text
string |
|---|
4.2.2 Modulator type 158 This was similar to modulator type 64 used on ASV Mk. III, but with an increased power output of 550 kW peak. A bridge recti fier generated a DC power supply of 7 kW and from this pules of 1 μs duration and recurrence frequency 666 c/s were formed using a CV125 spark gap and a DN39C delay line. |
The radial velocity components of the three system ele- ments contribute to the doppler shift of the re- ceived signal.TARGET MISSILE . It should also be clarified what is meant by approaching and receding tar- gets within the missile doppler spectrum. A target approaching the missile will yield a signal at a frequency above that of MLC (which corresponds to missile velocity). |
98. R. J. |
, 104. Wickenden, B. V. |
GULAR AND THE DIFFERENCE IN RANGE ACROSS A RESOLUTION ELEMENT IS NEGLIGIBLE THE EXPRES |
Weil and Merrill Skolnik 10.1 INTRODUCTION Role of the Transmitter in Radar. If a radar systems designer could ask for anything he or she wanted in a radar transmitter, that wish might be something like the following: Provide the necessary transmitted energy with the needed average and peak power, as well as the required stability and low noise for good doppler process - ing; operate with high efficiency; have wide bandwidth and be easily tunable; be readily modulated in amplitude, frequency, or phase as necessary; have high reliability and long life; require minimum maintenance; have no dangerous X-ray emissions; require no personnel to operate; be of an affordable price; and be of reasonable size and weight for the desired application. Of course, not all of these desirable attributes can be achieved in any given radar trans - mitter application. |
l) It is assumed in this analysis that the lengths of the direct and the reflected paths are almost (but not quite) equal so that the amplitudes of the two signals are approximately the same provided there is no loss suffered on reflection. Hence, if the amplitudes of the two waves differ from one another, it is assumed to be due to a surface-reflection coefficient less than unity. Although the two paths are comparable in length, they are not exactly equal. |
Uhlenheck (eds.): "Threshold Signals," MIT Radiation Laboratory Series. vol. 24, McGraw-Ilill Book Company, New York, 1950, p. |
However, note a few echo sources along a line parallel to, and slightly forward of, the wing trailing edges. If the target rotation had been centered on an aspect angle perpendicular to one of the wings, the leading edge of that one wing would have “lit up.” In the region of the main wing roots, we see heavy concentrations of echo sources. Some of them lie forward of any wing surface. |
DOPPLER CLUTTER IS USED TO COVER ALL THESE PHENOMENA WHERE THE SCATTERERS RESPONSIBLE FOR THE CLUTTER DO NOT HAVE A WELL |
All rights reserved. Any use is subject to the Terms of Use as given at the website. Radar Receivers. RADAR RECEIVERS 6.176x9 Handbook / Radar Handbook / Skolnik / 148547-3 / Chapter 6 Figure 6.5 illustrates typical common and uncommon phase noise components and the resulting mixer output phase noise as calculated using L f L f F f L fC R U '() ( ) | ( )| ( ) = +2 (6.10) where LC(f) = STALO SSB phase noise spectrum common to the receiver and exciter LU(f) = total receiver-exciter uncorrelated STALO SSB phase noise FR(f) = range dependence factor Residue Power and MTI Improvement Factor. |
The/requency response function is proportional to sin2 nh T. A transversal filter with three delay lines whose weights are 1, -3, 3, -I gives a sin 3 nf, T response. This is a four-pulse'canceler. |
Two prototype installations on Wellington VIII aircraft were completed at No. 30 MU in December 1942 and the CCDU work on assessing ASV Mk. III started in January 1943.Airborne Maritime Surveillance Radar, Volume 1 3-3. |
164. J. Wurman and M. |
