Thursday, December 18, 2008

В "МиГи" подсадили "Жука".

Российская корпорация "Фазотрон-НИИР" завершила разработку новейшей бортовой радиолокационной станции "Жук-АЭ" для истребителей МиГ-35 с активной фазированной решеткой. По словам гендиректора фирмы Вячеслава Тищенко, это первая изготовленная в России активная фазированная антенная решетка. Ее появление приближает наш истребитель к главному конкуренту - американскому истребителю пятого поколения F-35. Теперь наш "МиГ" способен конкурировать с F-35 не только в воздушных боях, но и на мировых рынках вооружений.

Считается, что Россия отстает от США в области разработки перспективных авиационных комплексов нового, пятого поколения. У американцев уже есть тяжелый истребитель F-22 Raptor, который запущен в серийное производство. F-35 пока проходит стадию испытаний. Но уже сейчас ясно, что это будет одна из самых перспективных боевых машин мира. США и их союзники уже сделали заказ на более чем 3 тысячи таких истребителей. У нас пока больше думают, чем ответить американцам. Как говорят в КБ "Сухой", в фирме, выигравшей гостендер на разработку перспективного истребителя, "все идет по плану". В Комсомольске-на-Амуре уже собирают первые образцы новой машины, перспективный двигатель для нее С-117 проходит обкатку на новейшем Су-35.

Появление обновленного "МиГа" - событие того же порядка. От обычного МиГ-29 его отличает обновленная электронная "начинка". Все системы самолета управляются бортовыми компьютерами. Вместо аналоговых - стрелочных приборов - жидкокристаллические панели. Новейшие двигатели питерского КБ "Климов" РД-33МК с полностью поворотными соплами. Причем не только в режиме "нормального" полета, но и на форсаже. Это свойство радикально отличает МиГ-35 от того же Су-30МКИ или американского F-22 и F-35.

Однако в современном бою всего этого недостаточно, если машина и пилоты "слепы". "Жук-АЭ" как раз и решает эту проблему. До ее появления такие локаторы устанавливались лишь на самых современных американских истребителях, а Западная Европа создать их пока не смогла. Установка этого комплекса вплотную приблизит наш МиГ-35 к западным конкурентам, а заодно повысит шансы на победу в предстоящем индийском тендере по программе MMRCA на поставку Дели 126 истребителей. Попробуем разобраться в деталях.

На предыдущих наших самолетах устанавливались параболические или щелевые антенны. Они имели по одному приемнику и передатчику сигнала. Активная фазированная антенная решетка построена по принципу пчелиной соты, состоящей из 680 миниатюрных приемо-передающих устройств. Такая антенна (опять же в отличие от "предшественниц") монолитна, то есть не поворачивается из стороны в сторону в поиске целей. Это экономит не только вес устройства (ей электродвигатели больше не нужны), но и на порядок сокращает время обнаружения радаром целей - сканирующий луч перебрасывается из одной точки антенны в другую в доли секунды.

Угол зрения у нового "Жука" плюс-минус 60 градусов. Дальнозоркость - 140 км. Он может одновременно сопровождать 30, а обстреливать 6 целей. Причем как в воздухе, так и на земле. При этом новая антенна позволяет решать еще ряд задач. Передавать данные о тактической обстановке на другие самолеты, вести радиолокационную борьбу, картографирование местности. Точно так же, как это сделано в американском F-35.

По словам главы Объединенной авиастроительной корпорации Алексея Федорова, все это позволяет говорить о МиГ-35, как одном из самых перспективных российских истребителей, который по своим возможностям приближается к боевым самолетам нового поколения. В случае победы в тендере, как отмечают российские эксперты, Индия получит не только сам истребитель, но и технологию производства новых радиолокационных станций с активной фазированной антенной решеткой.

Дмитрий Литовкин

15.12.2008
Права на данный материал принадлежат Финансовые известия.
Материал был размещен в открытом доступе на АвиаПорт.ru.

Tuesday, December 9, 2008

Sound of the Duga-3 transmitter

The Russian Woodpecker (DUGA-3 near Chernobyl, Ukraine) early warning radar was a notorious Soviet signal that could be heard on the shortwave radio bands worldwide between July 1976 and December 1989. It sounded like a sharp, repetitive tapping noise, at 10 Hz, giving rise to the "Woodpecker" name.

Wednesday, December 3, 2008

RAF's Innovative ASTOR Radar Now in Service

The British MoD has officially declared the innovative ASTOR (airborne stand-off radar) system in service onboard the RAF's Sentinel R1 aircraft.

The ASTOR System, which was developed under a £860m contract by Raytheon Systems, provides new all-weather intelligence, surveillance, target acquisition and reconnaissance capability to assist commanders on the battlefield.

Royal Air Force Sentinel R.1 visits the National Test Pilot School at Mojave

ASTOR is also designed to communicate with a wide range of other systems and networks and is therefore at the heart of the UK's network-enabled capability (NEC).

Minister for Defence Equipment and Support, Quentin Davies said that the advanced technology will deliver exceptional surveillance capabilities. "The ASTOR radar will link up with other intelligence-gathering equipment providing commanders with a complete picture of the ground allowing them to make immediate decisions on operations," Davies said.

