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M LONG TRANSVERSAL TRACE CLOSE TO A JOINT OF A HIGHWAY CONCRETE DECK 4OP 0OLARIZATION PARALLEL TO THE DOWELS BOTTOM 0OLARIZATION PERPENDICULAR TO THE DOWELS #OURTESY )%% #$ #$ "$ % # $# # # |
GRATION TIME OF S RESULTING IN A NOMINAL DOPPLER FILTER BANDWIDTH OF (Z .OISE . SAMPLES WERE TAKEN FROM THE MAXIMUM DOPPLER BIN TARGET SAMPLES 4 ON THE TARGET PEAK AND "RAGG LINE AMPLITUDES ! AND 2 FROM THE CLUTTER PEAKS CORRESPONDING TO THE APPROACHING AND RECEDING RESONANT OCEAN WAVES AS DESCRIBED IN 3ECTION . 4 ! AND 2 ARE PLOTTED IN &IGURE A 4HE SUB |
A different approach to the problem is line-of-sight, or tilt, stabilization. Instead of mount- ing the antenna on a level platform, the antenna is tilted about the elevation axis so as to automatically maintain the beam pointed at the horizontal. (The beam direction can also be maintained constant at whatever angle above or below the horizon is desired.) The line of sight is thereby stabilized. |
SPACE 0ROPAGATION 4HE SIMPLEST CASE OF ELECTROMAGNETIC WAVE PROPAGA |
FIG. 17.1 Clutter and target frequency spectrum from a horizontally moving platform. the angle between the velocity vector and the line of sight to the target. |
?'he arc loss might be f to 1 dB in tubes filled with water vapor and 0.1 dB or less with argon filling. On reception, the TR tube introduces an insertion loss of about f to 1 dB. The life of a conventional TR is limited by the keep-alive, the amount of water vapor in the gas filling, and by disappearance, or " clean-up," of the gas due to the gas molecules becoming imbedded in the walls of the TR tubes4' The end of life of a TR tube is determined more by the amount of leakage power which it allows to pass than by physical destruction or wear. |
(4.8)], but it also allows a sharper low-frequency cutoff in the frequency response than might be obtained with a cascade of single-delay-line cancelers with sinn nf,Tresponse. The blind speeds of two independent radars operating at the same frequency will be different if their pulse repetition frequencies are different. Therefore, if one radar were " blind " to moving targets, it would be unlikely that the other radar would be " blind" also. |
20, pp. 79-82, June, 1977. 2 1. |
In Proceedings of the 2014 IEEE Geoscience and Remote Sensing Symposium, Quebec City, QC, Canada, 13–18 July 2014; pp. 930–933. 7. |
. Radar System Engineeri ng Chapter 8 – Pulse Radar 55 b c fa d e Σ Figure 8.8 Time behaviour of moving targets ( ↓) on an oscilloscope. For automatic analysis the fact that fixed -target echoes are constant from pulse to pulse is used. |
Because of the spherical symmetry of l he lens, the focusing property does not depend upon the direction of the incident wave. The beam may be scanned by positioning a single feed anywhere on the surface of the lens or by locating many feeds along the surface of the sphere and switching the radar transmitter or receiver from one horn to another. The Luneberg lens can also generate a number of fixed beams. |
4.8). The output of the IF amplifier is fed to I and Q phase detectors. The analog signals from the phase detectors are converted into 10-bit digital words by A/D converters. |
TUDE DISTRIBUTION 4HE DIFFERENCE CHANNELS ARE TREATED SIMILARLY WITH INDEPENDENT AMPLITUDE WEIGHTING 4HIS METHOD MAY BE EXTENDED TO INCLUDE COMBINATIONS IN THE OTHER PLANE !MPLIFICATION ON RECEIVING OR ON BOTH RECEIVING AND TRANSMITTING MAY BE CON |