The motion compensation mainly compensates for the translation motion between the target and the radar. It contains two steps, one is range alignment, and the other is phase compensation [ 8,11]. The raw data-like data R(m,n)is inverted from SLC SAR images and range alignment is a coarse compensation, the raw data-like data R(m,n)no longer implement range alignment and the phase compensation is the main step of ISAR processing in this paper. |
1111. 1.1 I ( IRONl('A1 I Y Sll~l~l~I~l~ I~IIASI~I~ ARRAY ANI'ICNNA IN RAl)Al< 339 42. Sakiotis, N. |
Sensors 2019 ,19, 743 36. Chen, G.; Zhang, Y.; Zeng, R.Q.; Yang, Z.K.; Chen, X.; Zhao, F.M.; Meng, X.M. Detection of land subsidence associated with land creation and rapid urbanization in the chinese loess plateau using time series insar: A case study of Lanzhou new district. |
" AMPLIFIERS ARE BIASED SUCH THAT CONDUCTING CURRENT IN THE TRANSISTOR FLOWS FOR EXACTLY ONE HALF OF THE INPUT SIGNAL VOLTAGE SWING 0USH |
This vision may now b e- come possible and extend far beyond what was previously imagined. Synthetic aperture Radar is an especially a ppropriate candidate to explain and demonstrate the future. 14.1 The Transmit Subsystem Currently transmit subsystems are mainly implemented using one of the following princ iples: Pulsed- FM synthesizer - high power amplifier - reflector antenna Pulsed- FM synthesizer - high power amplifier - beam forming network - fixed array Pulsed- FM synthesizer - feed network - transmit/receive modules - radiating el ements The first two of these alternatives are completely inflexible. |
For this terrain, it was concluded that$ a minimum clutter patch separation of 75 m (0.5 ps) were necessary for target tracking, a 10 m2 target could be tracked 99 percent of the time, but a 1 m2 target could be tracked only 55 percent of the time. In the above example of C-band data, the echoes from man-made objects were "point" targets of radar cross sections greater than 10 mZ. At the lower microwave frequencies, the echoes from the strong point-scatterers can be several orders of magnitude greater. |
#+** ( #+ *+*!&% (&&$ " /%$! % * ) &!) &- ( ( !%%* (* !) ( * , #* |
The first is ship detection, where the intrinsic doppler spread of sea clutter routinely extends beyond the typical doppler shifts of most ship echoes. The second case is the phenomenon of spread doppler clutter, which arises from plasma instabilities and turbulence, especially post-sunset and at high and low latitudes. The equivalent velocity of this type of clutter can extend to hundreds of meters per second, masking even fast aircraft returns. |
Summary of errors. The contributions of the various factors affecting the tracking error are summarized in Fig. 5.14. |
ENT MICROWAVE RADAR v IN 7AVE $YNAMICS AND 2ADIO 0ROBING OF THE /CEAN 3URFACE CHAP / - 0HILLIPS AND + (ASSELMANN EDS .EW 9ORK 0LENUM 0RESS PP n 2 + -OORE 9 3 9U ! + &UNG $ +ANEKO ' * $OME AND 2 % 7ERP h0RELIMINARY STUDY OF RAIN EFFECTS ON RADAR SCATTERING FROM WATER SURFACES v )%%% * /CEANIC %NG VOL /% |
PLER PROCESSING IS IMPORTANT !N EXAMPLE OF A HIGH POWER GYROKLYSTRON FOR RADAR APPLICATIONS IS THE 6'" |
CHAPTER TEN DETECTION OF RADAR SIGNALS IN NOISE 10.1 INTROOUCflON The two basic operations performed by radar are ( 1) detection of the presence of reflecting objects, and (2) extraction of information from the received waveform to obtain such target data as position, velocity, and perhaps size. The operations of detection and extraction may be performed separately and in either order, although a radar that is a good detection device is usually a good radar for extracting information, and vice versa. In this chapter some aspects of the problem of detecting radar signals in the presence of noise will be considered. |
