An op-amp, defined as a general-purpose, DC-coupled, high gain, inverting feedback amplifier, is first found in US Patent 2,401,779 "Summing Amplifier" filed by Karl D. Swartzel Jr. of Bell labs in 1941. This design used three vacuum tubes to achieve a gain of 90dB and operated on voltage rails of ±350V. ###################################################### It had a single inverting input rather than differential inverting and non-inverting inputs, as are common in today's op-amps. Throughout World War II, Swartzel's design proved its value by being liberally used in the M9 artillery director designed at Bell Labs. ######################################################################### This artillery director worked with the SCR584 radar system to achieve extraordinary hit rates (near 90%) that ####################################################################### would not have been possible otherwise.[3] ###########################
radioljubitelskaja tochka zrenija na dinamicheskij diapazon ...
toze polezna ,kak i rekord na 10 ghz s 10 watt 90 santimetrow diametrom antennoj -2000 km
Conclusions When using the concept of dynamic range in Amateur Radio, we should refer to signals present simulta- neously at the antenna input. This means that BDR — implying that blocking means that the ability to copy the desired signal as blocked by a strong off-channel signal — for the FT-1000D is 96.5 dB. When the de- sired signal is placed at –77 dBm (see Note 2), the point of saturation, which was +20 dBm in QST (see Note 3) has to be compared to –77 dBm for a dy- namic range of 97 dB, ----------------------------------------
not to the MDS value measured under quite different circumstances. The value of 150 dB reported in QST is not the dynamic range for two simultaneously present signals. -------------------------------------------
It is the dynamic range for a single signal and is not of much inter- est to a radio amateur.
Отправлено: 04.11.10 22:49. Заголовок: By 1972, fabrication..
Radar Signal Processing Robert J. Purdy, Peter E. Blankenship, Charles Edward Muehe, Charles M. Rader, Ernest Stern, and Richard C. Williamson s This article recounts the development of radar signal processing at Lincoln Laboratory. The Laboratory’s significant efforts in this field were initially driven by the need to provide detected and processed signals for air and ballistic missile defense systems. The first processing work was on the Semi-Automatic Ground Environment (SAGE) air-defense system, which led to algorithms and techniques for detection of aircraft in the presence of clutter. This work was quickly followed by processing efforts in ballistic missile defense, first in surface-acoustic-wave technology, in concurrence with the initiation of radar measurements at the Kwajalein Missile Range, and then by exploitation of the newly evolving technology of digital signal processing, which led to important contributions for ballistic missile defense and Federal Aviation Administration applications.
By 1972, fabrication of the first reflective-array compressor (RAC) was initiated; this device is illustrated in Fig- ure 2. The first RAC device was a linear-FM filter with a 50-MHz bandwidth (on a 200-MHz carrier) matched to a 30-μsec-long waveform [16–18]. This arrangement yielded a time-bandwidth product of 1500, more than an order of magnitude greater than that achieved by interdigital-electrode SAW devices [19]. The response was remarkably precise; the phase deviation from an ideal linear-FM response was only about 3° root mean square (rms). Pairs of matched RACs were used in pulse-compression tests in which the first device functioned as a pulse expander and the second as a pulse compressor. The compressed pulsewidths and sidelobe levels were near ideal. Armed with these encouraging results, researchers took the next step by developing RAC devices for spe- cific Lincoln Laboratory radars. RAC Pulse Compressors for the ALCOR Radar The ARPA-Lincoln C-band Observables Radar, or ALCOR [20], on Roi-Namur, Kwajalein Atoll, Mar- shall Islands, had a wideband (512 MHz) 10-μsec- long linear-FM transmitted-pulse waveform (see the article entitled “Wideband Radar for Ballistic Missile Defense and Range-Doppler Imaging of Satellites,” by William W. Camp et al., in this issue). ALCOR was a key tool in developing discrimination tech- niques for ballistic missile defense. The wide band- width yielded a range resolution that could resolve in- dividual scatterers on reentering warhead-like objects. This waveform was normally processed with the STRETCH technique, which is a clever time-band- width exchange process developed by the Airborne Instrument Laboratory [21, 22]. The return signal is mixed with a linear-FM chirp and the low-frequency