the integrated air force missile test center data processing facility-lr3

8/3/2019 The Integrated Air Force Missile Test Center Data Processing Facility-lR3

1/7

PROFESSIONAL GROUP ON RADIO TELEMETRY AND REMOTE CONTROL

EDITORIALThis is th e first issue of the Transactions of the

IRE Professional Group on Radio Telemetry and RemoteControl. Publication will be quarterly. Papers are invitedin the following general field of interest to the group, asdefined in the Constitution and By-Laws:I. Radio Telemetering(a) Systems(b) Components(c) Data Reduction - Information HandlingII. Remote Control(a) Automatic control systems or componentsusing analog computing processes and

analog data transfer methods.(b) Automatic control systems or componentsusing digital computing processes and datatransfer methods.The closing date for consideration of papers for eachissue will be si x weeks prior to th e publication data.

Papers should be submitted to the papers committee:1. Charles H. Doersam, Jr., (Chairman) D40, SperryGyroscope Co., Div. of the Sperry Corporation,Great Neck, N.Y.2 & 3. Frank P. Lehan and A. William NewberryJe t Propulsion Laboratory, - CIT, 4800 OakGrove Drive, Pasadena, Calif.4. James B. Wynn, RCA-AFMTC, Patrick Ai r ForceBase, Cocoa, Florida5. Foster N. Reynolds, Ralph M. Parsons Co.,224 Strawbridge Ave., Melbourne, Florida6 & 7. Bernard S. Benson and J. Rucker; Benson-Lehner, 2340 Sawtelle Blvd., West Los Angeles64, Calif.8. Perry Crawford, Jr., IBM, World HQ, 590 MadisonAve.,New York, N. Y.9. Donald R. Burbeck, Ramo-Wooldridge Corp.,LosAngeles, Calif.10. George R. Barton, Office of Naval Research -SDC, Port Washington, N. Y.

THE INTEGRATED AIR FORCE MISSILE TEST CENTERDATA PROCESSING FACILITYCharles F. WestSoroban EngineeringMelbourne, Florida

Most air vehicle test programs generate require-ments for large and flexible data processing centers. Theplanning of such facilities must include provisions forth e analysis of performance data recorded by instrumenta-tion external to the test vehicles (i.e. optical and radarinstruments) as well as by internal instrumentation(telemetry, etc.).In the past, the efficiency as well as the scope ofoperations which could be undertaken at a data reduc-tion center were often determined by the available com-puting machinery. Because of inadequate computationaldevices, many ranges were forced to consider methodsfor processing flight te st data which did no t " appre ciablydeteriorate the data." Had computers of ample excesscapacity been available. methods for processing test

data would in many instances have been employed toyield slightly improved results, even though the timeinvolved in computation were multiplied several fold.Such considerations ar e especially important at missiletest ranges when one considers the tremendous cost in-volved in testing missiles.For these reasons, the Air Force Missile TestCenter's (AFMTC) data reduction center was predicatedon a sizeable computing machine as an absolute neces-sity (Fig. 1). Since no practical commercial digitalcomputer was available at th e time planning of th efacility commenced, a development program was initiatedwhich ultimately le d to th e development of th e FloridaAutomatic Computer (FLAC). FLAC is presently usedto determine space position and attitude information

1

AlultIXDoM1a1UfIX Ra


2/7

Fig.1-Artist'sconceptionofAFMTCdatareductionfacility.



3/7

PROFESSIONAL GROUP ON RADIO TELEMETRY AND REMOTE CONTROLfrom triangulating fixed camera and cine-theodolitepictures as well as stability and aerolastic effects ofairframnes from raw telemetry data collected on th eFlorida test range. The machine performs such computa-tions as th e determination of a cine-theodolite spaceposition using a two instrument least squares solutionwith corrections for refraction, collimation, earth curva-ture. etc.. in less than four seconds.

and uiardunded, with high or low order results avail-able) division (remainder available) complete decimal-binary and binary-decimal conversion, logical transfer,shift,equality sensing, comparison, file, etc. At pre-sent the machine employs a 512 word mercury delay linememory which is capable and planned for expansion to4000 words. Augmenting th e above, four 250 word persecond magnetic tape units provide 400,000 words of auxi-