At low-power levels, gridded tubes must compete with the solid-state transistor. l'he grid-corttrolled tube is characterized as being capable of high power, broadband, low or 113oderate gain, good efficiency, atid inherent long life. Unlike other microwave tubes, the grid-controlled tube can operate, if desired, with a linear rather than a saturated gain charac- teristic. |
LIMITED TECHNIQUES OF WHICH LASER ALTIMETERS ARE EXTREME EXAMPLES CIRCUMVENT THESE PROBLEMS BUT MAY IMPLY THEIR OWN SET OF DISADVANTAGES ! MAJOR POTENTIAL APPLICATION OF RADAR ALTIMETRY IS TO MONITOR THE HEIGHT OF EXTENSIVE ICE SHEETS AS FOUND IN 'REENLAND OR !NTARCTICA !PPROXIMATELY OF THESE LAND |
POLAR |
In fact, C now starts discharging through R2 and the point M, and therefore the potentials of G2 and G3 will change slowly untla . state similar to (6) is reached. At this instant the slow change in G3 and G2 voltages acts as a disturbance, and another violent change (the ‘flop’) takes place in the . |
IEEE, vol. 54, pp. 237-243, February 1966. |
TheBritishrealized theadvantages tobegainedfromthebetterangular resolution possible atthemicrowave frequencies, especially forairborne andnavalapplica tions.Theysuggested thattheUnitedStatesundertake thedevelopment ofamicrowave AI. 12 INTRODUCTION TO RADAR SYSTEMS radar and a microwave antiaircraft fire-control radar. The British technical mission demonstrated the cavity-magnetron power tube developed by Randell and Boot and furnished design information so that it could be duplicated by United States manufacturers. |
Mookerjee and F. Reifler, “Reduced state estimator for systems with parametric inputs,” IEEE Trans . Aerospace and Electronic Systems , vol. |
BOUNCE TARGETS ARE REJECTED 3UCH A SYSTEM CAN THEREFORE GIVE A MEASURE OF SUPPRESSION OF RAIN ECHOES IDEALLY AMOUNTING TO LOG E E |
The envelope oftheechoes istheantenna pat- tern (voltage two ways), and the maximum pulse-to-pulse variation Ay occurs atthe point where the antenna pattern has itsmaximum slope. Thus Aycan bereadily calculated ifaGaussian error curve isused asan approximation totheactual antenna curve. The result canbewritten in theform Ay 1.43 Yo=?l’(7) where y.isthemaximum received voltage and nisthenumber ofpulses transmitted while the antenna rotates through anangle equal tothe. |
Thisfilterpassesthecluttercomponent atdc,hence ithasnoclutterrejection capability. (Itsoutputisuseful,however, insomeMTIradarsfor providing amapoftheclutter.) Thefirstnullofthefilterresponse occurswhenthenumerator iszero,orwhenf= liNT.Thebandwidth between thefirstnullsis21NTandthehalf-power bandwidth isapproximately O.9INT (Fig.4.23). Whenk=I,thepeakresponse occursat/=liNTaswellasf=liT+liNT,21T+ liNT,etc.Fork=2,thepeakresponse isatf=2INT,andsoforth.Thuseachvalueofthe indexkdefines aseparate filterresponse, asindicated inFig.4.23,withthetotalresponse covering theregionfromf=0tof=liT=/p.Eachfilterhasabandwidth of21NTas measured between thefirstnulls.Because ofthesampled natureofthesignals,theremainder of thefrequency bandisalsocovered withsimilarresponse, butwithambiguity. |
BASED DISPLAY TECHNOLOGY )N PARTICULAR MODERN WELL |
2409–2412. 25. Yu, Y.; Acton, S. |
Conv. Rec. , vol. |
