZATION

POSN17C EXTEND # COMPASS POSITION Z DOWN, X DOWNRANGE

QXCH QPLACE # FROM NORTH IN REVOLUTIONS + CLOCKWSE

CS HALF # ALL THIS TO INITIALIZE MATRIX

TS ZSM

TC INTPRET

DLOAD PUSH

NEWAZ1

SIN

STORE XSM +4

STODL YSM +2

COS

STORE YSM +4

DCOMP

STORE XSM +2

EXIT

TC QPLACE

# JOB DONE EVERY ITERATION THROUGH COMPASS PROGRAM. SET BY TASK ALLOOP

COUNT 33/P02

ALWAYSG DLOAD* DSU* # COMPASS AND ERECT

DPIPAY +8D,1

FILDELV1 +8D,1

## Page 437

DMPR DAD*

GEOCONS1

FILDELV1 +8D,1

STORE FILDELV1 +8D,1

DAD*

INTVEC1 +8D,1

STORE INTVEC1 +8D,1

DMPR DAD*

GEOCONS2

FILDELV1 +8D,1

DMPR PUSH

GEOCONS5

TIX,1 SLOAD

ALWAYSG

ERECTIM1

BZE DLOAD

COMPGS

THETAN1 +2

DSU STADR

STODL THETAN1 +2 # ERECTION ONLY.

BDSU

THETAN1 +4

STORE THETAN1 +4

GOTO

ADDINDRF

COMPGS DLOAD DAD # COMPASS

THETAN1

FILDELV1

STODL THETAN1

FILDELV1

DMPR BDSU

GEOCONS3

THETAN1 +4

STODL THETAN1 +4

FILDELV1 +4

DMPR BDSU

GEOCONS3

THETAN1 +2

PDDL DMPR

INTVEC1 +4

GEOCONS4

BDSU STADR

STORE THETAN1 +2

ADDINDRF EXIT

ENDGTSAL CCS LENGTHOT # IS 5 SEC OVER-THE TIME TO TORQ PLATFORM

TC SLEEPIE # NO-SET UP NEXT WAITLIST CALL FOR .5 SEC

TC CHKCOMED

CCS LGYRO # YES BUT ARE GYROS BUSY

## Page 438

TCF SLEEPIE +1 # BUSY-GET THEM .5 SECONDS FROM NOW

LASTGTS TC INTPRET

VLOAD

ERCOMP1

STODL THETAX1

TMARK

STORE ALK

EXIT # PREVIOUS SECTION WAS FOR RESTARTS

RESTAIER TC PHASCHNG

OCT 00275

TC INTPRET # ADD COMPASS COMMANDS INTO ERATE

VLOAD MXV

THETAN1

XSM

VSL1 VAD

THETAX1

STODL ERCOMP1