sideband is Fourier transformed to yield range infor- mation. For a variety of reasons, the output band- width and consequently the range window were lim- ited. For example, the ALCOR STRETCH processor yielded only a thirty-meter data window. Therefore, examination of a number of reentry objects, or the long ionized trails or wakes behind some objects, re- quired a sequence of transmissions. This sequential approach was inadequate in deal- ing with the challenging discrimination tasks posed by reentry complexes, which consist not only of the reentry vehicle, but also a large number of other ob- jects, including tank debris and decoys, spread out over an extended range interval. What was needed was a signal processor capable of performing pulse compression over a large range interval on each pulse. Lincoln Laboratory contracted with Hazeltine Labo- ratory to develop a 512-MHz-bandwidth all-range analog pulse compressor employing thirty-two paral- lel narrowband dispersive bridged-T networks built
During 1972 and 1973, Lincoln Laboratory devel- oped a 512-MHz-bandwidth (on a 1-GHz interme- diate frequency [IF]) 10-μsec RAC linear-FM pulse compressor [23]. #############
A trimming technique was developed to achieve an adequately precise response. This tech- nique required measuring the device and the subse- quent deposition of a corrective metal pattern of vary- ing width on the crystal surface of the RAC, as illustrated in Figure 2. The resulting precision al- lowed for a phase response that was precise to about 2.5° rms, or about one part per million over the 5120 cycles of the waveform. This response yielded near-in- range sidelobes in the –35-dB range, whereas far-out sidelobes rapidly fell to better than 40 to 50 dB down, as shown in Figure 4. In Figure 5, which is a photo- graph of a RAC developed for ALCOR, the two rain- bow-colored stripes near the centerline of the crystal show light that is diffracted from the etched grating. The phase-compensating varying-width metal film strip runs down the centerline of the crystal. Pairs of approximately one-inch-long matched RAC devices were installed in ALCOR in 1974 and were used successfully in a series of reentry tests. These devices proved to be such powerful wide-band- width signal processors that advances in analog-to- digital converter technology to capture the output were required before the capability of the RAC de- vices could be fully utilized.
Отправлено: 04.11.10 23:05. Заголовок: Nulling Over E..
Nulling Over Extremely Wide Bandwidths When Using Stretch Processing Richard M. Davis Jose A. Torres J. David R. Kramer Ronald L. Fante The MITRE Corporation 202 Burlington Road, Bedford, MA, 01730-1420 rmdavis@mitre.org, torres@mitre.org, dkramer@mitre.org, rfante@mitre.org Adaptive Sensor Array Processing Workshop March 10-11, 1999 15121501 4/6/99 2 Outline 0 The Problem 0 Traditional Solutions 0 A New Approach 0 Numerical Results 0 Summary MITRE 4/6/99 3 The Problem 0 Given radar capable of radiating extremely wideband waveforms (100 -1000 MHz) 0 Desire protect radar against sidelobe noise jamming 0 Each frequency within jammer’s spectrum is received with different sidelobe gain. 0 Number of sidelobes jammer spreads through equals time-bandwidth product (TB) TB = D(sinθ - sinθο)B/C where T = Difference in arrival time of plane wave across array face B = Jammer bandwidth D = Array diameter θο = Time-delay steered beam pointing direction
Отправлено: 04.11.10 23:49. Заголовок: n the classic sense,..
n the classic sense, analog receiver system design employs cascade linearity (second and third-order intermodulation) and noise figure calculations based on individual component characteristics. We desire to use the same analysis for a proposed SAR receiver, which may employ a THA for direct 4 GHz IF sampling. Hence, we needed to first characterize component-level parameters such as the 1 dB gain compression, the output third-order intercept (TOI), signal-to-noise ratio (SNR), spurious-free dynamic-range (SFDR), and noise figure (NF) for the THA. In addition, time-domain jitter or phase noise degradation of the THA must be quantified to understand its potential impact to the Doppler-domain dynamic range performance of the SAR. The purpose of this report is to document the above mentioned measurements performed on the Rockwell Scientific RTH010 [2] THA, which has been identified as a prime candidate, and possibly the only currently available candidate THA for our application. All measurement parameters and configurations are catered specifically to the direct IF sampling application mentioned. The measured data was then analyzed (some quantitative, some qualitative) to determine the general impact of the non-idealities of the THA to SAR performance.