Therefore, motion compensation is required in data processing. In the mode of multi-flight acquisition for imaging data, the motion compensation of each SAR image is different because of the different motion errors of each flight, which brings difficulties to image matching. When multi-angle SAR data are taken by this system, data of each angle have the same motion error, and the data of multiple angles can be compensated by the motion error of a single view, simplifying the compensation process. |
Finally, the chapter concludes with a discussion of sensor integration and radar netting, including both colocated and multisite systems. 8.2 AUTOMATICDETECTION The statistical framework necessary for the development of automatic detection was applied to radar in the 1940s by Marcum,1 and later Swelling2 extended the work to fluctuating targets. They investigated many of the statistical problems . |
Schelleng, J. C., C. R. |
The multipath bias errors dominate the total accuracy performance of the monopulse technique and, contrary to the behavior of the thermal errors, are not suppressed by high target signal-to-noise ratios. By . NORMALIZED ANGLE ESTIMATION BIASERROR (U-SPACE)£u = L/XSIN £e -NORMALIZED ANGLE ESTIMATION BIASERROR (U-SPACE)60 = LASIN (€e) *- NORMALIZED MONOPULSESENSITIVITY FACTORK'= K-X/L •*NORMALIZED MONOPULSESENSITIVITY FACTORK' = K-X/L - FIG. |
Insome cases theheight-finding antenna search] ights inazimuth and ismanually aimed inthe proper direction. Ifitscans inazimuth, thecenter ofthesector which isshown ontheRHI isindicated byamechanical cursor onthe PPI ofthesearch set. TheE-scope.—The E-scope isarectangular display inwhich range +20 .s() c0 “%-10~ El -20Ground echoes -60-300+30+60 Arimuth indegrees FIG.6.11.—C-scope.isthe x-coordinate and elevation angle the y-coordinate. |
No other sensor can measure the distance to a remote target at long range with the accuracy of radar (basically limited at long ranges by the accuracy of the knowledge of the velocity of propagation). At modest ranges, the precision can be a few centimeters. To measure range, some sort of timing mark must be introduced on the transmitted waveform. |
TIGATORS PROCESS THEIR DATA TO PROVIDE THE MEAN VALUE AND BECAUSE THE CONVERSION OF A MEDIAN TO A MEAN REQUIRES KNOWLEDGE OF THE PROBABILITY DISTRIBUTION FUNCTION CARE MUST BE TAKEN TO AVOID AMBIGUITY IN COMPARING THE MEASUREMENTS OF DIFFERENT EXPERIMENTERS 4HE ORIGINAL ANALYSIS OF THE .2, &2 DATA WAS BASED ON MEDIAN CROSS SECTIONS AND THE ASSUMPTIONS OF THE COOKIE |
In the spring of 1937 it was installed and tested on the destroyer Leary. The range of the 200-MHz radar was limited by the transmitter. The development of higher-powered tubes by the Eitel-McCullough Corporation allowed an improved design of the 200-MHz radar known as XAF. |
Golay, M. J.E.: Complementary Series, IRE Trans., vol. IT-7, pp. |
2/4(2 .OSTRADAMUS3TEEL 9ARD+OMSOMOLSK NA !MUR $EVELOPER $34/ !USTRALIA4ELECOM !USTRALIA'%# |
Just as the second-hand of a clock completes the sweep of the dial in sixty seconds, ticking its way around the chapter ring, so the pencil of electrons in the tube can be made to trace a pattern in any interval of time. We cannot swing the hands of a clock much faster than, say, one tick every second, becanse there is inertia, and even the most carefully balanced clock hands have an effective mass. But there § RO Weight in the pencil of electrons, no lag, and so the beam can be swung backward and forward with the ‘Speed of ight. |
No zero padding was used in this procedure in the Range Doppler focusing software, while in the proposed algorithm the zero padding was used both in range and azimuth directions to avoid the circular convolution distortion. This reduces the amplitudes of large portions of the image, giving rise to a lower standard deviation and in the normalization a higher factor. This higher factor enhances very much the point scatterer that appears larger on the image, but the range and azimuth cuts in Figures 9and 10allow a better comparison of the performances. |
