S- 0LEVEL--TECHNICAL REPORT TD-77-8

RADIO FREQUENCY SIMULATION SYSTEM (RFSS)

CAPABILITIES SUMMARY

00SAeroballistios Directorate

Advanced Simulation Centeir

•DD

LD Pi .April 1977 MR1' M1?9

1 J •Approved for public release; distribution unlimited

US Army Missile Research and Development CommandRedstone Arsenal, Alabama 35809

i9 03 06 032

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DISCLAIMER

THE FINDINGS IN THIS REPORT ARE NOT TO SE CONMTRUED AS ANOFFICIAL DEPARTMENT OF THE ARMY POSITION UNLESS SO 0E59G-M4ATED Ily OTHER AUTHI"O ZKUM UuI Uiii i--J

TRADE NAMES

USE OP TRADE NAMES OR MANUFACTURERS IN THIS REPORT DOERNOT CONSTITUT6 AN OFFICIAL INDOR&EMENT OR APPROVAL OFTHE USE Or SUCH COMMERCIAL HARDWARE ORt SOFTWARE.

UNCL-ASSIFIEDSECUR

7 ~ITYCLSIFICATION OF THIS PArt M%-., 0.- En~r-~dj

REPORT DOCUMENTATiON PAGE BEFRE AD PINSTIN FORM

a IR 7 12 GOVTACCSSION NO S RECIPIENT*$ CATALOG IjuN8IER

4. TITLEf ren3.hd ,Ij

(a D1O {REQUENCY .hUIATION SYSTEN Ais~) J~lf TechnicaltAAIITIES SUMAR

________________________________________. CONFIRAT of GRANT kUM&EftV.)

William C, (Holt Wayne T. A{iudanDwight A.,,I~1bn-lA E , tchelder]

S. PERFORMIN4G ORGANIZATION DIANE AND ADDR9SS Ia. PRno IL T 0 OjEfCT. TASK(Commander AaI RSt

US Armiy Missile Research and Development Cmad D gAttn: DRDMT -TD /AMCMS 63 303.214131101RedstngArj gUAl. Alabmt 35809______________

It CONTITL.uNG OFFICE NAME AND ADDRESSCoMuaa nerUS Army Missile Research and Development Comman /Apr41 &IAttn: DRX14I-TI AGes

Redstone Arsenal, Alabama 35809 57___1- MSONITORtING A*1tNCY MNAIC & AD $$(I1 diftorfr fro CujmswhIjOffice) IS. SECURITY CLASS. (*I Wej FPM)

/ UNCL.ASSIFIEDOR. DEASSI FICATIONIDOU,.ORADING

'1 SCN EDULE

a [S" OI1TRJITOp STATEMENT

(.1 We. Rqpwtj

ApprovPIed for public release; distribution unlimited.

III. OISTRI~uTioto STATEMENT (.si IA. ~.60ýc 1C.d. I- &J*A ", it 01M, Af. I fte-)

I10. SUPPLEMENTARY NOTES

It KEY WORDS -C..11 aide. .1*1 neK...y odId...tlt by Mock nS

Hardware-in-the-loop simulation Hultiple target traýectory controlElectron~ic countermeasure bimulation polasr za Jon di ers tyRadio frequency environmental modeling Radar target simulationStatistical miss-distance evaluation Engagement scenario 3itvAlationComput~er controlled target generation Radio frequency seeker characterization

a o~ ruAcr rcieete e., m 4 066 N noem IaJIe * hiiry be-A -o--$The Advanced Sirmilatlon Center's Radio Frequenicy Simulation System is

employed in hardware-in-the-loop simulation and evaluation of sensors, guid-ance and control subsystem5 of rada--gkrided missiles in the 4 to 1:-; Ciz fre-

quency spectrum. The Radio Frequency Simulation System facility Is -noperaLing elemnent oi the Advanced Simulation Cernter, Aeroballistic,. Directorate,

ABSTRACT (Continued)

Am L 0 DT~~'NIEIOLT NCLASSIFIED

~ e a SIhTV CLASSIFICATION OF THIS PAIGE (Ob. 0.c. Xe.r.di

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UNI4CASSMUL~E66CUMIT- CLA•.IFICATION OF THIS PAGEMS.. V.a. b-ftv..,

ABSTRACT (Concluded)

US Army Missile Resuarch and Development Command, Redstone Arsenal, Alabama.The facility piovijes a c.-mputer-controlled multiple target array of 534

antennas and an electronic countermeasures ox. 16 autennas (with 4n associatedfetd system and radio frequency gene.'ation system). Two three-axis flighttables and an aerodynamic loader are p'ovided to simulate the dynamic e "rron-ment of a missile in flight. The simulntLion electroumgnetic environmentincludes line-of-sight angles (target positior,), polarized target signatures,electronic countermeasures, clutter, multipath, glint, ond scintillationphenomena. Simulation and testing determinu seeker characteristics such astracking accuracy and engagement parameters such as miss-distance statistics.

Block 19 (Concluded)

Radio frequency missile guidance simulationOpen-loop simulationClosed-loop simulationReal-time critical simulation

UNCLASSIFIEDSeCUI, Y CLASSIF'CATION OF T v1S PAMLraP..* ZMlrd4)

CONTENTS

Page

I• IN T TTODl R OD.-fON .. . .. .. .. . . .. . . . .. .. .. . 5

"II. ENVIRONHENTAL MODELING ......... ................... ... 28

II. TARGET GENERATION ............ ..................... .. 31

IV. CONTROLS AND INTERFACES .......... .................. .. 40

V. SOFTWARE ............................................... .9

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FOREWORD

This documeot provides the potential user of the Radio FrequencySim'jlation System with a summary of the capabilities of the Radio Fre-quency Simulation S;,stem for assessing the facility's suitability tohis specific program and introduces him to the Army's AJvanced SimulationCei.ter. A more detailed discussion of the design and capabilities ofthe Radio Frequency Simulation System is provided in the Radio FrequencySimulatiov System Design Handbook, D243-10004-1, Revision A, 10 March197b. The operational policies of th. Radio Frequency Simulation Systemand a description of how a typical program is implemented by the com-bined Radio Frequency Simulation System and user team are provided inthe Radio Frequency Simulation System User Orientation and OpetationSummary.

The US Army's Advaniced Simulation Center consists of a centiallylocated, modern, hybrid computer complex surrounded peripherally bytree environmental physical effects Ai,nulators. The Inirared, Electro-optical, and Radio Frequeticy Simul3tion Systems are capable of spectralbandwidths and physical motions required for the evalu&tion of a widevariety of guidance systems and components. Under central computercontrol the physical efiects simulators (both opes- and closed-loop)provide real-time simulition capability, thus permitting prec!se aindrepeatable measurements of guidance system performance characteristicsin nonde-trict.'-re tests.