Fig. 2 - Artist's conception of(FLAC).To present a more detailed description of the machineit should b e s tat ed that FLAC (Table 1 and Figs. 2, 3,4 ) is a binary, general-purpose, large-scale, self-sequenced, automatic electronic digital computer. The44 binary digit plus sign machine operates with a float-ing three address operation code (i.e. th e specifiedaddresses may be either absolute or relative to eitherth e program counter or a special "B" register). It per-forms additions, subtractions, multiplications, (rounded

liary external memory. The external memory units operatewith permanently recorded block marks for hunting, aswell as facilities for altering any block of data stored onan external memory tape. FLAC's operating speeds andcircuit philosophyresemble th e Bureau of Standards SEAC.However, th e machine employs only 380 tubes (15,000germanium diodes) plus an additional 350 for each 512words of acoustic delay line memory. The design of th ecomputeris based on th e use of seven plug-in assemblies

3



4/7


5/7

PROFESSIONAL GROUP ON RADIO TELEMETRY AND REMOTE CONTROL 5which contain all circuit elements. Built-in refrigeration The following paragraphs will be devoted to brief de -provides for parallel cooling of all components, thus scriptions of data collection devices such as cine-theo-insuring long life and improved machine operation. dolites and their associated data preparation equip-ments.The most common cine-theodolites in use on mis-sile test ranges are German Askania theodolites, orcopies thereof. With these instruments, photographicexposures of a tracked target indicate the displace-ment of the object from the optical axis of the instru-ment. Azimuth and elevation dials which indicate th einstrument's pointing ar e also recorded on this sameexposure. Several machines ar e available for readingAskania theodolite records, one of th e more elegant ofwhich is that pictured in Figure 5. This machine pro-jects th e camera record image onto an opaque screen andautomatically transcribes th e location of manually posi-tioned crosshairs, thus eliminating errors which fre-quently occur during manual reading, transcription, andretranscription of data. Crosshairs ar e provided for mea-

suring th e displacement of th e target from th e opticalaxis as well as for reading vernier scales attached toth e azimuth and elevation dials. When averaged overan eight hour day, such theodolite readers produce 170or more read frames of film pe r hour. Nine hundred ormore frames of useable Askania theodolite data can beexpected from an average successful test flight.Fig. 3 - Photo of FLAC facility.

Therefore with th e availability of such a computer,it became obvious that in order to provide a balanceddata processing facility at the AFMTC, it should benecessary to integrate th e computing system with thefilm reading and data collection devices. The immediateand more apparent requirements indicated that data col-lection and reading devices should, where possible, bedesigned to present data in a form suitable for ready in-troduction into th e computer. Further, recognizing thatmost experimental d at a c ol le ct ed on th e test range con-sists of systematic series of readings, it appeared ob-vious that tape data recording would generally exhibitgreater economies and higher efficiencies than might berealized from other methods such as punched cards, etc.For these reasons, procurement of all film readers (i.e.those required to read Askania theodolite records, Ballis-tic and ribbon-frame camera records, as well as oscillo-graph records) was predicated around devices whichwould prepare punched paper t ap e s ui ta bl e for directintroduction to the digital computer. In addition, elec-tronic digitalizing equipment with associated magnetictape digital recorders have been installed at th e datareduction center to prepare th e outputs of telemetryground stations for introduction into th e computer. Shaftcoders with associated tape punches to operate withradars scattered throughout th e range are also planned.

Fig. 4 - Photo of back of FLAC racks, showing intercon-necting signal leads.To observe accelerations and velocities, particular-ly during launch and impact, high-speed, wide-angle lensfixed cameras ar e employed. Measurements of photo-



6/7

TRANSACTIONS OF THE I.R.E.graphs from such cameras ar e made on optical compara-tors, toolmakers microscopes, etc. Space position andattitude information of observed objects can, as withcine-theodolites, be determined by triangulating th eposition of an object from th e photographic records pro-duced by two fixed cameras. Th e optical comparator ofFigure 6 provides an instrument with a power drivenstage capable of measuring such photographic filmstoa precision of 5 microns over a 6" x 6" area. Magnifica-tions from 6 to 19 power ar e available.

tion system is in operation at th e Air Force MissileTest Center (Fig. 7) . Even though th e system has a digi-ta l output, it makes use of analogue techniques forcalibration and computations where th e precision ofdata being processed does not warrant use of digitalmethods.

Fig. 5 - Photo of telecomputing theodolite reader.

Fig. 7 - Photo of Melpar telemetering data reduction system.

Fig. 6 Photo of Coleman optical comparator.