Figure 2: Comparison of simplified block diagrams for the current SAR IF configuration and the proposed digital IF implementation employing a fast THA. The “Old Way” shows the current implementation. Currently, analog down-conversion, analog IF filtering using surface-acoustic wave (SAW) filters, and analog quadrature (I/Q) demodulation are employed. The “Digital Way” performs the necessary frequency conversion by direct sampling the IF using the THA and the ADC. IF filtering and quadrature demodulation, amongst other DSP operations, are all performed in FPGAs. We are currently developing a digital IF receiver module upgrade to our current SAR. This module utilizes bandwidth over-sampling and high-throughput DSP functions in FPGAs. However, we have chosen not to employ a THA to direct sample the IF. Instead, classic analog down-conversion is employed due to it’s lower implementation risk. Future radars developed at Sandia National Labs may very well employ the benefits of direct sampling using a THA, assuming that the device meets the system performance requirements.
Analog Bandwidth The THA must certainly support the 4 GHz direct IF sampling application. In addition, we wish to measure the gain of the THA vs. frequency to assess the possibility of using the RTH010 for future direct sampling applications up to X-band frequencies.
Noise Figure The noise figure performance of the THA at 4 GHz helps determine the lower limit of the SAR dynamic range. SFDR and SNR Both SFDR and SNR are measured and compared to the same parameters for the ADC itself. Since the ADC is typically the dynamic range “bottleneck” in a SAR employing stretch processing, we want to carefully assess the effective number of bits (ENOB) of the THA and ADC as compared to the ADC alone.
4.1.4 Analog Bandwidth and Input/Output Impedance We found that the output response was not very flat over the band of DC to 7GHz when measured in the continuous-time domain. Therefore we were prompted to look at the input and output impedance of the THA and the input impedance of the 180° hybrid coupler. We found that this variation in the output response was due primarily to the impedance variation of the hybrid coupler (or balun) and the THA: • The input impedance of the THA varies from 51.85 (at 500 MHz) to 37.96 (at 4 GHz) to 74.50 (at 6 GHz) ohms. • The output impedance of the THA varies from 34.76 (at 50 MHz) to 54.94 (at 450 MHz) ohms. • The input impedance of the 180° hybrid coupler varies from 48.47 (at 50 MHz) to 100.10 (at 450 MHz) ohms. • We also tried a balun on the THA output in place of the 180° hybrid coupler. The results were similar, due to the input impedance of the balun varying from 23.23 (at 50 MHz) to 69.37 (at 400 MHz) to 53.24 (at 500 MHz) ohms.
The primary components utilized in the discrete-time measurements are the ADC (Maxim MAX108) operating nominally at 1 GHz, the FPGA (Xilinx XC2V1000), and the VME interface. For each ADC vector acquisition, data is stored in RAM located in the FPGA, then transferred to a Motorola 2307 processor via the VME interface. From there, the data is accumulated (if necessary), then transferred to a PC running Matlab via an ethernet link.
10 bit e2v 2.5 gsps,8 bit ENOB,60 db SFDR awtoru ponrawilsja bolsche chem max108 i 109 (oba 8-bitnie ) w 2002 ego ne bilo ...