The infra-ed simulation system is a simulation tool for the design,development, and evaluation of infrared sensor systems applicable tosurface-to-air, air-to-air, and air-to-surtace missiles. Sensors inthe 0.2- to 0.4- and 1.0- to 5.0-ý.m bands are hybrid computer controlledin six degrces-uf-fiecdom during the target engagewent sequence. Agimballed fliglht table provides pitch, yaw, and roll movements to thesensor airframe. A target generator simulates a variety of target/back-ground combinations %.hit.h includes tailpipes, plumes, flares, and luse-lages in single or multiple displays against clear, cli-ved, overcast,or 5unlit sky. These are then displayed ii, aziinuth, rievation, range,and aspect by the target projection subsystem through a folded opticalnetwork, a display arm, and a display mirror. Simulation capabilityranges frow open-loop comipuuint ,evaluation to closed-loop total syste-iisimulat ion.

The electrooptLical siciulation systew provides realistic and pre-cisely controlled environments for the nondestruc-ive simulation ofa wide \,arieLy t'f ultraviol'-t, visible, and near infrared sensor systems.Actual sensors are hybrid coniputer controlled in six degrees-of-free:don; while viwing; targets under controlled Illuminatlon levels

3

4 I to 103 foot-candles) in an indoor silmijnt io! chamber, and under

imibient conditions on an ou~tdoor simulation range. Three-dimensionaltarg e t simulation is provided on a 32- X 32-It terraiti/tLrget modelltrans-porter w',Iich features a variet) of topographical and man-made compzle•xc&. b00:l and 300:1 scales, iowiivable model sections, and fixed andMoving t.argeta at any desirable scale. A moving projection subsystemprovides two-dimensional representation. A gimballed flight table capqbl.col simulating pitch. yaw, and roll movements to the sensor airframeis attached to a transport which moves vertically and lateraIlly. Theterrain/target model or the two-dimensional projection subsystem is movedtoward the flight table to provide the sixth degree-of-freedom. Anadjacent high resolution TV/joystick console and proposed helicoptercrew station provide a meanb of evaluating man-in-the-loop guidance andtarget acquisition concepts.

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I. INTHODUCTION

Tile Advanced Simulation Center's (ASC) Radit F1 Uqutllcy il'lulit foil

';ys:tem (RFSS) Is designed to enhance missile syjtewl researtli, dev, lopmcnt,and engineering capabilities through cost-effective simulation of highpcriormance missiles in realistic engagemeots. Realistic engag-e-ntscenarios include tile use of janmiting signals generated by actual Jammersin' the loop, multiple targets, and tic simulation of cluttl, muvi ll,,th,glint, and scintillatioru phenomena. Additionally, missile-target tra-jectoric.; which exceed the performance of today's aircraft can be readilysimulated. The primary application is I ardwere-in-the loop (ItWIL)simulatinu oi passive, seminactive, active, command, beam rider, andtrack-via-missile (TVN) radar terminal-guidance systems for surface-to-air, air-to-air, air-to-fjurface, and surface-to-surface engagenients.The ASC is particularly cost-eifective in test series involving laageparametriC variations wAlere a laige number of runs is required in acontrolled environment. One program, for example, has accomtplistied3000 flight engagements of realistic deceptive janmmer evaluationagainst r sciractivc seeker in three weeks of testing.

An equa~ly important application of the ASC is to bridse the gapbetween analytical missile simulations and flight test programs. Afterpartitioning of thl missile elements aqi a vimulation program, the ASC

can be used to evaluate and validate any combination of the analyticallypartitionted eleinvikLb w tlh,r• . !,;,, |-.•-dv .r ... . •,a.crnnris, -statistical

data can be obtained atnd analyzed rapidly to verity the analyticalmodels and to collect data to aigment or optimize flight test probrams.

Simulation in tile RFSS is accomplished by radiating at operatin8wavelengths to actual seeker hardware functionit,, in a dynamicallysimulated missile-target engagement. Four independent targets can begenerated fnd displayed simultaneously in the 4- to 12-GIlt. range andtwo targets in the 12- to 18-Cliz range. The targets, controllable intarget signature, range, and angular motion, are nrovided by a computer-controlled RF generation system and a 534-element array o1 antennas.Target signature control includes Doppler, range delay, polatizationdiversiey, pulse duration, chirp, etc. Two additional denial electroniccounterixeaturv s (E(N)channels feed 16 ECM array antennas distributedamong the target antennas to display two EQ4 signals !n the rangescited previously for simulating stand-off Janmmers (SOJ) that are slowmoving with respect, to the engagement geometry. ECM signals, generatedby actual jaminets or by the RF generation channels, can be dynamicallycolocated on the target signal through the use of a separate targetchannel to simulate an on-board self-screening or deceptive jenaner.In this sense, the two RF generation EC4 channels cai also b- used tosimulate broadband, on-board Jammers in a self-screening mode. Ejectableand escort screening Jammers (ESJ) can be simulated in a sitnilar mannerwith separate dynamic trajectory control.

II

The i as J.IV-L La Iget t. Inject Lit'% iii accoluil I isitcd tliiuuFh n Cullibiin~t innIIof tnt-uge t inol ioit provid.ed by the ancicuns; alley And autop ilot Mid guttdlatice'-sainsol snot~i~ie pro4_vided by tile two three-axi s rot t tonatl fl.ight s ,11uuu aOWiAerodynamic loads ale simulated using oil actodytnanitc loader actilng onithe missile clev-nis. An artist's concept of the RVSS facility and ntactLical air-defense scenario 1.110L can be simulated Iin the facility INshowo in Figut e 1. Tile location 01 tile RFSS Within Elie Hcliortow Lab-orlatulics aut Oiohwii Iin Ytgtict 2.

The ASC facilitates the following researchi, development, and engi-nearing activities:

a) Analytical and IIWIL simulation support of missile sytitemsthroughout t~heir life cycle.

1) Evaluate breadboard end brasaboard performance.

2) Evaluate basic desuignis and design modifiLent iuns.

3) Establish opt iuniu values for subsystem per[ ,riiijicePntrasneters.

4) Determine missile subsystem pcrloruuance bounds.

5) Optimixe captivye &,-d flight teat programs by pre- and post-flight analysis, .ini'nizc flight teat failurei, and provide eivalUaLioi.for scenarios where fli~.ht programs are not feasible or cosit effertive.

b) RF seeker h~ardwate simvulat ion at microwave frequencies todefine and analyze nonlinear processes Lit sensor hiardware.

c) Performance envelope mapping (miss-distaince statistics)against a multiplicity of scenarios to incro-ose tle leval ofconfidence in fielded missile systemN..

d) Exploitation of acquired and/or fabricated foreign missile

systems.

e) Conduct EC1 and electronic counter counitermeasures (EC04)analyses and vulnerability studies.

I) Explore clutti , mnultipaoth, polarization, glinlt, and scintill-stion effects.