In addition to the theodolite and accelerationcamera readers, several oscillograph record readers arein service which produce punched tape. A typicalmachine will handle film or oscillograph paper of widthsup to twelve inches and display an image on a 12" x 24"projection screen. Again crosshair positions are auto-matically tabulated by an electrically actuated type-writer as well as punched into paper tape.For analysis of internal performance data as tele-metered from the missile, semi-automatic data reduc-

During normal operations, telemetry data is re -corded throughout the range on Ampex magnetic tape re -corders for subsequent processing at th e centralizeddata reduction facility. The data reduction system thensimultaneously processes telemetry data from si x tele-metering channels (either commutated or continuouschannels) at a rate equivalent to real-time. Th e dataprocessing system accepts its raw data in th e form ofdc voltages from either FM-FM telemetering subcarrierdiscriminators or decommutator gates, as well as frompulse duration modulation (PDM) gates. Such time vary-ing input voltages ar e fe d into masked cathode ray tubearbitary function generators which generate correctingcalibration signals for addition to (or subtraction from)th e input voltages. Variable amplification of the signalas well as provisions for th e addition or subtraction of adc bias are available, thus permitting th e raw datasignal to be scaled, zeroed, and linearized. Outputs ofthe calibrator are available to drive oscillograph galvano-meters, pen recorders, or one of s ix d ig it al coding units.The coders sample calibrated output voltages at con-trollable rates of from two samples per second to fivehundred pe r second with a precision of eight binary di-gits. Th e pulse code for each sample is recorded on a

6



7/7

PROFESSIONAL GROUP ON RADIO TELEMETRY AND REMOTE CONTROLsix channel magnetic tape in a form suitable for in-troduction to FLAC, the AFMTC high-speed digital com-puter. Thus, t im e col lat ed data from up to six endinstruments may be prepared for subsequent digitalcomputation.Computations involving telemetered data generallyconsist of simple ratios or products, or roots or powers.The majority of telemetered data is only desired asscale factor corrected, zero shifted, calibrated curvesand only in a few cases, ar e computations of sufficientcomprexity as to require or justify digital processing.However the large-scale digital computer at the Ai r ForceMissile Test Center is presently being used to processtelemetering data for lateral stability determinationsas well as studies of various aerolastic effects of mis-sile airframes.

Final processed data is tabulated for final p re -sentation on modified form letter writing machines.Automatic digital plotters have been secured for pre-sentation of graphical results.From th e preceding paragraphs, it may be seenthat as soon as possible all test records at large datareduction centers are transcribed into a medium freefrom further contamination by human operations, computa-tions are performed with automatic machinery, andautomatic machinery is employed for presentation of thefinal data.Even in the described facility it is recognizedthatmuchofthemachinery is cumbersome and approachingobsolescence. However it is now apparent that th e con-tinuing attempt to increase the efficiency of data reduc-tion centers is definitely producing results.

BASIC DESIGN OF COMMUTATING DEVICESMartin V. Kiebert, -Jr.Bendix Aviation Corp.Teterboro, N. J.

Discontinuous commutation is an old ar t in theelectrical and communication fields.One type of applica-tion is illustrated by the commutation of dc motors, asecond by rotary commutation of multiplex telegraph cir-cuits. The latter involves a problem similar to that en-countered with telemetering switches. An additional ap -plication is found in the conventional radio sound level.Withregardto most systems previous to telemetering,space, weightand power requirements were of no particularimportance. In th e telemetering field, however, thesefactors ar e all at a premium. Every effort must be madeto select th e optimum system configuration in order topermit the greatest latitude of application.In th e literature and in work carried on under atelemetering development program, several points cometo light as important in the design of any commutator.These points should be carefully considered both fromth e engineering and economic point of view, and are asfollows:1. Dependability and life of th e unit,2. Power required and power available for drivingthecommutating assembly,3. Tolerable maintenance requirements, includingpermitted frequency of maintenance,

4. Current density at th e operating contacts,5. Tolerable noise level,6. Thermal-electric effects,7. Size and weight.In cases of high current density, such as dc motorcommutators, much experience has been gained in th eselection of suitable brush and contact materials. Be-cause of the need for excellent conductivity and the pro-hibitive cost of silver and its alloys, copper is themost common material for contacts. It is interesting tonote that various types of copper have been widelyused. Although casting would appear to be a logicalfabrication technique for this type of application, ex -perience has shown that forgings a re b et te r conductorsand make th e best contacts.Two problems exist in regard to dc motor coppercommutators: relatively rapid c on ta ct w ea r, and th eneed for keeping th e insulating material below th esurface of th e active conductor. A relatively soft brushmaterial is always used, so that it will be eroded morerapidly than the harder-to-replace copper contact. In-terestingly, the first brushes were of fine copperscreen, followed by graphite and carbon which served ina quasi-satisfactory manner. About 1930, some of the

7

the integrated air force missile test center data processing facility-lr3

Documents