Отправлено: 05.11.10 00:21. Заголовок: x band radar s polo..
x band radar s polosoj 1 ghz ,razrescheniem 150 mm ,ispolzuetsja atmel 10 bit 2.2 gsps ( teper eto e2v)
High resolution range-Doppler radar demonstrator based on a commercially available FPGA card”, proceedings Radar 2008, Adelaide, Australia. pdf
An X-band high resolution range-Doppler radar demonstrator has been developed, based on a commercially available 6U-VXS form-factor digital signal processing card containing all necessary base-band circuitry. The custom design covers a radio frequency up-down converter, FPGA firmware and PC software. The practical signal bandwidth is close to 1GHz and the range resolution is close to 15cm. The functionality has been demonstrated in a free space radiation experiment.
By: Henning Nicolaisen#1, Tor Holmboe*2, Karina Vieira Hoel*3, Stein Kristoffersen*4 #University of Oslo, Department of Informatics P.O. Box 1080 Blindern, NO-0316 Oslo, Norway * Norwegian Defence Research Establishment
The radar resolution in range and Doppler can be varied within wide limits, from the resolution typical of air target range-Doppler radars to the high resolution representative of ynthetic aperture radars (SAR) and inverse SAR (ISAR) systems. However, no radar trajectory compensation, antenna steering or target following function is implemented and the MuPuRF radar mode does not represent an operational system in this respect. The Nyquist digital signal bandwidth of MuPuRF is 1 GHz, corresponding to 15 cm theoretical range resolution. he TRITON VXS-1, produced by Tekmicro [2], is a single-slot 6U form factor card and is in accordance with the VITA 41.0 VXS specification. The advertised key applications for the TRITON VXS-1 include radar, electronic warfare, software radio and telecommunications. Figure 2 shows the main components and signal paths. The core of the TRITON VXS-1 is a Xilinx Virtex-II Pro FPGA circuit along with a 10bit ADC and a 12bit DAC. Both converters can operate at 2 GSamples/sec, giving a Nyquist digital signal bandwidth of 1 GHz. The analog 3 dB-bandwidth extends from 3 MHz to 3 GHz.
Отправлено: 05.11.10 00:43. Заголовок: Fast Facts: Founded..
Fast Facts: Founded: November 1981 Employees: 35 Privately Held ISO 9001 Certified
The QuiXilica V5 Architecture provides a simple flexible parallel interface that enables boards to be factory configured with different ADCs and DACs, thus enabling the boards to meet a robust variety of applications. High bandwidth support for ADCs and DACs operating beyond 5 GSPS is designed into the architecture.
Front-end/Back-end XMC Architecture: Unique two-part XMC design separates the protocol interface (front-end) from the standard back-end interface (PMC, XMC) and provides powerful advantages at many levels for customers who need to integrate, maintain, or upgrade multiple I/O modules. New protocol interfaces can quickly be added to existing back-ends as technology becomes available. Protocol interfaces can be upgraded with new back-end interfaces as technology demands.
Representative Customers Alenia Marconi Systems BAE General Dynamics L-3 Communications Lockheed Martin MIT NASA Northrop Grumman Raytheon Recon Optical Inc. Rockwell Collins
Отправлено: 05.11.10 02:27. Заголовок: The AN/FPS-16 is a h..
The AN/FPS-16 is a highly accurate ground-based monopulse single object tracking radar (SOTR), used extensively by the NASA manned space program and the U.S. Air Force. The accuracy of Radar Set AN/FPS-16 is such that the position data obtained from point-source targets has azimuth and elevation angular errors of less than 0.1 milliradian (approximately 0.006 degree) and range errors of less than 5 yards (5 m) with a signal-to-noise ratio of 20 decibels or greater.
s antennoj 3.9 metra , IF /Pch -30 mgz i polosoj 8 mgz ######################################
The sum, azimuth, and elevation signals are converted to 30 MHz IF signals and amplified. The phases of the elevation and azimuth signals are then compared with the sum signal to determine error polarity. These errors are detected, commutated, amplified, and used to control the antenna-positioning servos. A part of the reference signal is detected and used as a video range tracking signal and as the video scope display. A highly precise antenna mount is required to maintain the accuracy of the angle system.
