APOLLO C-B AWD RADAR TRACKING CAPABILITY

2y ago
17 Views
2 Downloads
639.58 KB
18 Pages
Last View : 1m ago
Last Download : 2m ago
Upload by : Amalia Wilborn
Transcription

,/IX-551-67-503APOLLOC-B AWDRADAR TRACKING CAPABILITY--,i.--,P.I E. SCHMID/,. \\I\P71’1,I\I\L/SEPTEMBER 15, 1967i’\ ‘1//I/

X-551-67-503APOLLO C -BANDRADAR TRACKING CAPABILITYP. E. SchmidSeptember 15, 1967Mission and Systems Analysis BranchMission anU Trajectory AMiySiS DivkioiiGODDARD SPACE FLIGHT CENTERGreenbelt, Maryland

APOLLO C-BANDRADAR TRACKING CAPABILITYP. E. SchmidABSTRACTThe purpose of this report is to document the current (1967)tracking capability of the Apollo land and ship based C-band radarequipment. This documentation is in support of the Apollo Navigation Working Group task of periodically updating the information contained in Technical Report AN- l "Apollo Mission and Navigation System Characteristics", a joint Goddard Space FlightCenter-Manned Spacecraft Center publication.iii

APOLLO C-BAND RADARTRACKING CAPABILITYContentsPage.MSFN Land Based C-Band Radar Characteristics .Apollo Ships C -Band Radar Characteristics .Apollo Spacecraft C -Band Characteristics .Maximum Range Calculations .S u m m a r y . . .1.O Introduction12.013.04.05 .O6.0V25612

ABBREVIATIONS USED IN THIS REPORTC -bandfrequency range of 4 to 8 GHz (all equipment in this reportoperates from 5.4 to 5.9 GHz)CMCommand ModuledBdecibeldBmpower level expressed as decibels relative to 1 milliwattdegdegreeftfeetGHzl o 9 HzGSFCGoddard Space Flight Center (NASA)Hzunit of frequencyIUInstrumentation UnitLMLunar ModulemmetermradmilliradianMHzlo6 Hzmicrosec.- cycles per secondradians)secondsMSCManned Spacecraft Center (NASA)MSFNManned Space Flight Networkn. mi.nautical mileNASANational Aeronautics and Space AdministrationRFradiofrequencyS/Nratio of mean power during the received pulse to mean noisepower.secsecondvi

APOLLO C-BANDRADAR TRACKING CAPABILITY1.O INTRODUCTIONThe purpose of this report is to document the current (1967) tracking capability of the Apollo land and ship based C-band radar equipment. All currentlyplanned Apollo missions require C -band radar beacon (or "transponder") tracking of the Instrumentation Unit (IU). There w i l l also be C-band beacons aboardthe Lunar Module (LM) and Command Module (CM) up through and includingmission 503 (ref. 1).During the Lunar mission (Mission 504 - first lunar landing capability) thefive Apollo ships w i l l employ C-band tracking as follows:1.The Vanguard (T-AGM-19) during launch and insertion into earth orbit.2.The Redstone (T-AGM-20) and Mercury (T-AGM-21) during injectioninto the translunar trajectory.3.The Watertown (T-AGM-6) and Huntsville (T-AGM-7) during spacecraftreentry into the earth's atmosphere. (ref. 2).The parameters used in this report reflect current individual site and shipcharacteristics associated with the various C -band radar types. Also includedin the calculations a r e beacon power levels, antenna gains and radio frequency(RF) losses associated with the LM, CM, and IU.The Manned Space Flight Network (MSFN) is taken to include all stationsconfigured to support the Apollo program. Thus, along with the NASA sites suchas Bermuda (BDA) and Carnarvon, Australia (CRO), a r e included Apollo supportelements of the Eastern Test Range, Western Test Range, White Sands MissileRange, Eglin Gulf Test Range, and the Weapons Research Laboratories atWoomera, Australia. This definition of the MSFN is consistent with such definitive Apollo documentation a s NASA MG-401 (ref. 3).2.0 MSFN LAND BASED C-BAND RADAR CHARACTERISTICSThe MSFN land based C-band pulse radar types consist of the AN/FPS-16,AII/MPS-25, AN/FPQ-6, AN/TPQ-18 and AN/MPS-26. The MPS-25 is a transportable version of the FPS-16, the TPQ-18, a transportable version of theFPQ-6. The indicator AN (originally "Army - Navy"j does mt necessarily1