A. ASC General Capabilities and Applications Using the MYSS

Open- or c osed - Inop s imuilIt Ion may be e ondu~ ted w ithvarious missile hardware elemtevts simulated or with various elemients oftile N114L. Closed-loop simulation requires that all elements of Ithemissile system he included, It should be note! that all elements of thiemissile system nced not be present in hardware form because they maybe modeled wathematically in atialog or digital romputers. In open-loopsimulation, the guidance Loop is not. closed. For example, opcni-loop

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simulation is performed with the seeker, guidance electronics, autopilot,or control system independently to characterize and evaluate these ele-ments. HWIL simulation can vary from only one missile hardware elementin the loop (such as the seeker, guidance electronics, autopilot, orcontrol system) to multiple missile elements plus actual jaammers andelements of the ground radar. Open- and closed-loop'simulations can besimple or complex depending on the fidelity required for the modeledelement or phenomenon. The primary applications of the RFSS are staticor dynamic open-loop simulation of missile flight hardwar- or verifica-tion of software models and closed-loop simulations in which the missileguidance hardware is tested dynamically with all other elements of thesystem.

1. Open-Loop Simulation

Open-loop simulation is used primarily to define orverify seeker characteristics such as tracker response, automatic gaincontrol (AGC) characteristics, variable frequency oscillator (VFO) fre-quency, boresight errors, and noise levels. Open-loop testing is alsoused to determine the seeker response to various ECM techniques and tadistributed sources such as clutter and multipath. Autopilot and elevonactuator performance can also be evaluated economically in an open-loopconfiguration. Hardware open-loop simulations provide performance datafor hardware evaluation or information for the development of softwaremodels. The overall simulation capability and efficiency is enhancedby the availability of both verified hardware and proven software models.

2. Closed-Loop Simulations

The dynamic closed-loop guidance simulation maybe an all-software (analytic) simulation or may incorporate one or moreof the flight hardware items shown in Figure 3. Hardware elements ofa ground radar may also be involved. Flight hardware within the totalclosed-loop may be exercised as individual units or in some combinationsuch as an elevon system with the autopilot or autopilot with theguidance sensor.

As depicted in Figure 3, closed-loop guidance simulations can beconducted in the RFSS for all types of radar guidance systems:. passive,semiactive, active, command, beam rider, and TVM. Active and passivesystems involve signal propagation between missile and target. Threesignal paths are involved in semiactive and TVM systems.

For either open-loop evaluation of flight hardware or closed-loopguidance simulation with HWIL, the RF environment for the flight hard-ware is physically simulated in the RFSS. The three categories of thesimulated environment are identified in Figure 4 by the three boxes withthe widened lower edge: aerodynamic moments, angular motions, and tCeelectromagnetic environment.

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The electromagnetic environment is illustraced in Figure 4. Forexample, propagation pat'i effects incluie range delay, space loss, line-of-sight rotation, and other atmospheric anomalies. Target radar signa-tures include glint, scintillation, and Doppler effects.

Figure 5 identifies the RFSS equipment which is used to simulatethe environment for the flight hardware and the type of software requiredto represent othur elements of a missile/target engagement. As shownin the hardware section of Figure 5, a Control System AerodynamicLoader (CSAL) simulates aerodynamic moments on elevon shafts, and twothree-axis rotational flight simulators (TARFS 1 and 2) simulate missilerotational motions for the guidance sensor and autopilot gyros, eachmounted separately on individual t!,bles. The electromagnetic environmentfor the guidance sensor is simulated within a shielded anechoic chamberby means of an RF signal generation system which feeds RF signals tothe target and ECM arrays.

The chamber provides a frec-space environment for the radiation ofAignals from the target and ECM arrays to the guidance sensor. Up tofour simultaneous, independent target signals with continuously control-lable polarization parameters can be radiated from the target array inthe 4- to 12-GHz spectrum and up to two independent target signals inthe 12- to 18-Glzfreluency range. In the 2- to 4-Glz spectrum, fourtargets can be generated and displayed by the addition of power amplifiersin the RF generation subsystem. One or two simultaneous denial EQ4signals can be radiated from the ECM array. Denial ECM signals can beeither vertically, hoyizontniiy, or circularly polarized. Two-dimensicnalmotion of the phase-center of radiation of the target arcay simulatespitch (Y) and yaw (X) target motion. Downrange (Z) motion of the targetis provided by RF amplitude control.

The RF Signal Generation System initiatew signals with thVc time,frequency, phase, and amplitude characteristics required to simulateradar reflections from airborne targets, denial and deception Jammingtechniques, and distributed sources. By means of coaxial-cable and wave-guide paths betwezi,- the RF Signal Generation System and the guidancesensor, simulated reference or uplink signals, and fuzing signals maybe inserted at appropriate points in the guidance sensor. The hardwiredpaths also provide a route for downlink signals.

The software section of Figure 5 depicts in a general manner thesoftware that repre-ents other elements of a missile/target engagement.Block 1 contains the missile mass, motor, and aerodynamic models. The

outputs of Block 1 are missile aerodynamic force and moment coefficients,

mass, center-of-mass location, moments of inertia, motor thiusts, etc. t

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In Block 2 of Figure 5, missile linear and angular accelerationsare computed; these quantities are integrated to determine missilelinear and angular velocities and positions. These computatiias areperformed in the missile coordinate system; therefore, a missile-to-facility coordinate transformation is required to determine positionand angular rate commands for the TARFS.

From Block 2, missile velocities are fed back to Block 1 whereelevon aerodynamic-moments coefficients are computed. Hinge momentsare computed in Block 3 to derive torque commands for the CSAL. Thepositioas of the elevons are fed back from the elevon servos to Block 1.

Missile kinematics from Block 2 and target kinematics from Block4 are used to determine missile/target relative kinematics in Block 5.From repetitive runs of the guidance simulation, end-game statisticsare determined. End-game statistics include miss distance, miss angle,missile angles-of-attack, closing speeds, relative orientation of missileand target, etc. End-game statistics are used in fuzing-, warhead-, andkill-effectiveness studies.

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B, RFSS Physical Characteristics

The rooms and equipment in the RFSS facility are identi-fied in the cut-away and plan views, Figures 6 through 9. In the follow-ing paragraphs, the rooms and equipment within each room are brieflydeLcribed.

1. ECM Rocm

The ECM room is reserved for incorporation of special-purpnse ECM4 equipment into the simulation. The ECM equipment may beused in conjunction with open- or closed-loop guidance simulations orguidance-sensor tests. Signals from the ECM room may be routed bycoaxial cable or waveguide to the target (main) array, the ECM array,or the electronic subsystems of a missile system being exercised in thefacility.

2. Lower RF Room

The low. r RF room contains low-power RF generationmodulation eq,.ipment, and the interface equipment between the mastercomputer located in the control room and the target artay and RF genera-tion equipment. A keyboard printer is also used in conjunction with theinterface equipment which contains six minicomputers.

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Low-power RF signals art used as inputs to high-power RY geteratitonequipment Iocated In the upper RF roo~m, and guidance and fuze electronicsof a guidance sensors mounted on TARFS-l. Five independent low-powerRI signal channels, four target channels, and a reiarence a,-a availablein either C or X bands; two independent low-power RF signal channelsare available at Ku-Band at this time.