If the sidelobes of the individual filters of the doppler filter bank can be made low enough, the inclusion of the delay-line canceler ahead of it might not be needed. MTIANDPULSE DOPPLER RADAR123 ingtothek=0toN-1weighting asgivenbyEq.(4.13).(Thisisanalogous togenerating N independent beamsfromanN-element arraybyuseoftheBlassmultiple-beam arrayasin Fig.8.26.)Whengenerating thefilterbankbydigitalprocessing itisnotnecessary literally to subdivide eachoftheNtaps.Theequivalent canbeaccomplished inthedigitalcomputations. Thegeneration bydigitalprocessing ofNfiltersfromtheoutputsofNtapsofatransver salfilterrequires atotalof(N-1)2multiplications. |
T. Vetterling, and B. P. |
The spectral spread in velocity is with respect to tlie mean velocity, which for ground clutter is usually zero. Rain and I I I I1 l Ill 1 I I I11111 I I I I1111 Sparse Wooded hills Wooded hills Sea echo Rain woods 10 knots 40 knots Chof f - - - - - - I I I 1 11111 I I I 1 11 111 I I I1 1111~ uv = rms velocity spread, rn/s Figure 4.30 Plot of double-canceler clutter improvement factor [Eq. (4.26)] as a function of a, = rms velocity spread of the clutter. |
The lowest mode inround guide has diametral rather than axial symmetry, FIG.11.13 .—Waveguide rotary joint using round waveguide andaxially symmetrical mode. and ifpresent toanappreciable extent will cause serious variation in voltage standing-wave ratio asafunction ofangle ofrotation. The transitions from rectangular toround guide aredesigned toavoid exciting the undesired mode asfaraspossible. |
ELEVATION ANTENNA BEAM USED FOR MONOPULSE ANGLE ESTIMATION D"C DECIBELS WITH RESPECT TO THE CARRIER$# DIRECT CURRENT$&4 DISCRETE &OURIER TRANSFORM&)'52% 3INGLE |
Appl. Meteorol. , vol. |
136-138 quantization, 120 Efficiency: klystron. 204 tube.191 Electromechanical phaseshifters.297-298 Electron-bombarded semiconductor (EBS) device.21721R Electron gun.201 Electronic counter-countermeasures. 542. |
TO |
TION FOR AIRCRAFT TRACKING IN THE UPPER PART OF THE (& BAND 4HE EXPERIMENTAL &RENCH /4( RADAR .OSTRADAMUS n LIKEWISE EMPLOYS A SINGLE ANTENNA ARRAY CONFIGURED AS THREE HORIZONTAL ARMS OF LENGTH M RADIATING FROM A CENTRAL CONTROL CENTER THOUGH ONLY A SUBSET OF ELEMENTS ARE USED TO TRANSMIT WHEREAS ALL OF THE ELEMENTS ARE USED FOR RECEPTION 3UCH TRULY MONOSTATIC DESIGNS HAVE THE SPECIAL ADVANTAGE THAT THE OUT |
REFLECTED SIGNAL CAN INCREASE SIGNIFICANTLY THE RANGE OF A 6(& RADAR 3OMETIMES THIS EFFECT CAN ALMOST DOU |
TUDE TO SEVERAL INDIVIDUALS WHO HELPED THEM IMMENSELY IN THE PREPARATION OF THIS CHAPTER &IRST TO -R 'REGORY 4AVIK OF .2, FOR HIS THOROUGH REVIEW OF THIS CHAPTER AND THE MANY EXCELLENT COMMENTS HE MADE .EXT TO $R &RED (ARRIS OF 3AN $IEGO 3TATE 5NIVERSITY AND -R 2ICHARD ,YONS WHO GRACIOUSLY REVIEWED SECTIONS OF THE CHAPTER AND OFFERED SEVERAL SUGGESTIONS ALL OF WHICH WERE INCORPORATED , |
13065–13083, 1986. 32. A. |
SHOULDER GEOMETRY OR WHEN THE BASELINE IS SMALL )N THESE CASES TRANSMIT AND RECEIVE BEAMS BECOME MORE CLOSELY ALIGNED IN A . |
(14.2) into(14.1)givesthecross-range resolution as bcr=RA/D Thebeamwidth ofasynthetic aperture antenna ofeffective lengthLeissimilarly 0$=klJ2Le(143) (14.4) Thefactor2appears inthedenominator becauseofthetwo-way propagation pathfromthe .1Iltenna "element" tothetargetandbackascompared withtheone-way pathofaconven tit,nalantenna. Asaconsequence ofthetwo-way paththephasedifference between theequally spacedelements ofasynthetic arrayistwicethatofaconventional arraywiththesame spacing. (Thetermssynthetic arrayandsynthetic aperture areusedinterchangeably here.) Againthefactorkwillbetakentobeunity. |
I. I. Kat1, and L. |