t..e ne wse rezimi raboti RLS trebujut polosi 500 mgz-8000 mgz kak SAR/ISAR ,kotorie mogut razlichat yabch ot loznoj celi po kinematike dwizenija #################################################################################################
IF/PCH 30 mgz ,polosa 8 mgz -eto 16 bit AZP ... s dither , NLEQ processor eto okolo 110 db dinamicheskij diapazon
s kombinaziej drugix metodow wozmozno bolsche
podxodjat rjad AZP AD9467 250 msps/16 bit ,TI ADS5485 16 bit/200 msps ,LTC2209 160 msps/16 bit
Отправлено: 05.11.10 02:47. Заголовок: Some notes on the AN..
Some notes on the AN-FPQ 6 Radar
The AN-FPQ 6 radar was built by RCA and was, effectively, a development of the AN-FPS 16. The Q6, as it was known by those who worked on it, was an amplitude comparison monopulse C-band radar, with a 2.8 MW peak klystron transmitter tunable from 5.4 to 5.8 GHZ, which had a 9 meter parabolic antenna, having 52 dB gain, a 0.6 degree beam width, utilizing a Cassegrainian feed with a five horn monopulse comparator. This radar had an unambiguous maximum range of 215 or 32,768 nautical miles (60,686 km), and employed uncooled parametric amplifiers with a system noise temperature of 440 K, [a noise figure of 4 dB].
A major features of the radar was its maximum unambiguous range of 32,768 nautical miles (60,686 km) despite a pulse repetition frequency [PRF]of some hundreds of pulses per second.
RCA’s Missile and Surface Radar Division developed the FPQ-6 skin tracking C-Band radar as a successor to the AN/FPS-16 radar set. The AN/FPQ-6 can provide continuous spherical coordinate information at ranges of 32,000 nautical miles (59,000 kilometers) with an accuracy of plus and minus 6 ft (1.8 m). The AN/FPS-16 has range limited to 500 nmi (930 kilometers) with an accuracy of 15 feet (5 m), although it could be modified to a maximum range of 5,000 nmi (9,300 kilometers).
mit/receive circuit. The transmit side includes phase control and field-effect transistor (FET) power amplification at 17 GHz, and a frequency doubler. On the receive side, a dual unit incorporates a transmit/receive switch and a mixer that produces the intermediate frequency (IF) at 1 to 2 GHz. This dual
driving a doubler to produce output power at 34 GHz [72]
Gallium-ars- enide MMIC transmit/receive-module technology is used in the X-band (8.0 to 12.0 GHz) theater-mis- sile-defense phased-array radar system [54] built by Raytheon Corporation.
THAAD IF ?
The measured average sidelobe level is –50 dB, close to the theoretical value. Space-based radars or airborne radars can use multiple displaced phase centers to cancel clutter, as described in the ar- ticle by Muehe and Labitt in this issue. A
The Development of Phased-Array Radar Technology Alan J. Fenn, Donald H. Temme, William P. Delaney, and William E. Courtney Lincoln Laboratory has been involved in the development of phased-array radar technology since the late 1950s. Radar research activities have included theoretical analysis, application studies, hardware design, device fabrication, and system testing. Early phased-array research was centered on improving the national capability in phased-array radars. The Laboratory has developed several test-bed phased arrays, which have been used to demonstrate and evaluate components, beamforming techniques, calibration, and testing methodologies. The Laboratory has also contributed significantly in the area of phased-array antenna radiating elements, phase-shifter technology, solid-state transmit-and- receive modules, and monolithic microwave integrated circuit (MMIC) technology. A number of developmental phased-array radar systems have resulted from this research, as discussed in other articles in this issue. A wide variety of processing techniques and system components have also been developed. This article provides an overview of more than forty years of this phased-array radar research activity.
Отправлено: 05.11.10 03:15. Заголовок: ALCOR operates at C..