3. Upper RF Room

The upper RF room contains the high-power C., X-,ind Ku-band amrlificationi Lquipment, and the DENIAL EW4 generationequipment. Four independent high-power amplification channels areavailable in C-band. Another two amplification channels cor'er X-band.Each of two additional channels cover either X or Ku-band. Each of thetwo DENIAL ECM generators covers the bands 4 to 8 and 8 to 12 CHz.The high-power channels are usually routed to the fuu.r channels of thetarget array; however, they may be routed through either of the two IECM array channels for some unique simulation test requirements. TheI•NLAL ECM signals may be routed to the ECQ array, any channel of thetarget array, or subsystems of a missile system being tested in thelaboratory. ,

4. Array Service. Area

The array service area contains the target artayand ECM array feed system components and control electronics, antenna

mounting fixtures which enable array antennas to be positioned in sixdegrees-of-freedom, and work platforms for service work behind theI array.

5. Microwave Chamber

The shielded anechoic chamber (48- x 48-ft high/wideX 40-ft long) provides a free-space environment. The target and ECMantenna arrays are located on the south wall of the chamber. One primaryaperture and two secondary apertures are located on the north wall. Theprimary aperture is centered on the logitudinal axis of the chamber.TAHFS-1 is located in the primary aperture. The two secoridary apertures arelocated above the primary aperture and provide additional space for open-loopsensor evaluat ions.

The tar'get array consists of 534 antennas located at a fixedradial distanct frnm the intersectioti of the TARFS-1 gimbal axes.The conical field-of-view provided by the target Stray is approximately

420. The target array can transm',t a maximum of four simultaneousindependent signals and can also receive signals from an active guidancesensor.

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Oil tile t*UrgCt ar ray, tile applarent. location (phase cc:ater) oti radia-tion of a target. in controlled by selecting a triad of adjacant antennaswhiich are to radiate and Controlling the relative amplitude and phaseof tile this. radiated signals. Tile amplitudes and phases of tite signalsdetermine the phase-center location within Lthe triad. The target arrayis not & phatied array but a matrix array in that tarkiet positions areCunLrollad throughi phase center motion.

The polarization of signals tratismitted fromi the target stray iscontrollable. Each of Lthe target. array antennas consists of two ortho-gonal linearly polarized elements. Rotatable linear, left- and right.-

F hand circular, or variations of elliptical polarizations are obtainableby thts control of the relative amplitude and phase of the sigiialsradiated by the two orthogonal elements of each antennit. Polarizationand phiase-center location are independently cont~rollable through 6ttenIu-storesland phase ashifters located in thke array feed control rack.

Thle ECMArray consists of 16 antennas distributed among Lthe target arrayantatitas. Each of two independent EC14 signals can be radiated from one of LtheI16 ECKantennas or the two signals may beapplted to dif ferent antennas. Theradiated signal may lie horitontally, vertically, or circularly polarized.

6. Aperture Roonit

Tile aperture roomis provide significant capabilityfer gectieal seeker characterization evaluat ion and related tests wheniciogned-loop Qpieroet~ioisI not requttrcld , KA'ii alrirturo roonin hlrovflle tilecapabiJ ity for int~egrat~ing tI'e seeker with associated mechanical,electrical, and electronic interfaces and thle facility; conductingcertain open-loop testing against. radiating source(%) ; determiningsee~.cr oparational characteristics; and establish~ing required scaling,recording, and data flow parameters. Thle aperture rooms cal be utilizedfor static RF tests or for integrattion and check-out prior to clot-ed-loop simulation in the flight equipment room. Typical aperture room Coll-figuration said interface %vith tile RYSS facility are shiown In Figurc 10.

7. Flighit Equipment. Room (FER)

The FER contains hydroinech.inical equipment. (thle two

TARYS and Lthe CSAL) and electronic intenfaces. The interface equip-

merit. connects or enables connect ions to be made among the flightequipment; the TARFS-l, -2 and CSAL cont~rol -lcctronies; tile inastercomputer; the US Army Missil~e Researchi and Development. Coniniand (MIRADCOM)Hybrid computer complex; RFSS recording equipment; and the P.FSS and Ltheother ASC cells I the electrooptical simulat.ion system (EOSS) and theinfrared simulationi systemi (lRSS)]

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B. Hlydraulic Room

Tile hydraulic rFtom lcontail liour IIydraul iC powerilIpl 1 "Ir . Thl reC Ilowr. t1 IupJI , it's si ve t hh '1 7ARI'S-] , -2, and CSAI.. At,

auxiliary hydraulic power systen (AlIi'S) provides pewes foi missile flighthalidware being eCercisvd in thie FER.

9. Control Room

TI , cont rol roum contaitmi the master conpittcr,compuLer peripherals, the RFSS control, recording and display equipmnont,and tile test c(tnducLor's console. The masteL •omputer ha.; two sp)are1/0 channels to enable connections witl, the ASC hybiid computer cumplux.

C. Simulation Examples (Closed-Loop)

Functional diagrams ol passive, emicicttive, and activcmissile simulationti are showii it Figures 11, 12, and 13. Actual missileh•rdware is used tor the secker antenna, 1imbals, and elecLronics.Special interfaces are fabricated to mace (mechanically, hydraulically,and electronically) the missile hardware to the RFSS facility.

The aimulat ion is started by the tent cotiduct~or at the WeaponSystem and Simulation control panels. The naster .onip1ttor geteratesboth tile target and misaile initc.al trajectories in space coordinates.The master computer then contvcrts these space coordinates to RFSS coordi-nuaLut and iuedb Lite Laurcet- and retIOIC iea 'r-tsjL'al cummiinnd?; to tile maz -

ter/mini interface and the missile coaunands" to the FER interface. Soft-ware models of the mass, motor, and aerodynamics of the missile areImplenmented in the ASC hybrid computers and enable Lhie guidnnce loopto be closed via the direct cell interface with the IR'SS facility.The targets are energized and the missile seeker is enablcd in a launchsequence identical to the real world sicuation.

The target-control and reference-.signalcommuxtands pass through tilemaster/mini interface to six miiiicomputers. M1inis 1 through 4 controltie angular positions of four targets on the array. Mini 6 generatesthe target glint and scintillation update conmmands based upon resident

software target models and current target-missile trajectory itior'mat ioi;it then outputs these conmnands to theoother live minis for imple•uentatiol!in their programs. Mini 5 adds scintillation and Doppler to the situu-lated target and develops RF generation hardware amplitude- and frequency-control signals.

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The RF generation subsystem produces both the target-reflectedand referene, signals. The target signal ir coupled to the main arrayand radiated toward the seeker from controlled angular positions. Thereference signal is tranomitted to the missile electronics via coaxialcable or waveguide. The reference signal simulates the signal receivedby the missile directly from the illuminator.

The missile setker receives the target signals from the main arrayand generates homing guidance signals. These guidance signals arecoupled through the special missiln interface and FER interface intothe master computer. The master computer then generates new targetand missile commands and updates both commands.

Meanwhile,the missile commands from the master computer have gonethrough the FER interface ro the TARFS-l. These signals drive theTARFS-l hydraulic gimbalE to simulate the missile-body angular nmtionsthat occur in actual flight. The proper angular position and rateenviror"ýent are therefore generated by the gimbals of the seeker.