Thetwo-frequency CWtechnique formeasuring rangewasdescribed asusingthedoppla frequency shift.Whenthedoppler frequency iszero,aswithastationary target,itisalso possible, inprinciple, toextractthephasedifference. Ifthetargetcarriesabeaconorsome otherformofecho-signal augmentor, thedoppler frequency shiftmaybesimulated bytrans latingtheechofrequency, aswithasingle-sideband modulator. Thetwofrequencies ofthetwo-frequency radarweredescribed asbeingtransmitted simultaneously.63 Theymayalsobetransmitted sequentially insomeapplications byrapidly switching asingleRFsource. |
E. Ruvin, “Recent advances in the synthesis of comb filters,” in IRE Nat. Conv. |
179. G. A. |
This was due to variations in the equipment itself and also to component failures, poor tuning and so on. The effects of radar propagation and sea returns, which were only just beginning to be understood, and variations in targetradar cross section also contributed. Also very signi ficant were the great variations in operator skill levels and the lack of concentration during long operations due to fatigue. |
Another significant application of radar that depends on the doppler shift is obser - vation of the weather, as in the Nexrad radars of the U.S. National Weather Service (Chapter 19) mentioned earlier in this chapter. Both the SAR and ISAR can be described in terms of their use of the doppler fre - quency shift (Chapter 17). |
DETECTION IMAGERY FOCUSED 3!2 DATA MAY BE PRE |
TO |
'(Z PERFORMANCE CURVES FOR A MM PERIPHERY 'A!S 0(%-4 &%4 OPERATING AT 6 USING A #7 DUTY WAVEFORM. 3/,)$ |
The stretch processing implementation for the Millimeter Wave radar (MMW) located at Kwajalein Atoll is described by Abouzahara and Avent.64 The MMW radar operates at a carrier frequency of 35 GHz using waveforms with a maximum swept bandwidth of 1000 MHz and pulsewidth of 50 µs. The LFM slope for the transmit waveform is αµµ = = =B T100020MHz 50sMHz/s The stretch processing bandwidth is Bp = 5 MHz. The width of the stretch processing time window is ∆t= =50 25MHz 20MHz ssµµ. |
38.Peeler,G.D.M.,andD.H.Archer:AToroidal Microwave Reflector, IRENelli.Conr.Rt'Cord,vol.-t, pt.I,pp.242-247, 1956. 39.Kelleher, K.S.,andH. H.Hibbs:ANewMicrowave Reflector, Nal'alResearch Lah.Rept.4141,1953. |
MIT-9, pp.472-480, November, 1961. 47.Knerr,R.H.:AnAnnotated Bibliography ofMicrowave Circulators andIsolators: 1968-1975,/EEE Trans.,vol.MIT-23, pp.818-825, October, 1975. 48.Gawronski, M.J.,andH.Goldie:200WMICL-BandReceiver Protector, Microwave J.,vol.20,pp. |
CIVIL MARINE RADAR 22.196x9 Handbook / Radar Handbook / Skolnik / 148547-3 / Chapter 22 can be initiated. All tracked targets are displayed on the screen with their associated velocity vectors. Tracked targets may be selected by the user such that all information concerning that target, including CPA and TCPA, is displayed on the data panel of the radar screen. |
PLY ANDOR MODULATOR DELIVERING POWER TO THE TUBE 3INCE * OF ENERGY CAN USUALLY CAUSE DAMAGE TO AN 2& TUBE OR THE SWITCHING DEVICE AND SINCE THE CAPACITOR BANK FOR AN ACTIVE |
A rectangular display in which a target appears as a laterally centralized blip when the radar antenna is aimed at it in azimuth, and wings appear to grow on the pip as the distance to the target is diminished; horizontal and vertical aiming errors are respectively indicated by horizontal and verti cal displacement of the blip. fl-scope. A B-scope modified to include indication of angle of elevation. |
