Pershing
Ia
System Description
June
1974
OR
13,149
MARTIN MARIE'ITA AEROSPACE
ORLANDO DIVISION
T h e P e r s h i n g Weapon y s t e m constitutes one of t h e United S t a t e ? s m a j o r nuclear d e t e r r e n t f o r c e s , The s y s t e m is deployed o p e r a t iy in Europe and continues t o
s t a n t i a l contribution t o t h e balance of r and t h e maintenance of peace,
m
I he c u r r e n t v e r s i o n i s the P e r s h i n g a ) which was derived by a n evoiutionary p r o c e s s of continuous i m p r m e n t s t o the initial s y s t e m iguralion, T h i s book provides a functional d e s c r on of t h e P e r s h i n g la m a j o r ipment i t e m s ,
T h i s book was under t h e d i r e c t i o n of Ro e r t L. Ferguson,
System E n g i n e e r i nd was composed, edited, and for atted by Charles
E.
Waters, P e r s h i n g P r e s e n t a t i o n s .Reprinted by Army Field
. . .
Chapter One.
G e n e r a l S y s t e m D e s c r i p t i o n 1. . .
P e r s hing I a F i r i n g B a t t e r y Components 2 M i s s i l e. . . e . e . ~ . . .
.
3. . .
E r e c t o r - Launcher 3. . .
P r o g r a m m e r - T e s t Station and P o w e r Station 4
. . .
Azimuth Laying Set 4
. . .
B a t t e r y C o n t r o l C e n t r a l 6. . .
Radio T e r m i n a l Set 6 R e a r A r e a Support Components. . .
7. . .
S y s t e m Components T e s t Station 7. . .
P o w e r Station Equivalent 7. . .
Support Shops 8. . .
M i s s i l e S e c t i o n C o n t a i n e r s 8. . .
Chapter Two.
T h e i s s i l e 9 A i r f r a m e . . . . . . . . . . . e . . . . . . . . . . . . . . . . . e . e e e . . . . .. . .
9 Warhead Section. . .
9. . .
G u i d a n c e a n d C o n t r o l S e c t i o n 11. . .
o r Section 12 r Section. . .
12. . .
P r o p u l s i o n 1-2 P r o p e l l a n t. . .
. . .
F i r s t Stage Motor Assembly and C a s e
. . .
o t o r Assembly and C a s e 14
u l a t i o a
. . . a * . . .
. . .
. . .
Guidance and C o n t r o l. . .
Guidance Scheme. . .
Control Scheme. . .
entati.cn. . .
ntation.
.
.
. . .
Referenee S y s t e m. . .
n t r o l Computer. . .
Actuator S y s t e m. . .
E l e c t r i c a l. . .
B a t t e r y. . .
Static I n v e r t e r. . .
ain D i s t r i b u t o r. . .
High E n e r g y F i r i n g Units. . .
P o w e r D i s t r i b u t o r. . .
Additional Equipment. . .
e r T h r e e.
E r e c o r - l a u n c h e r. . .
e r A s s e m b l y ernbly. . .
. . .
Azimuth Ring A s s e m b l y a s t. . .
on Handling Device. . .
i t A s s e m b l y. . .
tions. . . * . . m e . .
. . .
. . .
. . .
. . .
. . .
. . .
a d s. . .
. . .
Associated Corn onents
. . .
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Booms. . . * . . . * . . .
. . .
i s s i l e C r a d l e. . . .
Retaining Ring Half
. . .
War head Section Handling eviee
. . . .
.
. . .
Control Box. . .
r a u l i e C o n t r o l P a n e l. . .
Hydrauli o r E r e c t i o nlock and Associated Corn onents
. . .
T r a n s p o r t e r A s s e b l y . . . * e . . . s . e . . e e e e *. . .
P h y s i c a l Data. . .
Functional Data. . .
Leveling S y s t e mL e v e l S e n s o r
. . .
6 3 E l e c t r i c a l C o n t r o l C i r c u i t r y. . .
6 3 anual D r i v e. . .
63. . .
E r e c t i o n S y s t e m 64. . .
Hydraulic E r e c t i o n A s s e m b l i e s 64. . .
Hydraulic Accumulator. 64. . .
P i l o t v a l v e 64. . .
S e l e c t o r Valve 64. . .
E r e c t i o n Manifold and Associated Components 64. . .
Hydraulic A c t u a t o r s 64. . .
E l e c t r i c P u m p 64. . .
anual P u m p 66. . .
y d r a u l i c S y s t e m Oil Tank 66 Mechanical E r e c t i o n A s s e m b l i e s. . .
67 Azimuth Ring A s s e m b l y. . .
67 Booms. . .
67 M i s s i l e c r a d l e. . .
67Retaining Ring Half
. . .
69Uplock and Associated Components
. . .
69Cable Mast A s s e m b l y
. . .
69 Azimuth Ring A s s e m b l y C l a m p R e l e a s e e c h a n i s m. . .
69 Chapter F o u r-
P r o g r a m m e r - T e s t Station. . .
;. . .
72 Shelter. . .
73. . .
Computer 75 Adapter. . .
76. . .
Operations C o n t r o l Function 77. . .
Command and Monitoring Function 77. . .
P l a t f o r m Alignment Function 79 AC /DC Stimuli Function. . .
79. . .
M e a s u r e m e n t s Function 79 P r e s e t t i n g Function. . .
79. . .
Modules 79 Adapter F i l t e r A s s e m b l y. . .
79. . .
Adapter E l e c t r i c a l Equipment Rack 8 v o l t a g e M e a s u r e m e n t. . .
81. . .
Stimulus Voltage 81 I n v e r t e r F r e q u e n c y. . .
8 1 Synchro P r e s e t. . .
81 Remote F i r e Box. . .
82 Console. . .
8 2 Azimuth Laying Control P a n e l Assembly. . .
8 3. . .
i t o r P a n e l Assembly
. . .
Assembly
Tape Reader
. . .
Countdown Control P a n e l Assembly. . .
8 3Utility P a n e l A s s e m b l y
. . .
. . .
T e l e p r i n t e r. . .
. . .
.
Chapter F i v e Power Station
. . .
G e n e r a l Description. . .
G a s Turbine Engine Gearbox. . .
. . .
High P r e s s u r e Air System
. . .
Air Cycle Conditioning System
. . .
DC Power System. . .
AC Power System. . .
h e r Subsystems. . .
.
Chapter Six Azimuth Laying Equipment Set
. . .
Equipment Description
. . .
~ o r i z o n t a l / V e r t i c a l Laying Theodolite
. . .
Orienting Station Theodolite
. . .
Orienting Line T a r g e t
. . .
Azimuth Laying Control Box
. . .
Miscellaneous Equipment. . .
Laying Methods General. . .
. . .
E r e c t and F i r e Mode. . .
V e r t i c a l Laying Mode. . .
.
Chapter Seven B a t t e r y Control C e n t r a l
. . .
Physical Description. . .
E l e c t r i c a l Power. . .
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Chapter Eight Communications
. . .
ANiTRC.80. Radio T e r m i n a l Set
. . .
ANITRC- 133A. Radio T e r m i n a l Set
. . .
.
Chapter Nine Ground Networks
. . .
.
Chapter T e n System Components T e s t Station
. . .
E x t e r i o r Description. . .
SCTS Major Assemblies. . .
Major PTS Assemblies. . .
Major SCTS Consoles and Assemblies. . .
Assembly T e s t e r. . .
Pneumatic T e s t Console. . .
Distribution Console. . .
Cable Entry P a n e l s. . .
Equipment Storage. . .
AC /DC Differential Voltmeter and Oscilloscope
. . .
t e r Eleven
.
ARS/SLA. . .
Automatic Reference System. . .
Azimuth Reference Unit
. . .
Reference Assembly
. . .
Translating Asse ly
. . .
a . ~ ~ . . ~ ~ ~ e * . ~ e e * * ~ * ~ e ~ e o ~ e . . ~ ~ * * * * ~ ~ ~ e * . ment. . .
ueritial Launch A e r. . .
de. . .
1. . .
r i e a l Section. . .
neurnatic Section. . .
n s. . .
. . .
Typical P e r s h i n g Flight Scenario
. . .
P e r s h i n g Ia F i r i n g B a t t e r y Components
. . .
Surface Attack Guided Missile XMGM-31A ( P e r s h i n g Missile). . .
T r a c t o r with Erector-Launcher. . .
P r o g r a m m e r - T e s t StationlPower Station. . .
Azimuth Laying Set. . .