The slawlatior. is a clored-loop guidance simulation operating inreal time with actual missile HWIL. The simulation starts at missileactivation and ends whe2n the missile is at the point-of-clcsest-approach to the target. The simulation tiwing is synchronizedby a master sync and runs at the speed set by the snyc. For simula-tions which involve detailed missile models, the ASC hybrid computercomplex is employed through the direct cell interface with the RFSSSinterface. Truhe interface atluws for the ftight aerodynamics, the auto-pilot, and the missile control surfaces to be modeled using only analogcomputers, hybrid computers, or a digital computer (CDC 6600).

Information recorded on the strip-chart recorders and on digitaland analog magnetic tape includes the same data that are normally tele-metered to the ground in actual missile flight so the ASC data can becompared directly with the actual flight test data. In this manner,the simulation constants can be varied to "match" desired flight testconditions. Inaddition to the normal telemetered data, recordings aremade of various other missile/target flight parameters as required toassess simulation and engagement performance.

Up to four simultaneous independently controllable targets can besimulated; each has unique and independent radar signatures which varywith target roll and aspect angle. The simulated targets may representhelicopters, aircraft, missiles, or surface RF emitters. Target angularand radial motions are jimited by the 3-msec update rate of the arrayand the amount of motion between updates that is acceptable to the user.Target angular position accuracy is nominally 1 mrad with the abilityto provide more accurate angular position if required. Target radialposition accuracy is Range L67. with the ability to command range in0.6% increments. The 3-msec update rate and the accuracies stated

26

~4

previously have provided more than adequate target position and motioncapability for realistic engagement scenarios using the hAWK, StandardAntiradition Missile (ARM), and similar missiles versus aircraft suchas the A-4 and F-4.

D. RFSS Planned Modifications and Expansion

Plans for RFSS capability expansion through 1979 sreas follows:

C&.?ability Availability

Improvement of analog tape recording system 1977

Augmented RF interface to provide RF and targetcontrol from the lower RF room, the FER, andthe aperture rooms. 1977

Additional cabling between RFSS rooms tofacilitate data transfer 1977

Addition of radome boresight positioner. 1977

Target array real-time display. 1977

Two additional targets, two ECK channels, andone reference chaunel in the 12- to 18-GHz range. 197b

TRFI-R1 modified to provide continuous roll with

increased angular velocities and acceleration rates. 1978

Universal weapon system interface (to minimizeinterface requirements for individual programs). 1978

Second Datacraft, increased disc capacity,increased minicomputer memory, and digitalmagnetic tape recorder. 1978

Addition of a seventh minicomputer with its ownteletype for software and minicomputet hardwarecheckout. 1978

Redesign of the master/mini interface to dividethe interface into two drawers with interface tothree minis through each drawer. 1978

Static three-axis seeker positionars for aperturerooms. 1978

Four targets in the 2.0- to 4.0-GHz range. 1979

Improved RF distributed source modeling. 1979

27

, , .. .i - i - i . . . .1 •J

E. ABC Multimode Simulation Capability

The ASC has the capability of multi.,qde seeker simulation,i.e., simulation of missile systems that use RF, electrooptical, orinfrared sensors in some combination for the different phases of themissile guidance during flight. The simulation is accomplished byit-Legrating the three ASC Cells (RFSS, EOSS, and the IRSS) vla the ybrid

computing complex in the proper sequence to simulate the various m-d•ileguidance phases.

II. ENVIRONMENTAL MODELING

A. General

A useful electromagnetic simulation of the real worldrequired that the electromagnetic environment be modeled faithfully.The various target signatures, ECM, clutter, multipath, rain, and chaffmust all be modeled. The degree to which the electromagnetic componentsare modeled depends primarily on the engagement scenario. For example,in simulations such as an EQM scenario where the change in target and0C signature with respect to aspect angle is critical to determiningthe jammer-to-signal (J/S) ratio, extensive look-uptables are requiredbecause both the target signature and the CM emission change as afunction of aspect angle. For other engagements where target signaturevariations- -are n--ot rtc-l sa,--dard-.. .w..e.lg tart, --. l,.- or

even elementary target models might be adequate. Continuous improvementin the ability of the RFSS to provide a high-fidelity electromagneticenvironment is a priority endeavor.

B. Target Signatures and ECH

Swerling target modeling is accomplished on Mini 6, wherethe algorithm determining angular glint is used as an input to the fourtarget minis to determine the target's position on the array; the scin-tillation algorithm output is used to vary the RF generation rangeattenuator output. The more complex, look-up table target models areimplemented in tables on the RFSS master computer. The engagementgeometry is used to determine the target aspect angle. From this, theproper look-up table value is determined; this information is used asa control parameter for the range attenuators. Glint and scintillationmay be added to the baseline table value via either algorithms in Mini 6or other look-up tabLes on the Datacraft.

28

The RFSS ECK capability is extremely diverse. Either denial ordeceptive jamming techniques can be simulated with prerent equipment.Two denial ECM channels are available and can be used either to simulatea standoff jammer whose relative motion in ar engagement is slight, butwhose power capabilities are high, by being fed to one of the 16 *otennason the ECM array or to simulate a broadband on-board noise jammer in aself-screening jammer ukide. Approximately 20 dB more power is obtainedwhen a signal ,gasses thrcugh the EOC array versus the main array. Thepower differential is duts to the simplifJ.ation of the SOI array feedstructure. This difference can be interpreted as a maximum end-gameJ/S ratio of 20 dB. The denial ECM channels have both continuous wave(CW) and pulse capabilities. Specifications for the two denial channelsare sumiarized in Table 1.

Deceptive jamming techniques can be accomplished by proper modula-tion of any target channel. Present RF generation capability includesGaussian and binary noise, lineary frequency modulation (FH), squarewave, swept square wave, sawtooth, and several others. Some of thesetechniques include u e of analog equipment to modulate the channeldirectly while others are implemented by digitally synthesizing the

signal on Mini 6 and using digital-to-analog (D/A) channels to convertthe signal for input to analog jacks in the equipment rack. Up to twotergets, each with an onboard jammer, can be simulated. In certainsimulations, it may be feasible or desirable to use fielded or experi-mental jami.ers as part of the RF equipment. This configuration iseasily accommodated by using the janumer as part o' one of the target

chenn~ ~ J~r ~s1nte-rated in~to thei OF system. With the properinterface and becomes an inzegral contributor to the simulation of theRF environment. One target channel is used to simulate the particulartarget signature and the target channel with the jammer is colocated onthe main array to generate the on-board jamming signal. In a escortscreening snenario, one janmmer and two targets can be simulated.

C. Cluti-ir, Multipath, and Chaff

Advanced distributed source modeling concepts and tech-niques are being studied for HWIL simulation. This study, scheduled forcompletion in December 1977, is considering both hardline injection intothe test specimen and radiation techniques on the main array. The pri-mary conclusions of the study will define advanced methods for distributedsource generation and the necessary hardware and software for implemen-tatton (scheduled for availability in 1979). The study will also definethe environmental spectrums that can be radiated from the main arraywith existing equipment.