HERTZ PHASE ;SIGNAL= FOR EACH BASELINE PAIR EAST WEST AND NORTH SOUTH 4HIS PHASE SIGNAL IS COMPARED WITH A |
M.: "Probability and Information Theory, with Applications to Radar," chap. 6, McGraw-Hill Book Co., New York, 1953. 6. |
TION OF ENERGY WITHIN A SLENDER FICTITIOUS TUBE CALLED A RAY 4HE DIRECTION OF PROPAGATION IS ALONG THE TUBE AND CONTOURS OF EQUAL PHASE ARE PERPENDICULAR TO IT )N A LOSSLESS MEDIUM ALL THE ENERGY ENTERING THE TUBE AT ONE END MUST COME OUT THE OTHER END BUT ENERGY LOSSES WITHIN THE MEDIUM MAY ALSO BE ACCOUNTED FOR !N INCIDENT WAVE MAY BE REPRESENTED AS A COLLECTION OF A LARGE NUMBER OF RAYS AND WHEN A RAY STRIKES A SURFACE PART OF THE ENERGY IS REFLECTED AND PART IS TRANSMITTED ACROSS THE SURFACE 4HE AMPLITUDE AND PHASE OF THE REFLECTED AND TRANSMITTED RAYS DEPEND ON THE PROPERTIES OF THE MEDIA ON EITHER SIDE OF THE SURFACE 4HE REFLECTION IS PERFECT IF THE SURFACE IS PERFECTLY CON |
FREQUENCY AND NEGATIVE |
Animportant advantage ofthe limiting receiver isthat the output video signals have ai-ange ofamplitude extending from noise only upto the limit level. This small dynamic range makes iteasy todesign the cancellation circuits. For thelin-log receiver, thedynamic range is6to 12dbgreater under conditions ofequal performance. |
Any use is subject to the Terms of Use as given at the website. MTI Radar. 2.90 RADAR HANDBOOK 6x9 Handbook / Radar Handbook / Skolnik / 148547-3 / Chapter 2 by the maximum likelihood estimate.49 For a single-pulse signal-to-noise ratio S1 and n pulses in a CPI, the Cramer-Rao lower bound for the accuracy of the doppler frequency estimate is σ πf S n n S n n PRF= ⋅ ⋅ ⋅ ⋅ −= ⋅ ⋅ −6 2 103898 112 12( ). ( ) (2.65) Since the maximum likelihood estimation procedure tends to require a tedious computational burden, a simplified approach for estimating the doppler frequency is highly desirable. |
TRACK ASSOCIATION )T IS POSSIBLE TO MAKE SIMPLE COMPARISONS BETWEEN THE ACCURACY OF DETECTION FUSION AS OPPOSED TO TRACK FUSION FOR EQUIVALENT USE OF DATA BANDWIDTH TO EXCHANGE RADAR DATA 7HEN 2/5 IS PLOTTED AS A FUNCTION OF THE POSITION GAIN @ IT HAS THE hBATHTUBv SHAPE SHOWN BY THE SINGLE RADAR CURVE IN &IGURE 4HE LEFT |
ING VERY HIGH ANTENNA GAINS ARE MISSILE DEFENSE RADAR AND SPACE |
TAL CONDITIONS FOUND ON SMALL CRAFT )NSTEAD MINI JOYSTICKS OR SIMPLE FOUR |
Figure 3.4 Refraction of waves in the inhomogeneous atmosphere and the enlargem ent of the range of coverage. . Radar System Engineering Chapter 3 – The Radar Equation 17 Through this bending, as it is taken into account in physical optics, the visibility & view under the horizon with be expanded. |
Plant, and W. C. Keller, “Comparison of optically-derived spectral densities and microwave cross-sections in a wind-wave tank,” J. |
With other phase and frequency relationships, there is still a loss with a single channel MTI that can be recovered by the use of both the I and Q channels. An extreme case where the blind phase with only a single channel results in a complete loss of signal is when the doppler frequency is half the prf and the phase relationship between the two is such that the echo pulses lie on the zeros or the doppler-frequency sine wave. This is not the condition for a blind speed but nevertheless there is no signal. |
E. Willey54 © IRE 1962. Courtesy of Bendix Radio .) ch13.indd 23 12/17/07 2:39:52 PMDownloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2008 The McGraw-Hill Companies. |