B a t t e r y Control C e n t r a l
. . .
Radio T e r m i n a l Set AN/TRC-80
. . .
S y s t e m Components T e s t StationPower Station Equivalent
. . .
. . .
Typical R e p a i r Shop. . .
Typical Maintenance Shop and Supply Van
M i s s i l e Section Shipping and Storage Containers
. . .
. . .
P e r s h i n g M i s s i l e A e r o and S t r u c t u r a l ComponentsP e r s h i n g M i s s i l e Sections
. . .
. . .
P e r s h i n g F i r s t and Second Stage Motors. . .
F i r s t Stage Motor Section. Inboard P r o f i l e. . .
Second Stage Motor Section. Inboard P r o f i l e. . .
Guidance and Control Section. . .
Guidance and Control S y s t e m Functional Schematic
. . .
Missile Guidance Coordinates and E r r o r s. . .
M i s s i l e Attitude E r r o r s
. . .
Missile Response t o Attitude E r r o r s. . .
Missile Coordinate S y s t e m. . .
Pitch/Yaw Loops R o l l h o p. . .
. . .
Steering Scheme. . .
e r t i a l System. . .
i s s i l e Axes Orientation ST- 120 Gimbals. . .
AB-5 Gyroscope. . .
The P e r s h i n g Ia Weapon System i s a t a c t i c a l , mobile b a l l i s t i c m i s s i l e s y s t e m p o s s e s s i n g the capability t o respond effectively to any n u c l e a r o r m a j o r nonnuclear t h r e a t to the United S t a t e s o r i t s a l l i e s .
The s y s t e m i s c o m p r i s e d of all f i r i n g b a t t e r y components r e q u i r e d to conduct launch operations a s well a s equipment n e c e s s a r y f o r r e a r a r e a s u p p o r t and m a i n t e - nance functions.
In i t s b a s i c s c e n a r i o , the m i s s i l e d e l i v e r s a n u c l e a r warhead to p r e s e l e c t e d t a r g e t out to a range of 4C0 m i l e s f r o m the launch point ( F i g u r e 1-1). When the m i s s i l e is f i r e d , the f i r s t s t a g e r o c k e t m o t o r i s ignited, P e r s h i n g liftoff o c c u r s and the m i s s i l e begins a p r e d e t e r m i n e d pitchover m a n e u v e r toward t h e t a r g e t . When f i r s t s t a g e b u r n - out is achieved t h e m i s s i l e e n t e r s a c o a s t period. At the end of t h e c o a s t period, f i r s t s t a g e s e p a r a t i o n o c c u r s and the second s t a g e rocket m o t o r i s ignited to a c c e l e r a t e the r e m a i n i n g m i s s i l e s e c t i o n s along the flight path. During second s t a g e burn, t h e guid- a n c e computer constantly computes the m i s s i l e ' s velocity and displacement. When the p r o p e r values of attitude, r a n g e , and velocity have been attained a t h r u s t t e r m i n a t i o n signal i s applied, second s t a g e s e p a r a t i o n o c c u r s , and the warhead i s spun a t 32 r p m t o s t a b i l i z e i t s f o r w a r d motion a s it continues on a b a l l i s t i c t r a j e c t o r y t o the t a r g e t .
SEPARATION
-
I BURNING PHASEPer
a
The v a r i o u s components r e q u i r e d t o conduct launch o p e r a t i o n s a t the firing b a t t e r y a r e the m i s s i l e , e r e c t o r - l a u n c h e r , p r o g r a m m e r - t e s t station and power station, azimuth laying s e t , b a t t e r y control c e n t r a l , and the r a d i o t e r m i n a l s e t . A l l of t h e s e components a r e mounted on wheeled vehicles ( F i g u r e 1 - 2 1 except f o r the azimuth l a y - ing s e t which i s t r a n s p o r t e d on a 2 1/2 ton c a r g o vehicle and unloaded f o r use.
T h e P e r s h i n g m i s s i l e ( F i g u r e 1- 3) is a two-stage, s u r - f a c e - t o - s u r f a c e b a l l i s t i c weapon c a able of engaging t a r g e t s
m i l e s . It has a n a l l - i n e r t i a l guidance s y s t e m e s t h e n u c l e a r warhead in a p r e s e l e c t e d b a l l i s t i c t r a j e c t o r y by using d a t a i n s e r t e d into t h e guidance and con- t e r b e f o r e liftoff. Once t h e m i s s i l e is a i r b o r n e ,
etely f r e e of ground control and t h e r e f o r e un- affected by a l l known methods of guidance countermeasures.
Designed f o r simplified t r a n s p o r t a t i o n and f a s t e r e c t i o n and f i r i n g of the P e r s h i n g m i s s i l e , the e r e c t o r - l a u n c h e r ( F i g u r e 1-41 i s capable of paved road o r c r o s s country t r a v e l . At t h e firing s i t e automatic e r e c t i o n and leveling contribute t o a v e r y rapid r a t e of f i r e . The e r e c t o r - l a u n c h e r ( E L ) with m i s s i l e aboard i s towed by the XM757
t r a c t o r . The e r e c t o r - l a u n c h e r with m i s s i l e aboard can a l s o be t r a n s p o r t e d by C-130, (2-133, and C - 1 4 1 a i r c r a f t .
r o g r a m m e r - t e s t station own in F i g u r e 1 - 5 i s
6 5 6 vehicle and f e a - t u r e s rapid m i s s i l e checkout and countdowns, with complete c o m - puter control, and automatic s e l f - t e s t and malfunction isolation. Ad- ditionally, the P T S p e r f o r m s t e s t s that s i m u l a t e a i r b o r n e m i s s i l e op- e r a t i o n , p r o g r a m s the t r a j e c t o r y of the m i s s i l e , and controls the firing sequence. Modern e l e c t r o n i c s pack- aging, featuring plug-in m i c r o m o d - ules, i n c r e a s e s maintainability and allows the P T S o p e r a t o r to p e r f o r m 80 p e r c e n t of all r e p a i r s at the f i r - ing position. T h e power station, which provides the p r i m a r y e l e c t r i
-
e a l and pneumatic power f o r the m i s s i l e and ground support equip- ment a t the firing position, i s t r a n s - ported on the s a m e vehicle.The azimuth laying s e t ( F i g u r e 1 - 6 ) , which i s s i m i l a r in design and function to standard surveying equipment, i s used to align the m i s s i l e i n e r t i a l guiance s y s t e m t o the c o r r e c t t a r g e t azimuth. All of t h e equipment i s s t o r e d in two p r o t e c t i v e c o n t a i n e r s and c a r r i e d aboard a n a u x i l i a r y equipment vehicle.
T o control the P e r s h i n g
e n s u r e n u c l e a r safety, the b a t t e r y c o m - m a n d e r m o n i t o r s and d i r e c t s f i r i n g s i t e a c t i v i t i e s by maintaining communications with a i l units f r o m a firing b a t t e r y con-
is a l s o linked with other b a t t e r i e s and ion h e a d q u a r t e r s f o r positive c o m -
T o c o n t r o l and coordinate firing bat- t e r y o p e r a t i o n s , s e v e r a l communication links a r e established with higher head- q u a r t e r s . Battalion communications a r e maintained with the r a d i o t e r m i n a l s e t ,
g u r e 1-8). The radio d e r - provides voice and t e l e - type communications between m i s s i l e firing units and higher h e a d q u a r t e r s . During t r a v e l the inflatable antenna is s t o r e d in a r e c e s s e d s p a c e in the roof of the RTS. Like the o t h e r e l e m e n t s of the firing b a t t e r y the RTS i s c a r r i e d on an
M6 56 vehicle.