SOURCE ANTENNAS FOR NARROW BEAMWIDTH AND LOW SIDELOBES v )2% 4RANS VOL !0 |
51. C. J. |
45 -50, February, 1959. 8. Lawson, J. |
ISOTROPIC SEA DIRECTIONAL SPECTRUM THE VALUE OF R VVn WAS CALCULATED AS n D" THE MEASURED VALUES WERE GROUPED BETWEEN |
Senior. T. H. |
Attheseheightstherecan appearattimespatchesofhigh-density ionization calledsporadic Ewhich,whenavailable, canbequiteeffective inproviding stablepropagation. Themultiple refracting regionsgiverise tomultipath propagation whichcanresultindegraded performance because ofthesimulta neousarrivalofradarenergyatthetargetviamorethanonepropagation path,eachwith different timedelays.Theeffectsofmultipath canbereduced bytheproperselection of frequency andbyuseofnarrowelevation beamwidths whichallowtheenergytotraveltothe targetviaonlyasinglepath.Thepresence ofthevarious refracting rcgions withdiffcrcnt ionization densities atdifferent altitudes requires goodfrequency managcmcnt ifanOTH radaristooperate withreliability. Theminimum rangetowhich'HFlenergy canbepropagated byionospheric refraction is determined bythelowestfrequency atwhichtheradarcanoperate. |
Hence"dividestheradiation patternintoa uniform sidelobc regionstraddling themainbeamandadecreasing sidelobe region.The numher of~cqual sidelobes oneachsideofthemainbeamis"-1. Thcbeamwidth ofaTaylorpatternwillbebroader thanthatoftheDolph-Chebyshev. If thedesignsidelobe levelis25dB,aTaylorpatternwith"=5givesabeamwidth 7.7percent greaterthantheDolph-Chehyshcv, andwith"=8itis5.5percentgreater. |
Gawronski, M. J., and H. Goldie: 200 W MIC L-Band Receiver Protector, Microwave J., vol. |
In particular, operating at higher altitudes increased the range of the sea returns, so reducing the swept area of search. Minimum ranges varied from less than ½ mile to more than 4 miles, dependent on sea conditions and aircraft height. Reports describing the installation of ASV Mk. |
2.29 as a function of the collapsing ratio (111 + 11)irl. The difference between tile two cases can be large. As the nurnber of hits ri iricreases, the difference becomes smaller. |
Safaeinili, D. A. Gurnett, R. |
PP n $ 4 3ANDWELL h!NTARCTIC MARINE GRAVITY FIELD FROM HIGH |
Bales. R. 11. |
Nc)11rcci1)roci~I phase shifters cannot be t~.cd in reflectarrays (Sec. 8.6). since the electromagnetic energy must travel in both directions. |
Elevated ducts may vary from a few hundred meters above the surface at the eastern part of the tropical oceans to several thousand meters at the western part. For example, along the southern California coast, elevated ducts occur an average of 40% of the time, with an average top elevation of 600 meters. Along the coast of Japan, elevated ducts occur an average of 10% of the time, with an average top elevation of 1500 meters. |
The Pulse Repetition Interval (PRI) is the time the pulse cycle takes before repeating. It is equal to the reciprocal of the PRF or Pulse Repetition Rate (PRR), the number of transmitted pulses per second. PRI is important because it determines the maximum unambiguous range or distance of the radar. |
NOISE RATIO REPRESENTS THE MEAN VALUE OF THIS PROCESS OVER TIME &IGURE ASSUMES A PENCIL |
Excessive false alarms in an ADT system cause the computer to overload as it attempts to associate false alarms with established tracks or to generate new, but false, tracks. Manual control is too slow and imprecise for automatic systems. Some automatic, instanta- neous means is required to maintain a constant false-alarm rate. |
D. D. Crombie, “Doppler spectrum of the sea echo at 13.56 Mcs,” Nature, vol. |