mean that the Army, Navy or Air Force use the equipment, but simply that thetype nomenclature was assigned according to the military nomenclature system(ref. 4). The meaning of the three letter prefixes; FPS, MPS, FPQ and TPQare:FPS-fixed; radar; detecting and/or range and bearingMPS-ground, mobile; radar; detecting and/or range andbearingFPQ-fixed; radar; special, or combination of purposesTPQ-ground, transportable; radar; special, o rcombination of purposes(for full listing of military nomenclature see ref. 4).The individual site characteristics pertinent to maximum range calculationsa r e given in Table 1 which is based upon current information from RCA, Moorestown, New Jersey (ref. 5).3.0 APOLLO SHIPS C-BAND RADAR CHARACTERISTICSA s indicated in Table 2 , the Apollo ship C-band radar types consist of theRCA AN/FPS-16(V), CAPRI and modified CAPRI. Table 2 presents thosecharacteristics pertinent to maximum range calculation.The FPS-lG(V), used aboard the Apollo insertion and injection ships, i s ashipboard version of the FPS-16. The CAPRI ('Compact All-Purpose RangeInstrument") used aboard the reentry ship, the Watertown, i s a radar which hasevolved from the FPS-16, employing solid state and integrated circuit design.The "modified CAPRI" aboard the reentry ship Huntsville incorporates the following deviations from the standard CAPRI system: (ref. 5 and 6)1.Peak transmitter power 3.2 megawatts.2.Cooled parametric amplifier to achieve a 1.1dB noise figure in thereference (or sum) receiver channel.3.Limited electronic antenna elevation scan by means of transmitterfrequency stepping during acquisition. The electronic elevationsector scan covers 6" while a 23" azimuth sector is scanned mechanically. The 6" by 23" window is scanned in 5 seconds (ref. 6 and 7).2

Table 1Apollo Land Based C -Band Radar CharacteristicsUnambiguousRangeapability(n. mi)CNVCape KennedyPeak Lieceiver ReceiverAntennaNoise?owerBand'RadarDia. Gain?'IegaFigurewidthT m e watts) (ft) (dB)(MHz)(dB)- FPS-1642112 44.5MLAMerritt IslandTPQ-153295141.632000PAFBPatrick A i rForce BaseFPQ-63295141.632000G BIGrand m a m aIslandFPS-16TPQ-1f1312 44.529 5 111421.6100032000SSISan SalvadorIslandFPS-16112 44.51121000GTIGrand 41.632000BDABermudaFPS-16FPQ -61312 44.529 ionLocation1000CY1Grand -1631PREPretoria,South PQ-63295141.632000WOMWoomera,AustraliaFPS-16112 44.5112500HAWKauai, HawaiiFPS-16112 44.542500CALPoint ArguelloCaliforniaFPS-16112 44.542500WHSWhite SandsFPS-16112 44.542200EGLEglin A i rForce BaseFPS-16112 44.5112200104129 5112 44.5' o m i n a ! r c q i i c n c j :raage is 5.4 te 5,? C-HZ for all types2For 1 microsecond pulsewidth3All FPS-16 radars except HAW and CAL are lineariiy poiarized, aii others havepolarization capability3CiicdZi

0,000,hld *000,hlM0@?h!hl0000,M9 9h!hlhlhlhlP;0Gm.r(ka,l-irll-il-irll-iWWWc “ r ’l-iffiwd :WWWhl-irll-ir l r ikcdl-iril-il - i ? -,2uacdlW01ffiac4aiWWil-iI ”&eIuFra%Fs“accdcll040203a9drir/lh0h -,k0El.d -,80a,cdk42.r(0.-a, Elh -,a,a,a,ck.r(l-iSII4kGc,9)k