Radio t e r m i n a l s e t , A N / T R C - ~ ~ ~ A , i s a l s o used at the firing s i t e a s the p r i m a r y QRA (Quick Reaction Alert) r e l e a s e m e s - s a g e s y s t e m . T h e A N / T R C - ~ ~ S A i s gov- e r n m e n t furnished equipment.
e l e m e n t s of the s y s t e m a r e maintained in a s t a t e of combat r e a d i n e s s by Lie r e a r a r e a s u p p o r t e
The s y s t e m components t e s t station (SCTS} i s used t o p e r f o r m r e a r a r e a mainte- nance of the P e r s h i n g s y s t e m ( F i g u r e 1-91. Housed in a mobile c e n t e r , the SCTS utilizes a c o m p u t e r and tape p r o g r a m s f o r t e s t i n g m i s s i l e sections, a s s e m b l i e s , c a r d s , r e l a y s , and modules f r o m the guided m i s s i l e and a s s o c i a t e d ground support equipment. Diagnostic tape p r o g r a m s a r e a l s o provided f o r verification and troubleshooting of m a j o r SCTS a s s e m b l i e s . The SCTS contains a dismounted P T S and h a s f a c i l i t i e s
whereby one m i s s i l e guidance section can be t e s t e d and another r e p a i r e d simultaneously under controlled t e m p e r a t u r e conditions. P o w e r f o r the SCTS o r i g i n a t e s f r o m the power
T h e power s t a t i o n equivalent (PSE) provides the s a m e outputs a s the firing b a t t e r y power station but i s capable of m o r e sustained o p e r a - tion. C o m p r i s e d of two t r a i l e r mounted power s t a t i o n s and one f a c i l i t i e s distribution t r a i l e r
F i g u r e 1-10), the PSE f u r n i s h e s a l l the power r e q u i r e d f o r r e a r a r e a checkout.
S e v e r a l shops and s e m i t r a i l e r vans ( F i g u r e s 1-11 and 1-12) a r e assigned to the r e a r a r e a t o provide f a c i l i t i e s f o r e l e c t r i c a l and mechanical maintenance and r e p a i r , p a r t s s t o r a g e , and offices f o r d i r e c t i o n and c o n t r o l of d i r e c t support and g e n e r a l s u p - p o r t maintenance functions.
S e p a r a t e r e u s a b l e shipping and s t o r a g e c o n t a i n e r s ( F i g u r e 1-13) a r e provided f o r e a c h of the four m i s s i l e s e c t i o n s . The c o n t a i n e r s p r o t e c t the m i s s i l e s e c t i o n s f r o m the e f f e c t s of e x c e s s i v e vibration, a b n o r m a l handling, and intolerable a t m o s p h e r i c conditions.
P e r s h i n g i s a two s t a g e , solid propellant b a l l i s t i c m i s s i l e ( F i g u r e 2-1). T h e m i s s i l e a i r f r a m e is 415.27 i n c h e s long, h a s a m a j o r d i a m e t e r of 40 i n c h e s , and weighs approxi- m a t e l y 1 0 , 0 0 0 pounds. Monocoque in construction, the m i s s i l e h a s an o u t e r skin a s s e m - bled t o t r a n s v e r s e r i n g s f o r r i g i d i t y d u r i n g flight and ground handling. Splice r i n g s m a k e w a r h e a d s e c t i o n s , guidance and c o n t r o l s e c t i o n s , and second and f i r s t s t a g e m o t o r s e c t i o n s c o m p l e t e l y i n t e r c h a n g e a b l e . F l i g h t c o n t r o l is m a i n t a i n e d by using s e t s of t h r e e a i r and jet v a n e s a t the aft end of e a c h m o t o r s e c t i o n ; t h e s e v a n e s a r e mounted 1 2 0 d e - g r e e s a p a r t a r o u n d t h e m o t o r p e r i p h e r y . S p e c i f i c l o c a t i o n s along the m i s s i l e longitudi- n a l l i n e a r e m e a s u r e d i n i n c h e s f r o m s t a t i o n 100, a point 3.99 i n c h e s i n f r o n t of the m i s - s i l e n o s e . P e r s h i n g i s s t r u c t u r a l l y and functionally divided into four s e c t i o n s : the w a r - head s e c t i o n , the g u i d a n c e and c o n t r o l s e c t i o n , and the second and f i r s t s t a g e m o t o r s e c - t i o n s ( F i g u r e 2-2).
T h e w a r h e a d s e c t i o n is c o n s t r u c t e d on an a l u m i n u m s u b s t r u c t u r e with an ablative type p l a s t i c s h e l l of v a r y i n g t h i c k n e s s . T h i s s h e l l is f a b r i c a t e d f r o m l a y e r s of pheonolic- i m p r e g n a t e d , r a n d o m o r i e n t e d a s b e s t o s t a p e , c u r e d i n t o a homogeneous s t r u c t u r e u n d e r heat and high p r e s s u r e . T h e s u r f a c e is h a r d and b r i t t l e with ablative c h a r a c t e r i s t i c s .
In t h e f i n a l p h a s e of flight, t h e w a r h e a d s e c t i o n b e c o m e s a r e e n t r y body e x p o s e d to the heating e f f e c t s of high s p e e d p a s s a g e t h r o u g h a t m o s p h e r e . T h e v a r y i n g t h i c k n e s s of the s k i n is designed in a c c o r d a n c e with the r a t e of ablation experienced by the r e e n t r y body when s u b j e c t e d t o t h e s e heating e f f e c t s . Nose cone, c e n t e r , and aft s u b s e c t i o n s f o r m the w a r h e a d s e c t i o n .
1 2 PAD, AIR VANE ( 3 )
13 SHELL, BODY, F I R S T STAGE
1 4 ROCKET MOTOR ASSEMBLY, F I R S T STAGE
15 J E T VANE ( 3 ) 1 6 FLAME S H I E L D ( 3 ) 17 BOLT, MACHINE ( 2 1 ~ - , i s AIR VANE ( 3 ) 19 PAD, A I R VANE ( 3 ) 2 0 BAND, S E C T I O N ( 4 ) 21 SHELL, BODY, SECOND STAGE
2 2 ROCKET MOTOR ASSEMBLY, SECOND STAGE
23 CASE VENTING - - - - SYSTFM
2 4 THRUST REVERSAL PORT COVER ( 3 )
25 THRUST REVERSAL PORT ( 3 ) 2 6 BOLT. MACHINF ( 7 1 2 7 CONNECTING L I N ~ S ' ( P ) 2 8 BASE STRUCTURE ASSEMBLY 2 9 COVER ASSEMBLY 30 BOLT, MACHlNE ( 2 ) BODY SECTION, GUIDED M I S S I L E , WARHEAD ( X M 2 8 ) BODY SECTION, GUIDED M I S S I L E , GUIDANCE AND CONTROL ( X M 9 2 ) BODY SECTION, GUIDED M I S S I L E , SECOND STAGE ( X M 1 0 2 )
T h e n o s e cone s u b s e c t i o n is a plastic cone a s s e m b l e d with a n o n s t r u c t u r a l nose l i n e r having an aluminum s p l i c e ring a t the aft end. The c e n t e r subsection i s a double-cone f r u s t u m shaped a s s e m b l y with the p e r i p h e r a l s h e a r type of aluminum s p l i c e r i n g s located at i t s f o r w a r d and aft e n d s . An additional f r a m e with longitudinal s t i f f e n e r s placed r a d i - a l l y i n t h e aft end is used to s u p p o r t the w a r h e a d and r e l a t e d n e t w o r k s . T h e aft s u b s e c - tion, s i m i l a r i n c o n s t r u c t i o n t o t h e c e n t e r s u b s e c t i o n , is mated to the c e n t e r subsection with an aluminum s p l i c e r i n g . An insulated, domed aluminum bulkhead, located at the aft end of t h i s s u b s e c t i o n , i s the c l o s u r e f o r the warhead s e c t i o n . Both the spin s y s t e m and c o v e r plate a r e mounted on t h i s bulkhead. A s p l i c e r i n g a s s e m b l y c o u p l e s the w a r - head s e c t i o n with the guidance and c o n t r o l s e c t i o n . T h e s p l i c e r i n g is held t o g e t h e r by e x p l o s i v e bolts to p e r m i t inflight s e p a r a t i o n of the two s e c t i o n s .
T h e guidance and c o n t r o l s e c t i o n i s a two p i e c e , m e t a l c o n i c a l , f r u s t u m shaped s t r u c - t u r e p r e s s u r i z e d t o p e r m i t t e m p e r a t u r e and p r e s s u r e c o n t r o l f o r a i r b o r n e guidance and c o n t r o l equipment. T h e two p i e c e s a r e the c o v e r f o r w a r d s e c t i o n ) and the b a s e
tion), A s p l i c e r i n g a s s e m b l y j o i n s the guidance and c o n t r o l s e c t i o n and second s t a g e m o t o r s e c t i o n . Conventional b o l t s a r e used t o hold the s p l i c e r i n g t o g e t h e r s i n c e no i n - flight s e p a r a t i o n o c c u r s at t h i s i n t e r f a c e . Support b r a c k e t s f o r the c o m p o n e n t s and w i r i n g , and the a i r d u c t s and manifold f o r the ST-120 a i r s u p p l y a r e i n t e g r a l p a r t s of the i n t e r n a l s t r u c t u r e .