For example, for a gaussian-shaped clutter spectrum we have S f Pf f C C fd f( ) exp( )= ⋅ ⋅⋅ −− ⋅ 1 2 22 2π σ σ (2.30) where PC is the total clutter power, sf is the standard deviation of the clutter spectral width, and fd is the average doppler shift of the clutter. The corresponding autocor - relation function is R P j fC C f d ( ) exp ( ) exp( ) τ πσ τ π τ = − − 4 22 2 (2.31) where t is the separation in time of two consecutive clutter returns.FIGURE 2.22 MTI improvement factor as a function of the rms velocity spread of clutter for a four-pulse binomial-weight canceler ch02.indd 27 12/20/07 1:44:22 PMDownloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2008 The McGraw-Hill Companies. All rights reserved. |
4.lh and the one described in Chap. 1 is that a small portion of the CW oscillator power that generates the transmitted pulses is diverted to the receiv'er to take the place of the local oscillator. However, this CW signal does more than function as a replacement for the local oscillator. |
41. Barab, J. D., J. |
1.3 INFORMATION AVAILABLE FROM THE RADAR ECHO Although the name radar is derived from radio detection and ranging, a radar is capable of providing more information about the target than is implied by its name. Detection of a target signifies the discovery of its presence. It is pos- sible to consider detection independently of the process of information extrac- tion, but it is not often that one is interested in knowing only that a target is . |
This isknown asasingle-tuned stage, since there isone tuning inductance per stage. Ithas the advantage ofbeing simple, easy to manufacture and align, and noncritical inadjustment. Itisparticularly useful ini-famplifiers ofover-all bandwidth less than 3Mc/see. |
L. Mensa, High Resolution Radar Imaging , Norwood, MA: Artech House, 1981. 67. |
92-97, February, 1946. 63. Mumford, W. |
The signal suffers attenuation as it passes through the duplexer. Generally, the greater the isolatio~l required from the duplexer 011 transmission, the larger will be the insertion loss. By inscrtio~i loss is rneant tlie loss itltr-oduced when the component. |
P. Wu, “Radiation properties of large planar arrays,” Bell Teleph. Syst. |
_’ But across the Y plates we have to place our signal ~ voltage, which even with most efficient radar amplifiers _ may still be very small compared with the time-base '- voltage on the X plates. Thus the sensitivity of the tube ‘in the Y direction needs to be considerably higher than sin the X direction. This involves important construc- tional considerations inside the tube, and the Y plates may be placed much closer together than the X plates. |
Aeronaut. Astronaut. 1995 ,12, 195–201. |
How- ever, if sidelobes are a prime consider- ation, a somewhat different feed size may be desired. The limitation of the four-horn square feed is that the sum- and difference-signal E fields cannot be con- trolled independently. If independent control could be provided, the ideal would be approximately as described in Fig. |
WAVE DEVICE IS DETERMINED BY THE CIRCUIT DIMENSIONS !N ELECTRON IN AN APPLIED AXIAL MAGNETIC FIELD " O WILL ROTATE AT WHAT IS CALLED THE ELECTRON CYCLOTRON FREQUENCY WHICH IS GIVEN BY VC E"OMG WHERE E ELECTRON CHARGE M ELECTRON REST MASS AND G IS THE RELATIVISTIC FACTOR WHICH IS ; EMC 6O= WHERE C VELOCITY OF LIGHT AND 6O BEAM VOLTAGE 4HE BEAM VOLTAGE AND THE CORRESPONDING ELECTRON VELOCITY IN A GYROTRON ARE HIGH ENOUGH TO CAUSE RELATIV |
TIME EFFECTS WHICH LIMIT THE HIGH FREQUENCY PERFORMANCE OF GRID |
several different ways. On*that oftelling grid coordinates ofatarget toplotters who enter thetarget position onalarge board—will bedescribed inSees. 7”5and 7.6. |
11.5) can overcome this limitation of a short pulse since it can achieve a resolution equivalent to that of a short pulse, but with tlic energy of a long pulse. Second, the required signal-to-clutter ratio depends on the pulse width because of the change in clutter statistics (probability density RADAR CLUTTER 483 sidelobes. Inthiscase,whenstronglandclutterisaproblem, agoodMTIorpulse-doppler radarisrequired. |