4.0 APOLLO SPACECRAFT C-BAND CHARACTERISTICSThe C-band beacons (or "transponders") aboard the IU, CM, and LM alloperate in the same manner, that is, an interrogating pulse (or pulse group) isreceived and detected by the beacon receiver to provide a trigger to the beacontransmitter pulse modulator. The beacon characteristics affecting maximumrange calculations are given in Table 3. N o C-band beacons are planned aboardthe C M and LM beyond Mission 503. During hnar Missions the IUwill bejettisoned at an altitude above the earths surface of 6200 n.mi.Table 3Apollo C -Band Beacon C mracteristicsRFLosswatts) (dB)PeakPower31nstrurnentation MotorolaUnit (IU)SST-135C1ACF621 G-1'Lunar Module(LM)MotorolaAN/DPN 6fCommandModule (CM)Note:2fiximumReceiverTransmitAntennaPul se Width -6.561-6500.75-70-60.75-701.No C-band beacons aboard CM and LM beyond Mission 5032.Antennas are circularly polarized3.For Lunar Mission I.U. jettisoned at 6200 n.mi. altitude during the translunar phase.5

5.0 MAXIMUM RANGE CALCULATIONS5.1 BEACON TRACKThe maximum range calculation from each C-band r a d a r location i sstraightforward using the information presented in Tables 1, 2 and 3. The"unambiguous range" has to do only with the particular data processing technique employed and is not a function of radio frequency propagation. Therange limiting link is easily shown to be spacecraft to earth transmission.This is a result of the relatively high peak power radiated by the C-band radartransmitter, f o r example, 3 megawatts for FPQ-6 or 1 megawatt for FPS-16.The maximum range for beacon track in the absence of pulse integrationis given by:where:P, peak radiated beacon power (watts)G, beacon transmit antenna gain radar receive antenna gain wavelength corresponding to beacon frequency (meters)L, beacon total R F losses& radar receiver total R F lossesL, polarization lossS- the ratio of mean power during the received pulse to meannoise power required for a high probability of acquisition Boltzmann's constantNk 1.38 xO L L 1(Joules /OK)B equivalent noise bandwidth of radar receiver (Hz)Te effective radar receiver noise temperature (OK)R maximum range corresponding to the specified signal tonoise ratio.6

The "effective noise temperature" includes the effects of noise interceptedby the antenna, (earth radiation into sidelobes, tropospheric noise, Galacticnoise and so on), the noise generated by the R F coupling between antenna andreceiver (waveguide, diplexers, duplexers) and the receiver noise. This effective temperature is generally expressed as: (see for example ref. 10)where:TL waveguide and/or transmission line temperatureTR receiver temperatureTa effective antenna noise temperatureF1 & a radar receiver R F losses receiver noise figure ratio of actual receiver preamplifierand mixer noise spectral density to the theoretical minimumspectral density given by kTR (where k is Boltzmann's constant)In order to obtain a maximum range value which would be realizible evenunder adverse conditions, the following parameters w e r e used in equation (2).Ta antenna effective noise temperature 100 K corresponding tonear horizon antenna pointing at 5GHz (see for example ref. 11)& radar receiver overall R F losses -4dB (a somewhat pessimistic value to cover all sites; can be a s low as ldb in whichcase maximum range is increased by a factor of approximatelyfl)Lp -3dB for linearily polarized FPS-16 radars (see Table 1)TL TR 290 KF radar receiver noise figure a s tabulated in Tables 1 and 2.7

The noise spectral density for each site is given by:anwhere: kTe ( w a t t s b z )k Boltzmann's constant 1.38 xTe effective noise temperature(OK)(3)Joules/ O Kas determined by equation (2).The mean noise power is then obtained by multiplying equation 3 by thereceiver equivalent noise bandwidth, B, as given in tables 2 and 3. That is, themean noise power, N , is given by:The range, R , in equation (1)is then calculated for two values of singlepulse signal-to-noise ratio (S/'IJ), namely, that minimum value assuring highprobability of acquisition (10dB) and a value which assures high accuracytracking (2OdB). The FPQ-6 (and its transportable counterpart the TPQ-18)employ video integration of up to 100 pulses. However, the lOdB minimumS/N considered here is the single pulse value required to assure reliableautomatic acquisition (99.5% probability of acquisition in 0.2 seconds) by theauxiliary range tracking subsystem of the FPQ-6 (and TPQ-18) or the minimumreliable tracking signal for the FPS-16 (and MPS-25) (ref. 5). In all cases a20dB single pulse S/N will assure high accuracy tracking. If non-coherent(i.e. video) pulse integration is utilized the range for high accuracy track willbe increased by the factor N", where N represents the number of pulses integrated. FPQ-6 video integration is operator selectable in nine steps fromN 3 to N 100, hence the single pulse 20dB S/N is conservative for this radar.Table 4 summarizes the C-band beacon tracking capability of the land aswell as insertion and injection ship radar systems.5.2 SKIN TRACKDuring spacecraft reentry the Apollo ships Watertown (T-AGM-6) andHuntsville (T-AGM-7) will be capable of skin tracking the C M at C-band frequencies. A s indicated in section 3.0, these ships a r e equipped with the "CAPRI"8