T h r e e m a j o r s t r u c t u r a l p a r t s c o m p r i s e the s e c o n d s t a g e m o t o r s e c t i o n : the second s t a g e m o t o r c a s e , the f o r w a r d m o t o r a d a p t e r , and the aft c o n t r o l s package.
T h e hydrospun, high s t r e n g t h D6AC s t e e l c a s e s e r v e s a d u a l p u r p o s e in being both the p r o p e l l a n t c o n t a i n e r a r d the o u t e r s k i n of the m i s s i l e in the c e n t e r of the s e c t i o n . T h e f o r w a r d m o t o r a d a p t e r , a t t a c h e d t o the domed end of the m o t o r c a s e , a d a p t s to the guidance and c o n t r o l s e c t i o n by a V-band s p l i c e r i n g . T h e f o r w a r d m o t o r a d a p t e r is 4
i n c h e s i n d i a m e t e r and 19.93 i n c h e s wide.
S t r u c t u r a l s u p p o r t between t h e second s t a g e m o t o r c a s e and t h e f i r s t s t a g e m o t o r Fee-
tion is provided by the aft c o n t r o l s package which h o u s e s the a i r vane and jet vane a s s e m - b l i e s , t h r e e h y d r a u l i c a c t u a t o r units, a f l a m e s h i e l d , and a i r vane pads.
In addition t o the i n t e r n a l s t r u c t u r e , a conduit c o v e r and c a s e venting shaped c h a r g e s a r e attached t o the o u t e r s k i n of the m i s s i l e .
Like the second s t a g e , the f i r s t s t a g e i s c o m p r i s e d of t h r e e m a j o r s t r u c t u r a l p a r t s : f i r s t s t a g e m o t o r c a s e , f o r w a r d m o t o r a d a p t e r , and aft c o n t r o l s package. M a t e r i a l and c o n s t r u c t i o n t e c h n i q u e s used f o r the f i r s t and s e c o n d s t a g e m o t o r c a s e s a r e the s a m e ; h o w e v e r , the f i r s t s t a g e is l a r g e r and h o u s e s no i m p u l s e c o n t r o l e q u i p m e n t . T h e f i r s t s t a g e m o t o r c a s e a l s o s e r v e s a s the o u t e r m i s s i l e s k i n i n the c e n t e r portion of the s e c - tion.
T h e f o r w a r d m o t o r a d a p t e r is provided to adapt the f i r s t s t a g e m o t o r s e c t i o n t o the second s t a g e . T h e s p l i c e r i n g V-band, a f o u r s e g m e n t band having explosive links with d e t o n a t o r a s s e m b l i e s adapted t o i t , m a t e s the s e c t i o n s .
S t r u c t u r a l s u p p o r t between the f i r s t s t a g e m o t o r c a s e and the a z i m u t h r i n g of the e r e c t o r - l a u n c h e r is provided by the f i r s t s t a g e aft c o n t r o l s package. It a l s o p r o v i d e s s u p p o r t and housing f o r the t h r e e h y d r a u l i c actuation s y s t e m s , f l a m e s h i e l d , a i r and jet v a n e s , f o r w a r d a i r vane pads, and the t a i l plug a s s e m b l y . In addition to the i n t e r n a l
s t r u c t u r e , a conduit c o v e r i s e x t e r n a l l y mounted between the f o r w a r d m o t o r a d a p t e r and the aft c o n t r o l package.
T h e p r i m a r y function of t h e r o c k e t m o t o r s ( F i g u r e 2-3) i s to p r o p e l the P e r s t l i n g m i s s i l e f r o m liftoff to f i r s t s t a g e s e p a r a t i o n and f r o m second s t a g e ignition to cutoff. At t h i s t i m e the w a r h e a d s e c t i o n i s s e p a r a t e d f r o m the guidance and c o n t r o l and second s t a g e s e c t i o n s and b e c o m e s a f r e e b a l l i s t i c m i s s i l e .
Pro
hifotor p r o p e l l a n t used is of a composite c a s t f o r m u l a using aluminum powder a s the fuel, a m m o n i u m p e r c h l o r a t e a s the o x i d i z e r , and polybutadiene a c r y l i c acid (PBAA) a s the b i n d e r ( t h e PBAA a l s o s e r v e s a s a fuel). Both m o t o r s have an i n t e r n a l burning c y l i n d r i c a l c o r e which t e r m i n a t e s in a d o m e shaped s l o t at the head end. Since PBAA b i n d e r i s b a s i c a l l y a s y n t h e t i c r u b b e r , t h i s f o r m u l a and configuration r e s i s t c r e e p o r
T h e f i r s t s t a g e m o t o r a s s e m b l y c o n s i s t s of o n e s o l i d p r o p e l l a n t r o c k e t m o t o r with i n t e g r a l f o r w a r d a d a p t e r , one V s p l i c e band, two f i r i n g unit a s s e m b l i e s , t h r e e h y d r a u - l i c p a c k a g e s , t h r e e a i r v a n e s , t h r e e j e t v a n e s , t h r e e a i r v a n e p a d s , f l a m e s h i e l d , i n i t i - a t o r s , d e t o n a t o r s , s e p a r a t i o n l i n k s , t o r q u i n g l i n k s , e l e c t r i c a l n e t w o r k s h a r n e s s e s , and e x t e r n a l conduit c o v e r ( F i g u r e 2 -4).
A
hydrospun c y l i n d r i c a l s e c t i o n , the f i r s t s t a g e motor. c a s e is g i r t h welded t o an e l - l i p t i c a l f o r w a r d d o m e and a c o n i c a l aft d o m e . T h e e n t i r e c a s e i s m a d e of DGAC high s t r e n g t h s t e e l , T h e f o r w a r d d o m e h a s an opening i n the c e n t e r f o r the pyrogen unit and the aft d o m e c o n t a i n s p r o v i s i o n s f o r attaching the nozzle t o the m o t o r . il f o r w a r d a d a p t - e r is riveted to the c a s e to provide f o r i n t e r s t a g e connectiotl. T h e P B A A propellant i s c a s t i n t o the m o t o r c a s e , then c u r e d , and the nozzle a t t a c h e d .E x c e p t f o r l e n g t h the second s t a g e m o t o r a s s e m b l y i s s i m i l a r to the f i r s t s t a g e . S h o r t e r than the f i r s t s t a g e m o t o r a s s e m b l y , the second s t a g e c a s e a l s o h a s a c a s e venting s y s t e m and i m p u l s e c o n t r o l s y s t e m ( F i g u r e 2-5).
An i m p u l s e c o n t r o l s y s t e m is provided t o reduce f o r w a r d t h r u s t of the second s t a g e m o t o r , a t any p r e d e t e r m i n e d t i m e o v e r the designed operatirlg r a n g e of the s y s t e m , t o p e r m i t effective w a r h e a d s e c t i o n separa"con. The s y s t e m c o n s i s t s of t h r e e p a r t s placed s y m e t r i c a l l y , 120 d e g r e e s a p a r t i n the m o t o r f o r w a r d d o m e . An irnpulse c o n t r o l tube p r o j e c t s f r o m e a c h port at an angle of 3 i i . 5 d e g r e e s f r o m the m o t o r longitudinal c e n t e r - l i n e t o an opening in the m o t o r f o r w a r d a d a p t e r . E a c h port i s plugged with an a l u m i n u m
T h e case venting system e retainer assern
mounted on the external hor
ucing flow interference etween the war
Vent m 121 SECTION 6-C Air Air Vane ane 3 ir Vane
During b u r n i n g , t h e m o t o r c a s e i n t e r i o r i s p r o t e c t e d by a combination of the unburned p r o p e l l a n t , a l a y e r of l i n e r , s w e p t - i n - i n s u l a t i o n i n t h e f o r w a r d d o m e i n s u l a t i o n is a c a r - boxyl t e r m i n a t e d PBAA ( C T P B ) p o l y m e r c o m p o s i t i o n which i s swept into the f o r w a r d d o m e . T h e aft d o m e i n s u l a t i o n , a h a r d , p r e m o l d e d p l a s t i c , s e a l e d with an epoxy and polysulfide c o m p o s i t i o n , i s bonded t o t h e aft d o m e of the m o t o r with the s a m e m a t e r i a l used f o r the f o r w a r d i n s u l a t i o n .