29

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Present RFSS capability allows for basic simulation of single- andtwt-tone clutter, Techniques are being developed to radiate a complexclutter signal adequately from the target array. Three channels are

required: one to radiate the sum pattern on-axis and two others toradiate the azimuth and elevation differeuce patterns off-axis. It ispossible, however, that sufficient clutter spectrum fidelity can beobtained by radiating only two signals: the elevation differencapattern and the sum channel pattern. The sum channel patLern is

radiated slightly off-axin in azimuth such that some clutter csignal iscoupled into the difference aximuth channel. Results with thWs method

should not differ significantly from the three-channel clutter approachdue to similarity in spectral characteristics between the differenceazimuth channel and the sum channel.

The simulation of multipath, both specular and diffuse, will beimplemented in much the same way as the clutter simulation, with twosignificant differences:

1) The angle of the multipath signal is different.

2) The power density spectrum is much narrower.

Although a true chaff simulation cannot be accomplished, it ispossible to simulate the effect of chaff on specimen performance byusing the same basic clutLer model and modifying it to yield chaffspectral characteristics.

III. TARGET GENERATION

The control range, resolution, andupdate rate of the RF signalparameters are summarized in Table 1. The array hardware performanceparameters are presented in Table 2. The target generation and arraycapability is summarized in Table 3. The effective radiated power (ERP)of tht array is summarized for representative frequencies and modulationsin Table 4.

The anteaIna array is located on the concave (front) surface of aspherical metal dish which has a radius of curvature of approximately40 ft and a dish diameter of 33 ft. The array provides the capabilityto transmit RF signals, dynamically controlled in relative angular position,or to receive RF signals over a field-of-view of approximately 420 asviewed by a sensor mounted on TARFS-1. The location of the apparent sourceof radiation ofthe RF signals is controllable to within 0.3 mrad, with acurrent working accuracy of at least I mrad.

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ERP at. Array Power Density at Seeker

(dBm) Antenna (dlm/m )

Frequency -

(GHz) Modulation Tnrget Array E(H Array Target Array EM-' Array

5.5 CW 11 26 -22 -7

PULSE 32 47 -1 14

10 CW 9 24 -24 -9

PULSE 36 51 3 18

16 CW -3 12 -31 -21

IuL:!F 15 30 -18 -3

The nominal update ratecf target parameters is 3 msec or 333 llz,Two factors 1imit t,. -,,date rate: the Lime required to run targetmodeling intormation of Mini 6 and the Lime required to run thc fineposition algorithm on Minis 1 through 4. Faster update rates will beavailable in 1978 by adding additional memory to Minis 1 thiough 4 andMini 6 and rewriting the preceding algorithms for optimum execution time.With this modification, update rates ol I kldz will be approached.

A. Target Position and Polarization Accuracy

"Target position" refers to the apparent phase center ofradiation of a signal transmitted by dte target array. Target positionis measured by a sensor mounted on the TARFS-1. "Target position error"is the difference between the target position measured by a sensor andthe coiuanded target position. Target position error varies withinlimits at every point on the array.

"Polarization" refers to the behavior of the electric field vectorof the signal appearing at the sensor. Polarization is discussed in termsof the axial ratio and tilt angle of the polarization ellipse. "Polari-zation error" is the deviation of axial rat io and tilt aug le from theircommanded values. Like target position error, polarization error varieswithin limits at all target positions on the array. The system accuracygoals for target position depend on the frequency and polarization. Inthe 2- to 12-GHz band, the RMS target position error goal at any point,,n the array is that it be less than 0.3 mrad in both the azimuth and

elevation directions for either horizontal or vertical linear polarization.For any other polarization, the goal is 0.5 mrad. In the 12- to 18-GHZband, the RIMS target position error goal at any point on the array is thatit be less than 1.0 mrad for horizontal or vertical polarization andless than 1.5 mrad for any other polarization.

37

IITar-get position and polarization accuracy defined previously are

based on oaeker antenna aperture diameters of 13.5 in. or less for the2- to 12-CHz range and on seeker antenia aperture diameters of 8 in. orless for the 12- to 18-Gifz range.

1. Target PositiLon Accuracy

The actual system accuracy for target positionachieved to date has met the preceding goals in a statistical sense,

although some points on the array fail to mect the criteria by a few

tenths of a milY.iradian on any daily calibration. Target positionerror is a function of the following:

a) Residual near-field effects.

b) Array antenna position errors.

c) Spurious radiation.

d) Phase errors.

e) Amplitude errors.

2. Polarization Control Accuracies

The polarization of an electromagnets waie refersto the behavior of its electric field vector. The most general stateof polarization a wave can take is elliptical, so named because the tipof the electric field vector traces out an ellipse witn time. The twoparameters used to describe the staue of polarization are the tilt angle(¶) and the axial ratio (r). The meaning of these two quantities isdefined in Figure 14. The tilt angle is the angLe whizh the ma;or axis

makes with respect to the horizontal. Tilt angle is restricted to lie

in the range -9 0 0 < r -!- 90 *. The magnitude of the axial ratio is theratio of the major axis to the minor axis and is, therefore, alwaysgreater than unity. The range of r is -- < r : -1; 1 S r < +-. Thesign of r depends on the sense of rotation of the electric fieid vectoras it traces out its ellipse. Positive values of r denote"right-hand"i,.tation, meaning that the fingers of the right hand curl in the directionof rotation of the electric field vector when the thumb points in thedirection of propagation. Negative values of r denote "left-hitnd" rotation.

Polarization states of special interest occut when th? axial ratiotakes extreme values. When the magnitude of r ap)proaches unity, thepolarization ellipse degenerates to a circle. Suh a condcltio-i is called

circular polarization. There are two forms of circular polarization:

right-hand circular with r - +1 and left-hand circular with r = -I.

When the magnitude of r approaches infinity (r -+ ± -), the polarization

ellipse collapses to a litie (the minor axis shrinkr to ;.ero). lit this

case, it is called linear polarization; the electri.c field vector does

not rotate, but is confined to a line.

38

/POLARIZATION ELLIPSE TRACED BYTHE TIP OF THE E VECTOR AS iTROTATES WITH TIME

i--TILTAliGLE-- <T <~-2 2

H MAGNITUDE OF AXIAL RATIO -< fr, -1; 1 < r < +b

1.IF E ROTATES CLOCKWISE WHEN LOOKING IN THE DIRECTIONSGOFr OF PROPAGATIONSIGN OFIFtROTATES COUNTER CLOCKWISE WHEN LOOKING IN THE DIRECTION

OF PROPAGATION

IF THE SIGN OF r IS +, THIS IS CALLED "RIGHT-HAND" SENSE OF ROTATION.BECAUSE IF THE THUMB POINTS IN THE DIRECTION OF PROPAGATION.THEN THE FINGERS OF THE RIGHT HAND CURL IN THE DIRECTION OFROTATION OF THE E VECTOR. IF THE SIGN OF r 13 -, THIS IS LEFT-HAND" SENSE OF ROTATION.

Figure 14. Definition of polarization parameters.