-00.-**0.E.C00aNL0-0C.-2L9

and "modified CAPRI" C -band radar systems respectively. A s indicated inFigure 1 (ref. 1 2 ) , the calculated C M c r o s s section, in the absc-nce of an ionplasma sheath, would generally equal o r exceed 1 square-meter. Thus the reentry ships skin tracking calculation is based on a 1 square-meter Apollo CMcross section. The maximum range varies as the fourth root of c r o s s section,hence a factor of 1 0 increase in c r o s s section, represents a range increasefactor of approximately 2. The effect of plasma formation upon Apollo spacecraft reentry is a subject of continuing study (see for example ref. 13).The maximum single pulse range for skin tracking can be estimated fromthe well known "radar range equation" which can be written as:-rwhere:I,P, peak radiated radar transmitter powerGT GR radar antenna gainLR radar receive R F lossesLT radar transmit R F lossesLp polarization lossA, equivalent radar cross section ( m 2 )and all other parametersa r e as defined in equations 1 through 4.For the purpose of skin track calculations for the two Apollo reentry shipsit is assumed that one-way RF losses (LR or LT) can be held to 1dB.Because of uncertaintif associated with C M c r o s s section during reentrythe maximum ranges presented in Table 4 must necessarily be considered ascoarse estimates of C-band skin track capability by the Apollo reentry ships.The maximum 1 square-meter range of the CAPRI for a 10 dB S/N is calculated as 140 n.rni. which is comparable to the 150 n.mi., 1 square-meter,maximum skin tracking range RCA presents for the land based FPS-16 withthe latter using a 16 foot antenna (ref. 5). The shipboard CAPRI, while usinga smaller antenna (12 foot diameter) has a lower receiver noise figure (5dB10

10,000 cAFTER R. L. DANIELSNORTH AMERICANREPORT SID 63-7465 JULY 1963(REF. 12)I10001000fJ101 .o0.1I040801601202002405Figure1. Apollo Radar Cross Section, Ao, versus Aspect Angle, 8 , a t 5.5 GHz11280

compared to 11 dB for the standard FPS-16). Both radars employ 1 megawattpeak power transmitters.6.0 SUMMARYIt is seen (Table 4) that during the Apollo lunar mission, 15 of the 25 landand ship C-band tracking radars considered can track the I U unambiguously upto and during IU jettison at a nominal altitude of 6,200 n.mi. The reentry shipWatertown employing the CAPRI radar can skin track a 1 square-meter targetto 140 n.mi. whereas the Huntsville, utilizing the modified CAPRI, can track1 square-meter to approximately 350 n.mi. It is expected that the lunar mission C M upon reentry will, except for possible anomalous effects due to theion sheath (ref. 13), present a cross section in excess of 1 square-meter.The angular tracking limits listed in Table 4 are based upon publishedRCA radar system characteristics. However the tracking accuracies listed inTable 4 are conservative e r r o r estimates currently used by the Apollo Navigation Working Group (GSFC-MSC) and are not to be construed as equipmentspecifications.REFERENCES1. Office of Manned Space Flight, "Support Requirements Reference Handbookf o r the Apollo Saturn V Programs,'' NASA, Washington, D. C., July 1966.2."Program Support Requirements Document, Apollo-Saturn V," NASA, asrevised through June 1 2 , 1967.3. Manned Space Flight Network Ground Systems, NASA Technical ManualMG-401, Section 1, P. 11, February 1967.4. "Reference Data for Radio Engineers ,IT International Telephone and Telegraph Corporation, P. 957, July 1961.5. RCA, !'Range Instrumentation Systems and Equipment,'' Defense Electronics Products, M i s s i l e and Surface Radar Division, Moorestown, NewJersey, updated through December 1966.6. RCA, "Special Progress Report for Modified C -band Reentry AcquisitionRadar," Defense Electronics Products, Missile and Surface Radar Division, Moorestown, New Jersey (under NASA Contract NAS5-10033) July 13,1967.12