P e r s h i n g m o t o r s a r e ignited by a pyrogen unit which, i n t u r n , i s ignited by two e x - ploding b r i d g e w i r e i n i t i a t o r s and a s m a l l p y r o t e c h n i c c h a r g e . T h e pyrogen unit i s a m i n i a t u r e r o c k e t m o t o r which v e n t s i t s r o c k e t e x h a u s t p r o d u c t s i n t o the c o m b u s t i o n c h a m b e r of the m o t o r t o b r i n g the t e m p e r a t u r e and p r e s s u r e up to the point w h e r e t h e p r o p e l l a n t g r a i n w i l l ignite. T h e g r a i n of the pyrogen unit is a l s o PBAA c a s t and shaped t o e x p o s e as m u c h burning s u r f a c e a s p o s s i b l e . T h i s , i n t u r n , p r o v i d e s a v e r y s h o r t burning t i m e f o r achieving t h e h i g h e s t p o s s i b l e p r e s s u r e and t e m p e r a t u r e i n the f i r s t s t a g e m o t o r c o m b u s t i o n c h a m b e r t o e n s u r e i n s t a n t a n e o u s ignition, T h e pyrogen unit c a s e is f i l a m e n t wound f i b e r g l a s s a t t a c h e d t o a s t e e l a d a p t e r t o p e r m i t a t t a c h m e n t t o t h e m a i n m o t o r c a s e , E a c h pyrogen unit is f i t t e d with two i n i t i a t o r s , e a c h on a s e p a r a t e c h a n n e l t o e n s u r e ignition.
T h e f i r s t s t a g e flight n o z z l e h a s an a v e r a g e expansion r a t i o of 7.06; the second s t a g e r a t i o is 15.06. T h e s e n o z z l e s c o n s i s t of i n t e r l o c k e d s t e e l a t t a c h m e n t r i n g s , a n e n t r a n c e and e x i t s e c t i o n of molded chopped g r a p h i c cloth, a c a r b o n t h r o a t i n s e r t , and a f i b e r - g l a s s s h e l l . T h e s h e l l is a combination of r e s i n - i m p r e g n a t e d , b i d i r e c t i o n a l g l a s s cloth
and a l t e r n a t e l a y e r s of r e s i n - i m p r e g n a t e d , c i r c u m f e r e n t i a l f i b e r g l a s s winding, attached t o the aft end of the m o t o r c a s e with b o l t s through the s t e e l a t t a c h m e n t ring.
T h e guidance and c o n t r o l s e c t i o n ( F i g u r e 2 - 6 ) c o n t a i n s the e l e c t r i c a l and e l e c t r o n i c a s s e m b l i e s t h a t c o n t r o l the t r a j e c t o r y of the m i s s i l e . T h e m a j o r a s s e m b l i e s of the guidance and c o n t r o l s e c t i o n a r e t h e ST-120 s t a b i l i z e d p l a t f o r m and i t s a s s o c i a t e d s e r v o - a m p l i f i e r , the guidance and c o n t r o l c o m p u t e r ( G & C C ) , m a i n d i s t r i b u t o r , and power sup-
p l i e s . T h e p r i m a r y power s u p p l i e s c o n s i s t of the m i s s i l e b a t t e r i e s and a s t a t i c i n v e r t e r . O t h e r c o m p o n e n t s a r e an a i r bottle, a h i g h - p r e s s u r e a i r d i s t r i b u t i o n s y s t e m , and s a f e t y r e l a y s f o r discontinuing a f i r i n g s e q u e n c e , if n e c e s s a r y , a f t e r ground power h a s been r e m o v e d . T h e guidance s y s t e m d e t e c t s e r r o r s i n the m i s s i l e t r a j e c t o r y , a s c o m p a r e d to the p r e d e t e r m i n e d flight path, and c o n v e r t s t h e s e e r r o r s i n t o guidance s i g n a l s . T h e c o n t r o l s y s t e m c o m b i n e s the guidance s i g n a l s with attitude s i g n a l s t o g e n e r a t e a c o r - r e c t i v e s i g n a l f o r t r a n s m i s s i o n to the c o n t r o l packages. ?In the guidance s y s t e m , the ST-120 p r o v i d e s m i s s i l e attitude and v e l o c i t y i n f o r m a t i o n f r o m which deviations f r o m t h e progra-mmed t r a j e c t o r y a r e computed by the C;&CC, T h e s e r v o a m p l i f i e r w o r k s with
t o c r e a t e a s t a b l e r e f e r e n c e f r o m which the t r a j e c t o r y d e v i a t i o n s a r e o b - tained. T h e G&CC c o m b i n e s the guidance s i g n a l s with the m i s s i l e attitude r e f e r e n c e d a t a f r o m the ST-120 to c r e a t e the combined c o n t r o l s i g n a l that o p e r a t e s the c o n t r o l p a c k a g e s . T h e guidance s y s t e m continuously m o n i t o r s the a c t u a l v e l o c i t y and d i s p l a c e - m e n t of the m i s s i l e along t h e t r a j e c t o r y , c o m p a r e s the a c t u a l d a t a with the p r e s e t i n - f o r m a t i o n , and c a l c u l a t e s the e x a c t i n s t a n t f o r second s t a g e cutoff and w a r h e a d s e p a r a - tion.
WINDOW
e a
T h e improved PZa guidance and c o n t r o l s y s t e m i s designed t o function in an a l m o s t i d e n t i c a l fashiori a s i t s p r e d e c e s s o r . The irn Zernentation of both the guidance s c h e m e
and the c o n t r o l s c h e m e w e r e a s e d on i d e n t i c a l c a r r y o v e r r e q u i r e m e n t s f r o log m i s s i l e , The guidance s c h e m e is an implicit scheme which is based on
b e r of computer flown t r a ~ e c t o r i e s t o a r r i v e a t t h e p r e s e t s f o r a given m i s s i o n . The s t e e r i n g s c h e m e i s o timized so that two b a s i c pitcho a s a function of
l t a r g e t s o v e r the P e r s h i n g The control. s y s t e m type of s y s t e m using m i c r o koffs f r o m the ST-12 eh, yaw, and r o i l command e c o m m a n d s which cirive s u c h a fashion to f o r m s i m u l t a n e o u s guidance and c o n t r o l i n all t h r e e g r a m of the guida and c o n t r o l s y s t e m is shown in F i g u r e 2 - 7 . B a s i c a l l y ,
r o v i d e s t h r e e velocity and t h r e e attitude s i g n a l s to the G&CC f o r guidance
and c o n t r o l computations, r e ectively. The C & C t e s the n e c e s s a r y ane commands and i n i t i a t e s
NOTE SL = CR = RN = PO = SECOND STAGE LIFT AND CUTOFF TO WARHEAD
T h e P e r s h i n g g u i d a n c e s c h e m e c o n s t r a i n s the t o t a l t i m e of flight s u c h t h a t the t a r g e t position a t i m p a c t and the f i r i n g a z i m u t h c a n be c o m p u t e d . T h i s r e d u c e s the guidance p r o b l e m t o a p l a n a r p r o b l e m of r e a c h i n g the r e q u i r e d cutoff conditions a s defined i n the g u i d a n c e p l a n e , T h e g u i d a n c e c o o r d i n a t e s and g u i d a n c e e r r o l - s a r e i l l u s t r a t e d i n F i g u r e 2-8. T h e c r o s s r a n g e c o o r d i n a t e , by definition, l i e s p e r p e n d i c u l a r t o the g u i d a n c e plane defined by the s l a n t a l t i t u d e and s l a n t r a n g e c o o r d i n a t e s . T h e s t e e r i n g s c h e m e a l w a y s d r i v e s the c r o s s r a n g e v e l o c i t y and position e r r o r s t o z e r o . T h e s l a n t r a n g e c o o r d i n a t e
is not used f o r s t e e r i n g but f o r computing a p r e c i s e cutoff t i m e b a s e d on the p r e s e t s i.e., s t o r e d v e l o c i t y a s i l l u s t r a t e d i n F i g u r e 2-8) f o r a given t a r g e t . T h e s l a n t a l t i t u d e c o o r d i n a t e i s used f o r pitching o v e r the m i s s i l e s o t h a t i t s v e l o c i t y and position h i s t o r y and f i n a l v a l u e s a r e a s near- a s p o s s i b l e t o the n o m i n a l t r a j e c t o r y preflown i n d e r i v i n g t h e p r e s e t s .