39

It can be shown that any electromagnetic wave is expressible asthe sum of two spatially orthogonal, linearly polarized waves. Therelative amplitude and phase of the two orthogonal linear componentsdetermine the polarization of their resultant. This concept providesthe basic method of polarization control in RFSS, namely, control ofthe relative amplitude and phase of two signals which are radiated bythe two orthogonal, linearly polarized ports of any array antenna.Because the polarization depends on the relative amplitude and phase ofthe two orthogonal, linear components, errors in amplitude and phase.cntrol lead to polarization errors.

The KGSS polarization accuracy design goals are shown in Table 5.These accuracies are typical of those provided by target calibrations.

3. Special RF Target Generation Interfaces

Each simulation program conducted in the RFSS requiressome modification or interface addition to the RF target generationequipment to provide the program peculiar target signals specified bythe RFSS user. This interface can be simple, if user requirements cantbe geneSally met by existing interfaces, or complex, if the requiredtarget signals have not been generated previously by the RFSS. Anexample of an interface in which a jammer signal is generated for coloca-tion on a target signel is shown in Figure 15.

IV. CONTROLS AND INTERFACES

A. Major Control and Interface Equipment

The major RFSS control and interface elements are shownin heavy lines on Figure 16. Items controlled by these elements areshown in dashed lines. Testing in the aperture rooms is, in general,under manual control, but can be patched into the master computer ifrequired.

The primary RFSS control links are listed in Table 6. These linksare discrete or analog and connect areas and equipment as shown. Figure17 shows the layout of the equipment in the RFSS control room. Theprincipal control equipment used by the Simulation Director during testis indicated by bold lines.

B. General Purpose Equipment

In addition to the major control and interface equipment,a supply of portable test equipment is available within the RFSS. Thissupply includes standard RF laboratory equipment such as signal generators.oscillators, spectrum analyzers, network analyzers, time domain reflecto-meters, and portable recorders. A great variety of specialized equipmentis als3 available, with advance notice, from other MIRAICIO laboratories.

40

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C. Interface Equipment

For each simulation program conducted at the RFSS, specialinterface equipment is required. An interface is required for the flighthardware to interface with the RFSS equipment in the FER. This interfaceprovides data and control access to the flight hardware and may be designedand developed entirely by RFSS engineers or may be built around anexisting control panel or test set supplied by the RFSS user. The FERinterface may also be used in the aperture rooms if testing is conductedthere prior to FER testing. A second special interface is required forthe RF generation equipment to assure that the target signals generatedhave the proper signature and characteristics and/or to integrate jam-mingequipment into the RF generation chain. Early identification ofthe requirements for these interfaces as well as the 1/O requirements fortest control, recording, and display parameters are required to implementa successful RFSS program. Additional interface equipment such as missileholding fixtures as well as modification to the RFSS permanent equipmentmay also be required.

Each piece of I,tcrface hardware developed for a specific programgoes through a development and integration effort. Although there isno standard level of effort, as each program tends to be unique, thedevelopment and integration steps are standard;

a) Definition of functional requirements.

b) Developmenumt and review of a design concept.

c) Detail design (drawings and parts lists).

d) Release of rjquests for procurement.

e) Receive, expedite, and inspect parts.

f) Assemble drawer(s)/cable(s).

g) Check out and integrate drawer(s)/cable(s).

h) Integration of the program specific hardware with the RFSS andwith the RFSS and with the software.

D. Computers

Computer control of the RFSS is provided by aDatacraft 6024/1, five Interdata Model 80, and one Interdata Model 85computers. The location and interconnection of these computers are shownin Figure 16. The basic capabilities of these computers are shown inTables 7 and 8. Two fixed-head disc storage units are available with theData craft computer. The capabilities of the discs are shown in Table 9.

i4

g 46

TABLE 7. I&TACRAFT 6024/1 CHARACTERISTICS

Feature Capability

hiemory Size 32,768 Words

Word Size 24, Bits Plus Memory Parity

Registers 5-24 Bit (3 may be used forindexing

Addressing(Direct, Indirectand Indexing) 32,768

Cycle Time 600 neec

I/O CapabilityABC Channels 8 Provided (UP TO 14 Possible)Standard Channel 1 Provided (UP TO 28 Possible)

Priority InterruptsInternal 8 (Standard)External 24

Sense Switches 4

Central Processing Unit(CPU) FeaturesPower Fail Shutdown andRestart ProgramRestrict/Instruction TrapStall AlarmInterval TimerAddress TrapScientific Arithmetic Unit(Floating Point)

Bit ProcessorHardware Bootstrap

Additional computing and data storage capability is provided throughdata links with the ASC CDC 6600 digital computer, the EAI 781 computerand the AD-4 analog computer. Real-time operation with the contrclcomputer complex in the loop is available if required.

E. TARFS and CSAL

The capabilities of the TARFS-l and TARFS-2 end the CSALwhich simulate the flight rotational motions and the aerodyanmic loadenvironment of missile flight hardware during real-time testing areshown in Table 10. The TARFS-1 is used for the seeker; the TARFS-2,with a higher frequency response, is used for the autopilot.

47

T1 SLE 8. BASIC FIRATUiEs u" IlNTERLAA MODELS 80 ANL 85 COMPUTRRS

Feature Capability

Instruction Repertoire 127 Instr. Including Multi-

ply/Divide Both Fixed endFlostingPoint (131 Instr.

for Modal 85)

Instruction Work Format Vull Word (32 Bits) andHalt Word (16 Bits)

Direct Accessing 65.536 Bytes

Data Work Length 8, 16, and 32 Bits

Memory Size 16K Bytes

Accessing Time 332 nsec

General Registers 16 (15 Usable for Index

Registers)

Priority Interrupts 8 (External)

Input/Output Vie' Selector Channel (WlI)(Two Provided) (SeparateTeietype 1/0)

Additional Model 85 Features:

Micro Processor:Micro Instructions 170Control Store Memory (Fixed) 4096 Bytes

60 usec AccessControl Store Memory Dynamic 4096 Bytes

2 00-noeac AccessData Work Length 16 Bits

Universal Clock;Resolution 1, 10, 100, and 1000 psecProgram Control (Intervals) Command, Status,

Count, Interval

F. RFSS Instrumartation

The major elements of RFSS permanent instrumentation anddisplay capability are listed with their location inTable 11. Additionalrecording and display equipment is available through patching to thehybrid compuLer room or by employing portable equipment.

IL

l 48

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i

TABLE 9. FIXED-IEAD DISC SPECIFICATIONS

Feature Specification

Rotational Speed 1800 rpm

Average Access Time 16.7 maec

Transfer Format Serial

Transfer Rate 134,400 wordsisec

Storage 143,360 words

Number of Heads/Track I

Number of Tracks 32

Words Per Sector 112 plus End of Sector word

Sectors Fer Track 40

V. SOFTWARE

Computer control of RFSS checkout and operations is providedby approximately 50 special propose programs. These programs controlall target and test manipulations and provide for automatic data reduction.When requiredby specific tests, auxiliary software programs are developedand/or existing programs are modified by the RFSS software staff. RFSSmnftware in dv4IAPA 4.,tn .4,,tutlg-4.n 4ndmftan#4A.t AnA4 Q4m1*tj,,n ,4nanj,4*,At

programs.