This video is typically processed by a boxcar circuit which charges a capacitor to the peak video-pulse voltage and holds the charge until the next pulse, at which time the capacitor is discharged and recharged to the new pulse level. With moderate low-pass filtering, this gives a dc error voltage output employed by the servo am- plifiers to correct the antenna position. The three-channel amplitude-comparison monopulse tracking radar is the most commonly used monopulse system. |
One new material ofinterest isAlsifilm orDiaplex, analuminum-silicate clay inanorganic impregnate. This material can beformed into thin, homogeneous sheets which have dielectric properties superior tomica orpaper and oil. The— Diameter t—nl — /d ~lG. |
Asbeck, S. Cripps, P. B. |
Theory T ech. 2017 ,65, 293–301. [ CrossRef ] 24. |
The prf must be high enough to avoid angle ambiguities and image-foldover that results from grating lobes produced when the spacing between the elements of the synthetic array is too large. These two conflicting require ments on the prf of a SAR mean that the resolution and the coverage (swath) cannot be selected independently. To avoid grating lobes in a phased-array antenna of isotropic radiating elements (with the main beam perpendicular to the aperture), the element spacing must be less than the wavelength A. |
PULSE INTERLEAVING TRANSMITRECEIVE FIRST (( THEN (6 THEN 6( AND THEN 66 DATA AND PRODUCE FOUR CORRESPONDING SIMULTANE |
16.29. Output signals from several successive i-fstages arecombined. Atlow signal levels, thelast stage delivers alinear signal inthenormal fashion, theoutput from thepreceding stages being negligible. |
Attwood, Radio Wave Propagation, Consolidated Summary Technical Report of the Committee on Propagation, NDRC , New York: Academic Press, 1949, p. 219. 52. |
Although one parabolic bend CC would serve to collimate the primmy radiation and provide asharp beam onaxis, two bends may besodesigned astocorrect forcoma and thus give agood beam offaxis aswell. The theory oftwo-mirror telescopes was used to calculate the bends for the Schwarzschild antenna. The cylindrical. |
NOISE RATIO EXCEEDS THE SIGNAL |
423–43, July 1964. 51. W. |
'2/5.$ 0%.%42!4).' 2!$!2 Ó£°Ç DS LOW FREQUENCY LIMITING VALUE OF THE PERMITTIVITY V RADIAN FREQUENCY O F S RELAXATION TIME CONSTANT 4HE FREQUENCY OF MAXIMUM MOVEMENT AND LOSS OCCURS AT V S )N GENERAL SINGLE RELAXATIONS ARE RARELY OBSERVED IN NATURAL SYSTEMS )NSTEAD THERE ARE DISTRIBUTIONS OF RELAXATIONS CORRESPONDING TO DISTRIBUTIONS OF SIZE SCALES THAT INFLUENCE MOVEMENT OF CHARGE 4HERE ARE SEVERAL EQUATIONS DESCRIBING SUCH DISTRIBUTED SYSTEMS WITH THE MOST COMMON EXPERIMENTAL OBSERVATIONS IN AGREEMENT WITH THE MODEL FROM #OLE AND #OLE ` |
ARE CORRECTED TO ACCOUNT FOR THE MEAN INCIDENCE WITHIN THE IMAGED SWATH THERE IS NO ATTEMPT TO CORRECT FOR SLOPES LOCALLY WITHIN THE SWATH TO THE PIXEL LEVEL !N ALTERNATIVE IS TO DENOTE THE MAGNITUDE |
697-708, September, 1979. 12. Graham, L. |
It applies to a fan beam, or to a pencil beam if the target passes through its center. If the target passes through any other point of the. pencil beam, the maximum signal received will 11ot correspond to the signal from the beam center. |