P e r s h i n g e m p l o y s air- and j e t v a n e s , a c t u a t e d by h y d r a u l i c a c t u a t o r s , f o r c o n t r o l . M i s s i l e a t t i t u d e e r r o r s a r e s e n s e d by t h e ST-120; g u i d a n c e path e r r o r s a r e d e r i v e d in t h e G & C C , T h e s e e r r o r s i g n a l s a r e o p e r a t e d on by c o m p e n s a t i o n f i l t e r s in t h e G & C C and r e s o l v e d i n t o i n d i v i d u a l v a n e c o m m a n d s .
M I S S I L E GUIDANCE ERRORS
TRAJECTORY DOWN RANGE
SLANT ALTITUDE ERROR
SLANT RANGE ERROR
/
CUTOFF POINT, EPIPSURED OFF POINT, MEASURED
VELOCITY = STORED OCITY > THAN STORED
POINT, MEASURED VELOCITY < THAN STORED
SLANT RANGE COORDINATE
M i s s i l e r o t a t i o n s i n r o l l and yaw a r e sensed a s e r r o r s r e l a t i v e t o the ST-120 r e f e r - ence; i.e., outputs of the r o l l and yaw g i m b a l angle s y n c h r o s a r e used d i r e c t l y a s e r r o r s i g n a l s . T h e pitch attitude e r r o r is computed by subtracting (by m e a n s of a synchro differential) the pitch g i m b a l angle s y n c h r o output f r o m a c a m - g e n e r a t e d pitch attitude p r o g r a m .
Sign conventions r e l a t i v e t o attitude c o n t r o l a r e defined in F i g u r e s 2-9 and 2-10. In F i g u r e 2-9, the s e n s e of the attitude e r r o r s i s defined for r o l l , pitch, and yaw motions. In F i g u r e 2-10, fin r o t a t i o n s and resulting m i s s i l e attitude c o r r e c t i o n , corresponding to a given attitude e r r o r , a r e tabulated.
T h e a x e s of the t h r e e integrating a c c e l e r o m e t e r s mounted on the ST-12
a c c e l e r a t i o n i n c r o s s r a n g e , s l a n t altitude and s l a n t r a n g e a r e defined in F i g u r e 2-11. Velocity outputs of the a c c e l e r o m e t e r s a r e fed into the C & C C . The slant range velocity
input is used to d e t e r m i n e second stage cutoff. T h e c r o s s r a n g e velocity input is used d i r e c t l y a s a guidance path e r r o r since a z e r o value of c r o s s r a n g e velocity i
T h e s l a n t altitude velocity ihput is effectively c o m p a r e d to a s t o r e d p r o g r a m
G&CC) to d e r i v e a s l a n t altitude velocity e r r o r signal.
Attitude control, is accomplished by processing the pitch, yaw, and r o l l attitude e r - r o r s in the G&GC t o generate corresponding vane commands. Guidance is accomplished
a t t i t u d e and g u i d a n c e c o m p o n e n t s of the v a n e c o m m a n d s a r e s u m m e d t o g e n e r a t e e r r o r s i g n a l s f o r the h y d r a u l i c a c t u a t o r s . T h u s , five c o n t r o l loops e x i s t :
I P i t c h attitude
-
2 Yaw attitude-
3 Slant altitude-
4 C r o s s r a n g e-
5 R o l l a t t i t u d e . -YAM ATTITUDE ERROR
TRAJECTORY
COORDINATE
P I T C H ATTITUDE ERROR
,
\
PITCH DOUR ALTITUDE
COORDINATE
PIT
/
TRAJECTORY
ROLL ATTITUDL ERROR
F i n C o r r e c t i o n s 2W = CLOCKWISE CCW = COUNTER-CLOCKNISI PITCH SLANT
I
ALTITUDEThe f i r s t four of t h e s e loops a r e block d i a g r a m m e d in F i g u r e 2-12, F o r yaw attitude and c r o s s r a n g e control, the p r o g r a m m e d inputs a r e s e t to z e r o . T h e atti-
demodulated and analog filtered p r i sampled at 122 s a m p l e s - ps) r a t e . T h e sampled a t t i t ~ d e e r r o r s i g n a l is compensated by a d i g i t a l f i l t e r . T h i s f i l t e r i s depicted a s ( -F.als)D(Z) i n the block d i a g r a m to e
proportional-plus-derivative t e r i n h e r e n t in the digital f i l t e r , T h e
"
ATTITUDE
T h e accelerometer outputs are demodulated atid analog filtered prior to being sampled
at 30.5 sps. The guidance error signal,
<,
is in general digitally compensated by pr-o-portional-plus-intepl control. This oper,ation is depicted in the guidance compensation
block as eg -?- ei,'~,
T h e roll attitude ioop is block diagrammed in Figare 2 - 1 3 , T h e roll attitude error is
demodulated arid analog filtered prior to beiag sampled ;:I" 122 sps, T h e sampled e r r o r .
signal is c o m p e ~ s a t e d by ti digital filter. of the s a m e f o r m as described above for pitcil,'
y a w cortmi, Guidarice inputs are not required in the roil control ioop.
T h e g e n e r a l i z e d c o n t r o l law which c l o s e s the pitch loop i s :
w h e r e
s
= @P r o g r a m
-
'MissileT h e yaw c o n t r o l law is s i m i l a r except c r o s s range r e p l a c e s s l a n t altitude.
T h e r o l l plane c o n t r o l law is m e r e l y :
Vane d e f l e c t i o n s r e s u l t i n g f r o m the above c o n t r o l l a w s a r e d e s c r i b e d by the following equations:
w h e r e = c o m m a n d v a n e d e f l e c t i o n s i n pitch, yaw r o l l
a = pitch, y a ~ - , r o l l attitude e r r o r c o n t r o l gain
a d a = pitch, yaw, r o l l attitude e r r o r r a t e c o n t r o
113, IY) 11:
e = c o n t r o l g a i n f o r guidance ath e r r o r i n s l a n t
'
aEtitiide and c r o s s r a n g ee = c o n t r o l g a i n f o r r a t e of guidance path e r r o r in s l a n t altitude and c r o s s r a n g e
g y r i
giRf = t t t i t u d e e r r o r i n pitch, yaw, r o l l'PC9 'YC' = attitude e r r o r r a t e i n pitch, yaw, r o l l = s l a n t altitude d i s p l a c e m e n t e r r o r F = s l a n t altitude v e l o c i t y e r r o r E
cf
= c r o s s r a n g e d i s p l a c e m e n t e r r o rcc
= c r o s s r a n g e v e l o c i t y e r r o r i n t e g r a t i o n s t a r t s at second s t a g e ignition,i n the yxv; plane, v m e s 2 and 3 c?efiec! o n e - ! l d f tiie iirnomt. a n d o p p o s i t e t o vane 1 ,
t o p r e v e n t a r o l l m o m e n t . Since v a n e s 2 ~ i n d 3 ; w e e a c h d i s p l a c e d by !iO d e g r e e s f r o n i tine yaw a x i s , the t o t a l f o r c e in tiie yaw plane i s the f o r c e of cine \.;me p l u s tile c o s i n e of 60 d e g r e e s t i m e s the f o r c e of two v m e s , o r one and one-half t i m e s t!ie e f f e c - t i v e n e s s of cine v a n e ,
-411 tlzree v a n e s d e f l e c t e q u a l l y for i ~ o l l c o r r , e c t i o n and t h e t o t s ? fo:.ce avail:*ble i s t h r e e t i r n e s the f o x e a v a i l a b l e f r o m o n e v m e . ' r h u s , the v a n e dcfiection equations b e - c o m e : Vane 3 = i:
+ P I >
-
112 /3 Y T h e s t e e r i n g f u n c t i o n i s a c c o m p l i s h e d the ST-120, G R - C C , v a n e s and a c t u a t o r s , and n e c e s s a r y n e t w o r k s i n t e r c o n n e c t i n g tiie s u b s y s t e m s .-
C r o s s r a n g e s t e e r i n g i s i i l n s t r a t e d i n F i g u r , ~ Z - l 3 ( ~ i ) . Tlhe c r o s s - r m g e a c c e l e r o m e t e r . p r o v i d e s v e l o c i t y info:-mation t o tile G & C C . T h i s v e l o c i t y i s s a m -pled f r e q u e n t l y by the GR-CC a n a l o g - t o - d i g i t a l ( A / D ) c o n v e r t e r t o d e t e r m i n e the amount of c r o s s r a n g e v e l o c i t y e r r o r . By i n t e g r a t i n g t h i s inpu; the position e r r o r i s a l s o c a l - c u l a t e d . P r o p e t . g a i n s a r e applied to the v e l o c i t y and position e r r o r s to f o r m a yaw c o m -
mand, T h i s command is summed with the yaw attitude compensation output and r e s o l v e d into p r o p e r vane commands before b utputted by the
G&CC.