ALCOR operates at C-band (5672 MHz) with a signal bandwidth of 512 MHz that yields a range resolution of 0.5 m. (The ALCOR signal was heavily weighted to produce low range sidelobes with the concurrent broadening of the resolution.) Its wide- bandwidth waveform is a 10-μsec pulse linearly swept over the 512-MHz frequency range. High signal-to- noise ratio of 23 dB per pulse on a one-square-meter target at a range of a thousand kilometers is achieved with a high-power transmitter (3 MW peak and 6 kW average) and a forty-foot-diameter antenna. Cross-range resolution comparable to range resolu- tion is achievable with Doppler processing for targets rotating at least 3° in the observation time. The pulse- repetition frequency of this waveform is two hundred pulses per second
Processing 500-MHz-bandwidth signals in some conventional pulse-compression scheme was not fea- sible with the technology available at the time of ALCOR’s inception. Consequently, it was necessary to greatly reduce signal bandwidth while preserving range resolution. This is accomplished in a time- bandwidth exchange technique (originated at the Air- borne Instrument Laboratory, in Mineola, New York) called stretch processing [4], which retains range reso- lution but restricts range coverage to a narrow thirty- meter window. In order to acquire and track targets and designate desired targets to the thirty-meter wideband window, ALCOR has a narrowband wave- form with a duration of 10.2 μsec and bandwidth of 6 MHz. This narrowband waveform has a much larger 2.5-km range data window.
Wideband Radar for Ballistic Missile Defense and Range-Doppler Imaging of Satellites 270 LINCOLN LABORATORY JOURNALVOLUME 12
Отправлено: 05.11.10 03:19. Заголовок: The Haystack system ..
The Haystack system has a number of features that rendered this option extremely attractive. It has a large diameter (120 ft) antenna needed to achieve deep-space ranges. The antenna was designed with Cassegrainian optics and could accommodate plug-in radio-frequency (RF) boxes at the vertex of the pa- raboloidal dish. These boxes supported various com- munications, radio astronomy, and radar functions. The interchangeable boxes are 8 × 8 × 12 ft, which is large enough for the high-power (400 kW peak and 200 kW average) new transmitter and associated mi- crowave plumbing, feedhorns, and low-noise receiv- ers needed for the long-range imaging radar.1 The Haystack antenna surface tolerance allows efficient operation up to 50 GHz, thus readily supporting op- erating at X-band (10 GHz) with a bandwidth of 1024 MHz, and a resulting range resolution of 0.25 m. A system for interchanging ground-based elec- tronics and power sources supporting the various RF boxes was already in place. Using an established facil- ity with existing antenna and prime power sources greatly reduced the cost of the new system, known as the Long Range Imaging Radar, or LRIR [6]. The LRIR, which was completed in 1978, is ca- pable of detecting, tracking, and imaging satellites out to synchronous-orbit altitudes, approximately 40,000 km. The range resolution of 0.25 m is matched by a cross-range resolution of 0.25 m for tar- gets that rotate at least 3.44° during the Doppler-pro- cessing interval. The wideband waveform is 256 μsec long and the bandwidth of 1024 MHz is generated by linear frequency modulation. The pulse-repetition frequency is 1200 pulses per second. The LRIR em- ploys a time-bandwidth exchange process similar to
################################### that of ALCOR to reduce signal bandwidth from ############################## 1024 MHz to a maximum of 4 MHz, corresponding #################################### to a range window of 120 m, while preserving the ################################# range resolution of 0.25 m ####################
kopija iz wische ....
This is accomplished in a time- bandwidth exchange technique (originated at the Air- borne Instrument Laboratory, in Mineola, New York) called stretch processing [4], ################### which retains range reso- lution but restricts range coverage to a narrow thirty- meter window.