Ithas proved, however, tobenooperational limitation. Height-finding bysuch asetisreasonably accurate. The results ofa calibration flight with anexperimental model ofthe AN/T PS-10 are shown inFig. |
--" Ê76 |
181. R. K. |
Pulses from theupper half oftheantenna rotation arecompared with those from the lower half bymeans ofinte- grating circuits, and theoutput difference isused todisplace thespot ofan error indicator (Sec. 6.8). APPI isprovided forgeneral reporting, and two range scopes, one covering the full range ofthe setand one an expanded A-scope, make itpossible todetermine target range and to eliminate from thesignal-comparison circuits allechoes except those from thetarget whose altitude isbeing determined. |
- !S DISCUSSED IN 3ECTION THE -4$ USES A WAVEFORM CONSISTING OF COHERENT PRO |
TIPLE RECEIVE ANTENNA CHANNELS AND PULSES 4HIS WEIGHTING DYNAMICALLY TAILORS A FILTER RESPONSE IN ANGLE AND BISTATIC DOPPLER TO SUPPRESS GROUND CLUTTER REFLECTIONS $IGITAL BEAMFORMING IS REQUIRED FOR THIS OPERATION /THER NECESSARY ELEMENTS INCLUDE A MEANS TO ESTIMATE THE SPATIO |
Houze, Jr., and J. D. Locatelli, “Real-time wind measurement in extratropical cyclones by means of doppler radar,” J. |
However, there is a loss of 3 dB SNR at the receiver inputs although this loss is partly regained by coherent addition of the 2-signal information. The design of the microwave resolver must minimize loss through the device, and high preci- sion is required to minimize cross coupling between azimuth and elevation chan- nels. The resolver performance is improved by the use of ferrite switching de- vices to replace the mechanical rotating coupler. |
ART OF RADAR CAN AMELIORATE THESE PROBLEMS BUT NOT WITHOUT SOME UNDESIRABLE SIDE EFFECTS -ANY UNWANTED POINT TARGET RETURNS HAVE CHARACTERISTICS SIMILAR TO THE RETURNS FROM WANTED TARGETS AND THE UNWANTED RETURNS MAY OUTNUMBER RETURNS FROM DESIRED TAR |
Óä°{ 2!$!2 (!.$"//+ #ONSIDER THE SET OF TASKS AND $)2S SHOWN IN &IGURE 4ASK WOULD REQUIRE ONLY SHORT #)4S n S SAY IF THE AIRCRAFT IS ASSUMED TO BE LARGE AND WOULD NEED REVISITS PERHAPS EVERY MINUTE AS THE FLIGHT IS NOT EXPECTED TO MANEUVER SO THE TRACK WILL BE WELL |
IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by the author, nor is IEC in any way responsible for the other content or accuracy therein. REFERENCES 1. International Maritime Organization, www.imo.org. |
J8. Barbe, D. F., and W. |
More recent optical flow or motion estimation algorithms can be investigated as an alternative to the one utilized in this work. The chosen optical flow method is suitable for the tested dataset and performs adequately as expected since it takes into account the intensity changes between images. The choice of K-SVD over PCA increased the computational complexity while allowing flexibility over the details of the change maps by changing the dictionary size and the number of non-zero coefficients. |
56. Works, G. A.: Advanced Onboard Signal Processor, IEEE EASCON '8O Rec., p. |
Unlike vacuum tubes, the peak power that c;irl hc ;icliicvcd wit 11 Itarrow pillse widtlis is only about twice the CW power.28 This res~rlts in tlic tnicrowave trntisistor t~citig operated with relatively long pulse-widths and high duty cyclcs. For air-s~~r.vcill;iricc radar applic;itio~l. pulse widtlis rniglit be many tetis of r~lic~~oscculicls or niorc. |
vol. 36, pp. 1652-1660, 1958. |