The outputting is accomplished through the digital-to-analog c o n v e r t e r , with the resulting d c voltage applied to the vane a c t u a t o r s . T h e vane deflections r e d i r e c t the m i s s i l e ' s flight path to null out these e r r o r s .-
The s l a n t altitude s t e e r i n g is implemented in a s i m i l a r fashion to tsated i n F i g u r e 2-13(b). The slant altitude a c c e l e r o m e t e r is Sam-A I D c o n v e r t e r to obtain slant altitude velocit T h e s l a n t altitude r e d to a s l a n t altitude velocity p r o g r a m value ontinuously computed a s a function of t i m e in the
C&CC)
to obtain the s l a n t altitude v ocity e r r o r . In the s a m e fashion a s c r o s s r a n g e , the velocity and position e r r o r s a r e weighted and summed to f o r m a pitch command. (The position input, however, is n e i t h e r used n o r integrated until the second s t a g e of flight,) T h i s pitch command&A)
is then summed with the pitch attitude compensation output and resolved into p r o p e r vane commands before being outputted by theG&CC,
T h e s e outputs, through the D / A c o n v e r t e r , a r e applied to the vane a c t u a t o r s , T h e vane deflections r e d i r e c t the m i s s i l e flight path t o null out t h e s e e r r o r s .T h e completion of the P e r s h i n g guidance function o c c u r s when the cutoff command i s i s s u e d and the warhead section s e p a r a t e s f r o m the second stage beginning i t s f r e e flight b a l l i s t i c path to the t a r g e t . T h e cutoff solution i s calculated exclusively f r o m the s l a n t r a n g e a c c e l e r o m e t e r output and the p r e s e t s s t o r e d prior- to flight. The following cutoff equation is solved by the C & C C :
S R V SRV) T
+
P
w h e r e = the cutoff p a r a m e t e r
SRVp = the s l a n t range velocity p r e s e t negative value)
= the slaiit r a g e displacement p r e s e t
T = the weighting factor applied to the velocity e r r o r
ant r a n g e a c c e l e r o m e t e r provided velocity
SRD
= s l a n t range displacement ( i n t e g r a t e d f r o m SRVf =T h e cutoff p a r a m e t e r ) a t liftoff i s a l a r g e fiegative value and r e a c h e s z e r o well into second s t a g e flight a t which t i m e the cutoff command i s i s s u e d . As
A
n e a r s z e r o : thed e t e r m i n e s the p r e c i s e instant of cutoff by using a East, i t e r a t i v e countdown routine.
i n e r t i a l r e f e r e n c e system W i g c r e 2 - 151, consisting of a s t a b l e platform and a n a s s o c i a t e l i f i e r a s s e m b l y , p r o v i d e s a n e a r t h fixed e o o r d i n a t ~ r e f e r -
y s t e m defined by the local horizontal 'rnuth at the launch s i t e . At t h i s orientation becomes s p a c e fixed
Roll Axis of Missile
,
, , X Axis of ST-i20 Roll Axis X ' S Yaw Axis - 1 ~ 0 o i bjvlissiieX Axis Yaw Axis
l
Y Axis !
of Missile
Target
s s i l e d i s t u r b a n c e s a r e s e n s e d t h r o u g h tin '
igidly connected t o the m i s s i l e s a1 a r r a n g e m e n t supporting " r e s t a b i l i z e d
t i o n s of the m i s s i l e : T h r e e A B - 5 s t a b i l i z i n g g y r o s aPar t o e a c h o t h e r on t h
f i e r s and m o t o r s hold the platforrri s p a c e fixed d u r i n g flight,
FiXED TO
MISSILE W L L H A I N SUAFT
R O L L BEARING
STABILIZED CARRIER RIN
MISSILE H U L L
SLANT ALTITUDE ACCELEROMETE
sile is pitched over into the desired attitude for second s b g e motor cutoff, C O N T R O L COMPUTER OUIPU' OF R C L L _
EIET%kT
DEGREE f 5 2 " 4 FREEDOM 0 2 2 9 I 90.1 MICRCSYN ATW i L POSITION -0 C l R R i E R RING W W L C FROM
~s~'To"[ m- INDUCED iST-120
!
FIXED)j
I
PITCH SiGNAL TO CONTROL j ; FIXEC) CCMPGTERAE-3
accelerometers mounted on the carrier ring so that each accelerometer is sensitivetion along a specific direction. Acceleration is sensed in the direction illustrated in
Figure 2-19. The cross range, slaqt range, and slant altitude acee erometers are of
the integrating gyro type. The output of each m i t is a recessional rate proportional-
to-input acceleration with the total displacement angle being the integral of the tot-" a1 iic-
leveling errors about the X - a x i
a d direction of leveling e r
test station. T h e arnplifieG
gyro torquer, causing the s EXCITATION
VOLTAGE
T h e azimuth pic off is a high-sensitivity bridge-type microsyn used only in the ground alignment s c h e e pickoff provides information n e c e s s a r y to align the m i s - s i l e and platform i n azi F i g u r e 2 - 2 6 ) . A p o r r o p r i s m is mounted on the c a r r i e r ring f o r d e t e r m i n i n g pl azimuth heading. It i s oriented s o that a reflected i m a g e (theodolite light s o u r e t e s perpendicularity to t X r e f e r e n c e axis. The heading of the platform, with r e s p e c t to t r u e north, i s viewed d e g r e e s f r o m this heading, T h e pendulums, azimuth pickoff, and p o r r o p r i s m have no function a f t e r launch.
ST-120 ALIGNMENT
l
i
7
AMPLIFIER IN A N U L L POT AZIMUTH PICKUP AT NULL POSITION 1 IONINPUT ROLL ANGLE CCW ROTATION OF STATOR WITH RESPECT TO ARMATURE VIEWED FROM ABOVE T H E ACTION IN LOOP TAKES PLACE L A N G L E ORDER WIRING DRUM @ @ @ @
00
INPUT ROLL ANGLE COUNTER- CLOCKWISE ROTATION OF MAIN SHAFT ABOUT PLATFORM "Y" AXIS WITH RESPECT TO CARRIER RlNG VIEWED FROM ABOVE THE PLATFORM
-
T h e s e r v o a m l i f i e r a s s e m b l y , used in conjunction f o r m , contains s i x a l i f i e r s : t h r e e A M A B - 3 e l e c t r o n i c c o n t r o l a m p l i f i e r s , and t h r e e A B - 5 e l e c t r o n i c conttwo types of a m p l i f i e r s differ only i n c i r c u i t cornpone
a r e used with the t h r e e a c c e k r o m e t e r s . The a c c e l e r s e n s o r provides the input signal to the a m p l i f i e r with power to the c o n t r o l of the a c c e l e r o m e t e r s e r v o m o t o r provided by tine a m p l i f i e r output,
.! 3 INDICATOR
One A B - 5 amplifier provides power to the c o n t r o l phase winding of the r o l l g i m b a l s e r v o m o t o r , and the o t h e r provides power t o the yaw gimbal s e r v o motor. The inputs t o t h e s e two a m p l i f i e r s r o i l and yaw) a r e the outputs of the pitch r e s o l v e r . Resolver
e s a r e dependent upon the pitch angle of the m i s s i l e and the output of the X r e c e s s i o n s e n s o r s ,
T h e third
AB-5
am l i f i e r r e c e i v e s an i n ut f r o m the Z gyro precession s e n s o r ,P o w e r to the c o n t r o l phase of the g i m b a l s e r v o m o t o r i s provided by the am put.