REFERENCES (Continued)7. Moore, J. R., "Analysis of the Apollo Reentry Radar", Goddard SpaceFlight Center, Greenbelt, Maryland, X-507-67-281, June 1967.8. RCA, "Radar Set AN/FPS-16(V) Technical Manual," prepared for NASAunder NAS5-9720, Vol. 1, as revised through June 15, 1967.9. "Program Support Requirements Document, Apollo-Saturn IV," NASA, asrevised through July 24,1967.10. Barton, D. K., "Radar System Analysis," Prentice Hall, Inc., EnglewoodCliffs, New Jersey, P. 124,1964.11. Blake, L. V., "Low Noise Receiving Antennas," Microwaves, P. 21, March1966.12. Daniels, R. L., "Final Report On Apollo Plasma Reentry Studies," NorthAmerican Aviation, Inc., Space and Information Systems Division, SID 63746, P. 181, 5 July 1963.13. Marini, J. W., "On the Decrease of the Radar Cross Section of the ApolloCommand Module Due to Reentry Plasma Effects,'' NASA, Goddard SpaceFlight Center, X-507-67-283, June 1967.13

Merritt Island Patrick Air Force Base Grand mama Island San Salvador Island Grand Turk Island Antiqua Bermuda Grand Canary Island Ascension Island Pretoria, South Africa Carnarvon, Australia Woomera, Australia Kauai, Hawaii Point Arguello California White Sands Eglin Air Force Base 'Radar Tme FPS-16 TPQ-15 FPQ-6 FPS-16 TPQ-1f FPS-16 TPQ-1f FPQ-6

Related Documents:

Jan 22, 2020 · Apollo 1050 Apollo 1500 Apollo 1550ETL Apollo 1650 Apollo 1650ETL Apollo 3500ETL Apollo 3600ETL Apollo 633 Control Board Apollo 634 Control Board Apollo 635 Apollo 636 Apollo 7000ETL Apollo 835 Apollo 836 Aprimatic ALZO 55 with Control board T230 A

SYNTHETIC APERTURE RADAR (SAR) IMAGING BASICS 1.1 Basic Principles of Radar Imaging / 2 1.2 Radar Resolution / 6 1.3 Radar Equation /10 1.4 Real Aperture Radar /11 1.5 Synthetic Aperture Radar /13 1.6 Radar Image Artifacts and Noise / 16 1.6.1 Range and Azimuth Ambi

Subaru XV specifications1 MODEL 2.0i AWD 2.0i-L AWD 2.0i Premium AWD 2.0i-S AWD Hybrid AWD CO 2 emissions (ADR 81/02) combined (g/km) 159 147 Symmet

APOLLO Page 2. APOLLO STAGES (OLD & NEW!)Currently, Apollo Presents takes place primarily on two stages: The Apollo Main stage - A 1,500-seat, state-of-the-art Theater; and The Apollo Soundstage - A flexible, intimate space with audience capacity of up to 175. However, 2020 will bring the Apollo’s o

Speakers, Dim, and Mono functions as well as input and output metering capabilities. Expands Your System Thanks to Apollo Expanded software, users of Thunderbolt-equipped Apollo Twin, Apollo 8, Apollo 8p, and Apollo 16 audio interfaces can combine up to four Apollos and six total UAD-2 devices — adding I/O and DSP as your studio grows.

complete hardware-related details about one specific Apollo model. Included are detailed descriptions of all hardware features, controls, connectors, and specifications. Note: Each hardware manual contains the unique Apollo model in the file name. Apollo Software Manual The Apollo Software Manual is the companion guide to the Apollo hardware .

bistatic radar geometry.27 Radar-absorbent material augments fuselage shaping by absorbing radar energy and reducing the strength of the radar echo.28 Future innova-tions may allow stealth aircraft to actively cancel radar echo by retransmitting radar energy and/or by ionizing boundary layer air around the fuselage.29 Counters to Stealth

Apollo std. Apollo lg dia." PTC3 Performance 4 "2 2 OT-Bass 2 2 TH-others" "Trophy Plus Vensura " Cyclone Bay Pro II HR Titan 4 "Ballistic XL Apollo 4 Blade" TRO4 Reliance Turbo 1 "Laser II Vengeance " "SSP Viper " Advantage II New Saturn "Ballistic Apollo std. Apollo