SIDELOBE ANTENNA CAN BE CONSIDERED IN TWO PARTS #HOOSE THE CORRECT ILLUMINATION FUNCTION TO ACHIEVE THE DESIRED DESIGN ERROR |
MATICALLY WITH ONLY MODEST DEPARTURES FROM OPTIMUM SETTINGS 4HUS THERE IS A DEMAND FOR TWO INGREDIENTS I INFORMATION ABOUT THE ENVIRONMENT AND II A MECHANISM OR AT LEAST A STRATEGY FOR USING THAT INFORMATION TO CONTROL THE RADAR PARAMETERS !T THE VERY MINIMUM (& SKYWAVE RADARS MUST MAINTAIN A REAL |
Leung, Z. Hu, and M. Blanchette, “Evaluation of multiple radar target trackers in stressful environments,” IEEE Trans . |
ch06.indd 25 12/17/07 2:03:25 PMDownloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2008 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Radar Receivers. |
WAY PROPAGATION WITH RESPECT TO TWO |
SURVEILLANCE NEEDS 4HEY HAVE BEEN DESIGNED FOR REMOTE OPERATION IN HARSH ENVIRONMENTS AND WITH THEIR ESTABLISHED LOGISTICS SUPPORT BUILT |
Application to live data acquired with a ground-based phased array radar,” Proc. of IEEE 2004 Radar Conf ., Philadelphia (USA), April 26–29, 2004, pp. 486–491. |
Any use is subject to the Terms of Use as given at the website. Pulse Doppler Radar. PULSE DOPPLER RADAR 4.516x9 Handbook / Radar Handbook / Skolnik / 148547-3 / Chapter 4 29. A. |
In addition to external sources of interference, the radar designer must be con- cerned with internal signal sources. MTI and pulse doppler radars are particularly dB BELOW OUTPUT AT CENTER OF PULSE RELATIVE VOLTAGE NINE-POLE GAUSSIAN INFINITE-POLE GAUSSIAN FIVE TUNED STAGESRECTANGULAR FIVE-POLE GAUSSIAN ONESINGLE-TUNEDSTAGE TWO TUNEDSTAGES . susceptible to any such internal oscillators that are not coherent, i.e., that do not have the same phase for each pulse transmission. |
PL PLSSIN SIN PP |
For a given antenna size (antenna aperture), narrower beam widths are obtained when using shorter wavelengths. For a given wavelength, narrowerbeam widths are obtained when using larger antennas. The slotted waveguide antenna has largely eliminated the side-lobe problem. |
For good range resolution, TT must be small, which requires that An1 be large. (Target range change during the dwell limits the minimum T,.) 5. To minimize the transmitter duty cycle and hence the average-power vari- ation between PRFs, An1 should be relatively large. |
FREQUENCY RADARS BUT THE DOPPLER RESOLUTION CAN BE EXCEEDINGLY FINE 4HE MAGNITUDE AND DOPPLER DISTRIBUTION OF THE ECHOES FROM THE DISTANT %ARTHS SURFACE OFTEN TERMED BACKSCATTER THOUGH THAT TERM SHOULD BE RESERVED FOR MONOSTATIC RADARS ARE MAJOR FACTORS IN SETTING SYSTEM DYNAMIC RANGE SPECTRAL PURITY AND SIGNAL PROCESSING REQUIREMENTS#HAPTER . Óä°Ó 2!$!2 (!.$"//+ &OR EFFECTIVE RADAR OPERATION ENVIRONMENTAL PARAMETERS THAT AFFECT RADAR PERFORMANCE NEED TO BE DETERMINED IN REAL TIME DEFINED AS THAT INTERVAL IN WHICH THERE ARE NO LARGE |
The received Y* pulse train of finite duration to has a frequency spectrum (which can be found by taking the Fourier transform of the waveform) whose width is proportional to l/to. Therefore, even if the clutter were perfectly stationary, there will still be a finite width to the clutter spectrum because of the finite time on target. If the clutter spectrum is too wide because the observation time is too short, it will affect the improvement factor. |
G. Long, and A. W. |
(after T. LeToan12 © IEEE 1982 ) ch16.indd 38 12/19/07 4:56:08 PMDownloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2008 The McGraw-Hill Companies. All rights reserved. |