P o w e r t r a n s f o r m e r s a r e used to rovide the r e q u i r e d excitation voltages f o r the pendulums, g y r o s , a c c e l e r o m e t e r s , s e r v o m o t o r s , and attitude sensing devices.
i t c h c a m p r o g r a m m e r is a modular electromechanical device which p r o d u c e s a v a r i a b l e e l e c t r i c a l r e f e r e n c e f r o m which the i t c h attitude e r - r o r many be m e a s u r e d , T h e c a m profile provides both a long and s h o r t c o a s t
the p r o g r a m selection being dependent on d i r e c t i o n of rotation of the c a m , T h
b a s e f o r the p r o g r a m is supplied by a synchronous m o t o r which d r i v e s the c a m through a g e a r reduction and clutch F i g u r e 2 - 2 8 ) , A r e l a y a s s e m b l y provides the switch- ing function r e d p r e s e t t i n g the pitch p r o g r a m ,
p r o g r a m m e r i s checked t o d e t e r m i n e whether o r not
e c a m is turning i n the o g r a r n , During flight, the
t c h c o n t r o l t r a n s m i t t e r ated by the groove i n the use the m i s s i l e t o a s s u m e the t r a j e c t o r y attitude,
y s y s t e m provides the c l e a n , d r y a i r r e q u i r e d ing controlled flight. T h e a i r s y s t e m , located in the guidance sad c o n t r o l section, c o n s i s t s of a s p h e r i c a l a i r bottle, fi?t
t o r s , and a h e e s e r v e s as a storage a r e a and contains i n c h e s of a i r , 0 pslg, The bottle is charged by a i r f r o
station through the umbilical m a hen the m a s t is disconnected, just before launch, the umbilical cou ve s e a l the missile a i r system,
c t s the installation of the a i r d i s t r i &ion s y s t e m while F i g u r e functional d i a g r a m ,
T h e d i g i t a l guidance and contr.01 c o m p u t e r is a Bendix BDX 8 2 computer- coiltaining a c e n t r a l p r o c e s s o r and m e m o r y , an input loutput
(1'0)
p r o c e s s o r designed l o i n t e r f a c e with the P e r s h i n g m i s s i l e and ground s u p p o r t equipment, and a power supply,T h e c o m p a t e r i n t e r f a c e s w i t h the ST-120 s t a b i l i z e d p l a t f o r m , and c o n t a i n s a l l n e c e s - s a r y functions to p r o p e r l y condition the a c c e l e r o m e t e r output and attitude r e f e r e n c e s i g n a l s r e q u i r e d f o r controlling the m i s s i l e f i r s t and second s t a g e c o n t r o l s i i r f a c e s , I n t e r f a c e s a l s o e x i s t between t!le c o m p u t e r 2nd tile m i s s i l e m2in d i s t r i b u t o r - , telemetr-:)- t r a n s m i t t e r , and p r e l a u n c h ground s u p p o r t e q u i p m e n t . In addition, s p e c i a l i n t e r f a c e p r o v i s i o n s a r e m a d e t o f a c i l i t a t e t e s t i n g and m e m o r y loading at the SC'I'S. A s y s t e m o r g a n i z a t i o n d i a g r a m i s shown in F i g u r e 2 - 3 1 ,
GUIDANCE
- - -
AND CONTROL COMPUTE?C o m p u t e r power is obtained f r o m the m i s s i l e e l e c t r i c a l b u s s y s t e m m d c o n v e r t e d to v o l t a g e s r e q u i r e d by the c e n t r a i p r o c e s s o r , m e m o r y , and 1 / 0 p r o c e s s o r . T h e guidance and c o n t r o l c o m p u t e r a l s o g e n e r a t e s t i m e s e q u e n c e s i g n a l s t o the m i s s i l e f o r s t a g i n g
a n d a cutoff s i g n a l t o t e r m i n a t e second s t a g e m o t o r t h r u s t and c a u s e w a r h e a d s e p a r a t i o n when g u i d a n c e p a r a m e t e r s a r e s a t i s f i e d .
W h e r e p o s s i b l e , d e s i g n c o n s i d e r a t i o n s f o r the d i g i t a l c o m p u t e r use e x i s t i n g m i s s i l e e l e c t r i c a l and m e c h a n i c a l i n t e r f a c e r e q u i r e m e n t s , T h e guidance and c o n t r o l s o f t w a r e and h a r d v ~ a r e use s t a t e of tihe art t e c h n i q u e s t o p r o d u c e a c c e p t a b l e r e l i a b i l i t y a g a i n s t guidance s u b s y s t e m f a i l u r e .
F i g u r e 2-32 is a signal flow d i a g r a m of the guidance and control functions performed by the computer. The functions a r e specified by the r e q u i r e m e n t s f o r a delta-minimum guidance profile.
The a j r b o r n e functions m a y be divided into s i x groups: guidance, stability, control, good guidance, time d i s c r e t e generation, and telemetry. The computer accepts bus 2 8
Vdc and 115V, 400 Hz power, and converts the power to usable voltages for the c e n t r a l p r o c e s s o r ,
110,
m e m o r y , and s e n s o r excitations. The detailed design of the functions is discussed below.Hardware and software a r e defined such that optimum a c c u r a c i e s and timing effi- ciency a r e achieved. Reliability of the guidance and control function is optimized by software techniques, such a s redundant calculation and self-test f e a t u r e s . Scaling to optimize word a c c u r a c i e s and an extended length algorithm a r e used t o i n c r e a s e a c - c u r a c y in the cutoff solution.
AID
and D / A conversions a r e multiplexed to and f r o m a common ladder network, and 1/O analog signal processing is designed t o optimize use of the full digital110
word.nee E'unetion
-
The guidance function accepts the m i s s i l e velocity signals inthe f o r m of a c c e l e r o m e t e r synchro voltages and outputs yaw and pitch s t e e r i n g signals t o the control function and a cutoff signal t o the good guidance function. The input sig- n a l s f r o m the a c c e l e r o m e t e r s a r e t h r e e groups of amplitude modulated signals between the s t a t o r t e r m i n a l s of s y n c h r o t r a n s m i t t e r s and r e p r e s e n t instantaneous m i s s i l e velo- c i t y along each of the t h r e e mutually perpendicular axes.
The guidance function converts the sampled input signals to d c signals propor- tional to the s i n e and cosine of c r o s s r a n g e velocity, slant range velocity, and slant altitude velocity. T h e s e dc signals a r e used a s excitations f o r the A / D converter. The A / D converter in turn u s e s a s u c c e s s i v e approximation technique f o r determining digital w o r d s proportional t o the s i n e and cosine of the scaled velocity signals.
The c r o s s r a n g e guidance function i n t e g r a t e s the c r o s s r a n g e velocity to obtain a c r o s s r a n g e displacement signal, and s c a l e s and s u m s the velocity and displacement signals t o f o r m a c r o s s r a n g e s t e e r i n g command f o r the control function.
The slant altitude guidance function s u b t r a c t s f r o m the slant altitude velocity s i g - n a l a d e s i r e d velocity profile f r o m the slant altitude p r o g r a m to f o r m a slant altitude velocity e r r o r signal.
The slant altitude velocity e r r o r s i g n a l is integrated, a s in the c r o s s r a n g e guid- ance function, t o f o r m a s l a n t altitude displacement e r r o r signal, which in t u r n is scaled and summed with the velocity e r r o r to f o r m a slant altitude s t e e r i n g signal f o r the con- t r o l function.
The slant range c o m p a r a t o r guidance function s u b t r a c t s f r o m the slant range velo- c i t y a ground p r e s e t velocity value. The velocity difference s i g n a l is integrated to f o r m a displacement signal which is in turn reduced by a d i s p l a ~ e ~ m e n t p r e s e t value. The r e - sultant displacement difference and velocity difference signals a r e used to solve the cutoff equation, A.
A cutoff d i s c r e t e s i g n a l is i s s u e d by the slant range eorn a r a t o r guidance function when
1
changes sign a f t e r second stage ignition. T h i s cutoff s i g n a l in conjunction with the good guidance determination i s used to t e r m i n a t e second s t a g e t h r u s t and initiatee function are irn
tant errors are small for the cross-
t altitude, due to closed
nt integration, being
idance generator is designated as a f a i l -
ate does riot allow a
ted m l y when the
ocity error less tin
-
2 S l a n t altitude velocity error less t h a n limit;
-
3 Slant range velocity difference within tolerance;
-
4 Slant r m g e dispiaeerneat dif erence within tolerance;
-
5
ST-
-
ut bas not exceeded 1onitor signal present;
-
7 Pressure monitor
signal
present;-
uter has notffai
-
an a predetermined value,
-
iscrete generator function issups rr,rnanri vane unlock, an3 first sta
at p r e s c r i b e d times
signal is issced to the controi function
system currect and eedback s.s;-itching,
i t y function accepts m i s iie attitude signals f r o m
ressed carrier arxplilu.de modulaied
and TOE iriptits are icrosyri outpxs c
is the o u t p u t of a
C X - C T pair, and is the difference betweec actual missile attitu
red pitch program angle, M a x i m u m input voltage for :he y a w
voltage for the pitch ckannel is I T 5 V r m s isat is satura-
eve1 for I ~ O d e s i g n eorisidera"cioils, Sahration of the pitch
input signal does not degrade performance, s computer gains of this magnitude s i g n a l