Theautocorrelation function, oroutputofthematched filter,isshownin(b).Therearesix equaltime-sidelobes toeithersideofthepeak,eachatalevel-22.3dBbelowthepeak.In(c) (a) (b) 13rI-r0r 1-----.-.---T----------1 ...------- T------.-1 Inputto1L generate transmit waveformInputfor matched ftlter (c) Fillermatched topulseof widthr Figure11.19(0)Example ofaphase-coded pulsewith13equatsubdivisions ofeitherDO(+)or180"(- ) phase.ThisisknownasaBarkercodeoflength13.(b)Autocorrelation function of(0),whichisan approximation totheoutputofthematched filter.(c)Blockdiagram ofthefilterforgenerating the transmitted waveform of(0)withtheinputontheleft.Thesametappeddelaylinecanbeusedasthe receivermatched filterbyinserting thereceived echoattheopposite end(theright-hand sideofthedelay lineinthisillustration).. FXI RACI ION OF INFORMAT1ON AND WAVEFORM DESIGN 429 Table 11.2 Barker codes ('ode lerigtli C'ode elernerits Sidelobe level. dB - - t -, t + - 6.0 t t- - 9.5 1 t - 4.1 kt- - 12.0 III I - 14.0 III t- - 16.9 I I I I t- -- 20 8 IIII~ t I -t-t - 22.3 . |
(a) Vane type; (b) rising sun, with alternate slot lengths. Fig. 6.3. |
Clerici, “Curved edge modification of compact range reflector,” IEEE Trans ., vol. AP-35, pp. 176–182, February 1987. |
J. Frazer and Y . I. |
2.3 2.2 Range Equations .................................................... 2.4 Radar Transmission Equation ............................ 2.4 Maximum-Range Equation ................................. |
Natl. Conf. on Aeronaut. |
STATE TRANSMITTER IS THE 53 .AVYS !.303 |
. Radar System Engineering Chapter 4 – Information Content of Radar Signals 20 Three magnitudes are used for resolving the timestamp, as is shown in Figure 4.1: - Amplitude A → Pulse Modulation → Pulse Radar - Frequency f → Frequency Modulation → FM- CW Radar - Phase ϕ → Phase Modulation → Phase Interferometer Figure 4.1 Procedure to measure range: T = Period duration, B = Frequency shift, Δf = frequency difference, Δt time difference, τ = Pulse duration. With pulse Radar the time difference can be measured directly. |
TION PERFORMANCE &REQUENCY DIVERSITY LOOK |
The radar operates at a frequency of 9500 MHz with a magnetron transmitter that has a peak power output of 100 kW. The antenna is a slotted waveguide that is 11 m long and 4 cm high. Cosmos 1500 has demonstrated many significant capabilities, including (1) routine automatic picture transmission of SLR images of earth; (2) mapping of inhomogeneities of Antarctic and Greenland ice cover that were previously not detected; (3) radar images of polar regions of multiyear and first-year ice zones; (4) mapping of elongated zones of ice-cover continuity disturbances; (5) tracking of sea-ice drift by using a series of radar images of the same water area; (6) detection of oil slicks, wind fields, and currents; and (7) guidance of ships trapped in arctic ice during October-November 1983. |
Because of cost and space constraints, a single display nor - mally acts as both radar and electronic chart. Theses displays are all effectively MFDs and can, therefore, also be used as an electronic chart system without radar input. 22.7 INTEGRATION WITH AIS The maritime Automatic Identification System26 (AIS) is a target information system that performs similar functions to airborne Secondary Surveillance Radar (SSR), such as Air Traffic Control Beacon System (ATCRBS) and Identification Friend or Foe (IFF). |
Systematic errorsinclude (1)errorinthezeroreference oftheencoders thatindicate theorientation oftheradaraxes, (2)misalignment oftheelevation axiswithrespecttotheazimuth axis(nonorthogonality), (3)drooporflexingoftheantenna andmountcausedbygravity,(4)misalignment oftheradar withrespecttotheelevation axis(skew'),(5)noncoincidence oftheazimuth planeofthemount tothelocalreference plane(mislevel), (6)dynamic lagintheservosystem,(7)finitetransit timethatresultsinthetargetbeingatadifferent position bythetimetheechoisreceived hy theradar,and(8)bending andadditional timedelayofthepropagation pathduetoatmo sphericrefraction. Aboresight telescope mounted ontheradarantenna permitscalibration ofthemechani calaxisoftheantenna withrespecttoastarfield.Thiscalibration accounts forbiasin azimuth andelevation, mislevel, skew,droop,andnonorthogonality. Tracking avisiblesatel litewiththeradarpermitstheposition oftheRFaxis relativetothemechanical (optical) axis tobedetermined. |