To place a target in the wideband window, we first acquire the target with a continuous-wave acquisition pulse that is variable in length from 256 μsec (for short-range targets) to 50 msec (for long-range targets). An acquired target is then placed in active tracking by using 10-MHz- bandwidth chirped pulses, again of variable length, from 256 μsec to 50 msec. The wideband window is then designated to the target. Antenna beamwidth is 0.05°. Figure 3(a) shows an artist’s rendition of the 120-foot Haystack antenna in its 150-foot radome; Figure 3(b) shows a photograph of the LRIR feed horn and transmitter/receiver RF box in the Haystack radome
Отправлено: 05.11.10 03:24. Заголовок: mmw radar A second..
mmw radar
A second 35-GHz tube was also added, which doubled the average transmitted power. These modi- fications increased the signal pulse detection range on a one-square-meter target to over two thousand kilo- meters. System bandwidth was also increased to 2 GHz, resulting in a range resolution of about 0.10 m.
More recently, Lincoln Laboratory has developed and exploited several techniques for improving the 278 LINCOLN LABORATORY JOURNAL VOLUME 12, NUMBER 2, 2000 resolution of wideband coherent radar data. The first technique uses modern spectral-analysis methods for improving resolution relative to the restrictions of conventional Fourier processing. These spectral methods extrapolate signals in a radar-frequency di- mension by a process called bandwidth extrapolation. Each wideband pulse return includes the target fre- quency response over the chirped bandwidth. Mod- ern spectral-estimation techniques are then applied to extend this frequency response synthetically outside this band to a factor ranging from two to three times the bandwidth. This expanded pulse return is then re- compressed to provide finer range resolution (for practical signal-to-noise ratios, an improvement of a factor of two to three in resolution is generally real- ized), and when applied to radar imaging, it provides much improved sharpness in the radar image [9]. The second technique uses signal processing mod- els that correspond to rotating-point motion. The models allow extended coherent processing over wide target-rotation angles, resulting in improved Doppler (cross-range) resolution [10]. For sufficiently large resolution angles and for constant-amplitude scatter- ing centers, extended coherent processing also im- proves the range resolution. Extended coherent pro- cessing essentially aligns and stores radar pulses ob- tained over longer time spans as compared to conven- tional imaging. When combined with bandwidth ex- trapolation, extended coherent processing can achieve enhanced resolution in both range and Doppler (cross-range) spaces. For targets where the radar view- ing angle is at a constant aspect angle to the target’s angular-momentum vector, extended coherent pro- cessing provides high-quality three-dimensional radar images. More recently, the Laboratory has explored the possibility of achieving ultrawideband resolution by using data only over sparse subbands of the full ultra- wide bandwidth. We can view this technique as a gen- eralization of bandwidth extrapolation to multiple bands [10]. Ultrawideband’s potential as a discrimi- nation tool is much more robust, as scatterer-feature identification on a specific target is inherently more accurate when observed over a much wider band- width.
Wideband Radar for Ballistic Missile Defense and Range- Doppler Imaging of Satellites William W. Camp, Joseph T. Mayhan, and Robert M. O’Donnell s Lincoln Laboratory led the nation in the development of high-power wideband radar with a unique capability for resolving target scattering centers and producing three-dimensional images of individual targets. The Laboratory fielded the first wideband radar, called ALCOR, in 1970 at Kwajalein Atoll.
35 ghz /2000 mgz mmw radar s 13.6 metra D antennoj 0.042 gradschirinoj lucha na 35 ghz(0.014 grad na 94 ghz) i razrescheniem 100 mm pri polose 2000 mgz
Отправлено: 05.11.10 03:55. Заголовок: As shown in Figure 1..
As shown in Figure 17, the signal is then downconverted to 60 MHz, input to an automatic- gain control (AGC) network, and band limited to 5 MHz. The resulting 60-MHz signal is once again mixed, to yield a 5-MHz sig- nal at an IF of 5 MHz. This final signal can be succinctly described as (4) where fi/ is the 5-m~ fA is the frequency-encoded range IF, term, and -2.5 MHz < f,, c 2.5 MHz. The resulting signal is sam- pled by a IO-bit 20-MHz A/D converter over the 50-its pulse, resulting in 1000 samples which are input to the digital portion of the pulse-compression system.
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