A. Siaulation Independent Software

Simulation independent software includes calibration pro-grams, diagnostics, Tektronix display, and portions of the simulationlogic. Calibration software, for example, provides automated calibrationof both the array and RF generation equipment at the user's designatedfrequency. Diagnostic programs are run on all equipment in a particularsimulation configuration. This software isolates hardware malfunctionsand minimizes the effort to repair the malfunction. Simulation logicthat is considered simulation independent itcludes the Target ControlAlgorithm and RF Generation Control Algorithm. These are Interdatacomputer programs which compute command words to control the array andRF generation equipment per simulation-dependent data supplied by Data-craft computer.

49

ISm •

TABLE 10. TARYS AND CSAL PERFOINANCE SUJHARY

TARFs-i Specifications:

Load limitations:Load size: 16-in. diameter. 60-in. long

Load weight: 150 lb

Performance zharecteristics

Pitch/Yaw Rol1

Angular Displacement ±50 dog ±50 deg

Load Inertia 15 slug-ft2 1.5 slug-ft 2

Position accuracy ±1.0 mrad ±i.0 mradRepeatibility ±0.1 mrad ±0.1 mradVelocity 200 deg/sec 400 deg/sac

2 2Acceleration 900 dog/sec 40,000 dog/secFrequency Response 13 Hz 30 Ht

TARFS-2 Specifications

Load Limitations:Load Size: 10-in, diameter, 10 in. lo•gLoad Weight: 50 lb

Performance Characteristics

Pitch/Yaw Roll

Angular Displacement ±80 dog 150 deg

Load Inertia 0.042 slug-ft2 0.042 slug-ft 2

Position Accuracy ±0.1 mrad ±1.0 mradRepeatability 10.1 mrad ±0.1 mradVelocity 200 deg/sec 700 deg/see

Acceleration 40,000 deg/sec2 200,000 deg/sec 2

Frequency Response 30 Hz 80 Hz

CMAL Specifications

Parameter Characteristics

Load Size (diameter) From 3 to 24 in.Torque Output (maximum) ±1000 ft-lb

Rotational Displacement ±45 dog

Load Inertia 0.02 slug-ft 2

Position Accuracy ±0.05 degTorque Accuracy ± ft-lb

Maxirum Velocity 700 deg/secFrequency Response 50 Hz

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B. Simulation Dependent Software

Simulation dependent software must be developed &pecifi-cally (or modifled) for both open-loop and closed-loop programs. Therecurrently exists a set of open-loop, or seeker characterization, sub-routines. They control both target position and RF generation parameterssuch as power, Doppler, and range delay. Modification of these routinesis usually required to meet the specific requirements of the user'stest plan. Existing closed-loop software includes Executive Control,Missile Model, RF Model, Relative Geometry, and I/0 Handling. Simulationdependent software is required in each of these areas to implement aspecific program. The amount of effort to adapt existing closed-loopsoftware to a user's requirements is a function of the missile character-istics as wall as the user's test plan.

Thu Missile Model, a major simulation dependent effort, may bedeveloped to run internally within the RFSS on the Datacraft computerif not too complex or may be provided externally from the ASC hybrid

computer complex for more complex models. The RF Model, also a majorsimulation dependent effort, includes the target scenario and controlof RF generation equipment. The target trajectory is implemented byinputting acceleration comnmands versus tine. A number of maneuver

tables have been developed, including sine weave and split S. Othermaneuvers are developed as requested by the user. The Relative Geo-metry Model provides tale coordinate transformations and calculationsnecessary to determine the geometric parameters between the MissileModel and the KX' Model. Significant modification of the Relative Geo-metry Model is usually required to implement a specific simulation.I/O handling involves computer control of all hardware in the RFSSfacility. Modification of existing RFSS hardware by the user requiresa corresponding software modification.

C. Software Test Program Support

Test prograsis in the RFSS facility are conducted infive phases as follows:

1) Coordiration and planning.

2) Development.

3) Integration and chetkeut.

4) Test.

5) Documentation.

52

I ---- i -----------

I

Simulation dependent software and support by the software staffare required in the laqt four phases. In the development phase, simula-tion dependent software must be generated to support the user's specificrequirements for missile/target kinematics and RF control. In order toimplement these soctware requirements for a user's program, early identi-fication by the user of his test matrix, I/O; interface; and control,recording, and display requirements are needed. The test matrix providesa list of the tests the user requirer; through a discussion of this matrix,the relative engagement requirements are derived. These are firstexpressed in geometric equations of motion by the RFSS Systems Engineerto establish a relative geometry model as well as a dynamic targetsignature model to define the complete engagement scenario. The soft-ware staff then implements these model in software to provide controlof target/missile relative geometry and RE generation.

The software staff then participates in the hardware/softwarecheckout phase which precedes the actual test. During the test phase,the software staff provides support to assure that the missile/targetmotions and target signatures are controlled as required by the Simu-lation Director.

In the documenLation phase, special software programs are oftenrequired to reduce the large volume of data that can be generated by themulti-run, statistical data complilation. If these data were not reducedautomatically, they would be unmanagable.

D. RFSS Software Programs

The major software programs currently available in theRFSS are as follows:

1) Subsystem Tests.

a) Peripheral Tests.

(1) Datacraft Peripheral Test.

(2) Model 80 Interdata Peripheral Test.

b) Control Console Test.

c) Interface Readiness Test -- Equipment InterfaceReadiness Test.

d) Interface Tests.

(1) Master/Mini Interface Test.

(2) RF Generation Interface Test.

(3) Array Interface Test.

53

e) Array Calibration Unit Test.

f) Strip Chart Recorder Test.

g) TARFS Readiness Test.

h) CSAL Position Test.

i) RF Generation Test.

J) Master Sync Test.

k) Calibration Sensor Test.

2) Calibration and Alignment Programs.

a) Array Alignment Program.

b) Path Loss/Path Length Calibration Program.

c) Path Loss/Path Length Mapping Program.

d) Attenuator/Phase Shifter Calibration Program.

e) Attenuator/Phase Shifter Readiness Test.

3) System Demonstration Programs.

a) Polarization Diversity Test.

b) Target Accuracy Test.

c) Open-Loop Test.

d) Closed-Loop Simulation.

e) Simulation Executive Control Program.

f) ECM Array Control Test.

4) Simulation Aids.

a) Datacraft - Real-Time Graphics Program.

b) interdata.

(I) Target Control Program.

S(2) ECM Control Algorithm.

(3) Polarization Control Algorithim.

(4) Coarse-Positicn Contiol Algorithm.

(5) Fine-Position Control Algorithm.

(6) Pr Generationi Algorithm.

(7) Noise Algorithm (Glint, Scintillation).

54

BII

L 1 '

5) Special Programs.

a) Test Directory Initializor.

b) Test Directory Editor.

c) Fast Fourier Transform.

d) Master/tlini Interface Diagnostics.

e) Tektronic Graphics Diagnostics.

f) Near-Fields Effects Correction Table Program.

g) Low/High Level Modulator Calibration Program.

h) FR 1900 Test.

55

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