Sunday, October 5, 2008

Annotated bibliography - "Pulse compression in Radars"

Listing are chronological

  • Woodward, P.M., Probability and Information Theory, With Applications to Radar, New York: McGraw-Hill Book Co. (1955).
    Fundamentals of resolution theory and ambiguity functions, including linear-FM pulse.
  • Cook, C.E., "Modification of Pulse-Compression Waveforms," Proc. NEC 14, 1958, pp 1058-67.
    Basic paper on linear FM pulse compression technique.
  • Cook, C.E., "Pulse Compression-Key to More Efficient Radar Transmission," Proc IRE 48, No 3, Mar. 60, pp 310-316.
    Basic paper on linear-FM pulse compression technique. Reprint Paper No. 1 in Source.
  • Westerfield, E.C., Prager, R.H. and Stewart, J.L. "Processing Gains Against Reverberation (Clutter) Using Matched Filters," IRE Trans IT-6, No 3, Jun 1960, pp 342-349.
    Use of Woodward ambiguity function to calculate signal-to-clutter ratio in radar and sonar systems.
  • Klauder, J.R. et. al., "The Theory and Design of Chirp Radars," BSTJ 39, No 4, Jul 1960, pp 745-808.
    Basic paper on linear-FM pulse compression theory, sidelobe reduction, and error effects. Reprint Paper No. 2 in Source.
  • Klauder, J.R., "The Design of Radar Signals Having Both High Range Resolution and High Velocity Resolution," BSTJ 39, No 4, Jul 1960, pp 809-820.
    Derivation of waveform having circularly symmetric ambiguity function. Required amplitude modulation precludes efficient transmission.
  • Key, F.L., Fowle, E.N. and Haggarty, R.D., "A Method of Designing Signals of Large Time-Bandwidth Product," IRE Conv Record, 1961, Pt. 4, pp 146-154.
    Design of signals for which envelope shape and autocorrelation function are separately specified.
  • Ramp, H.O. and Wingrove, E.R., "Principles of Pulse Compression," IRE Trans M/L-5, No 2, Apr 1961, pp 109-116.
    Basic paper on linear-FM pulse compression principles and applications. Reprint Paper No. 3 in Source.
  • Cook, C.E., "General Matched-Filter Analysis of Linear FM Pulse Compression," Proc IRE 49, No 4, Apr 1961, p 831.
    Considers effect of Doppler shift on output waveform of filter matched to linear-FM signal, including bandwidth restriction.
  • DiFranco, J., "Closed-Form Solution for the Output of a Finite-Bandwidth Pulse-Compression Filter," Proc IRE 49, No 6, Jun 1961, pp 1086-87.
    Evaluation of integrals leading to output waveform in band limited cases.
  • DiFranco, J.V. and Rubin, W.L., "An Interpretation of 'Paired Echo Theory' for Time-Domain Distortion in Pulsed Systems and an Extension to the Radar 'Uncertainty Function'," Proc IRE 49, No 9, Sep 1961, pp 1432-1433.
    Description of spurious outputs caused by frequency-domain and time-domain distortions.
  • Reed, J., "Long-Line Effect in Pulse Compression Radar," Microwave Journal 4, No 9, Sep 1961, pp 99-100.
    Effect of transmission line mismatch on phase-vs-frequency response of radar system. Reprint Paper No. 4 in Source.
  • Ramp, H.О. and Wingrove, E.R., "Performance Degradation of Linear FM Pulse Compression," Proc IRE 49, No 11, Nov 1961, p 1693.
    Analysis of output waveform of Doppler shifted signal, including second-order Doppler terms which can be important for large time-bandwidth product.
  • Cook, C.E., "Effects of Phase-Modulation Errors on Radar Pulse Compression Signals," IRE Conv Record, 1962, Pt 4, pp 174-184.
    Analysis and experimental data on effect on sinusoidal phase errors on output waveform.
  • Thor, R.C., "A Large Time-Bandwidth Product Pulse Compression Technique," IRE Trans MIL-6, No 2, Apr 1962, pp 169-173.
    Use of logarithmic, rather than linear, frequency modulation is shown to permit use of greater time-bandwidth products on targets with large radial velocity. Reprint Paper No. 5 in Source.
  • DiFranco, J.V. and Rubin, W.L., "Analysis of Signal Processing Distortion in Radar Systems," IRE Trans MIL-6, No 2, Apr 1962, pp 219-227.
    Describes effects of phase and amplitude distortion on ambiguity function shape and sidelobe levels.
  • Cook, C.E. and Heiss, W.H., "Linear FM Pulse Compression Doppler Distortion Effects," Proc IRE 50, No 6, Jun 1962, pp 1535-1536.
    Further discussion of dispersive Doppler effect and different viewpoints of Cook (1961) and Ramp and Wingrove (1961).
  • Fryberger, D., "On the Use of Pulse Compression for the Enhancement of Radar Echoes from Diffuse Targets," Proc IRE 50, No 9, Sep 1962, pp 1993-1994.
    Compares effect of pulse compression on SNR and resolution for diffuse and discrete targets.
  • Rubin, W.L. and DiFranco, J.V., "The Effects of Doppler Dispersion on Matched Filter Performance," Proc IRE 50, No 10, Oct 1962, pp 2127-2128.
    Expressions are derived for the difference between simple frequency shift and Doppler shift with dispersion, and it is shown that this difference is negligible for time-bandwidth products less than 1000.
  • Fowle, E.N. el. al., "A Pulse Compression System Employing a Linear FM Gaussian Signal." Proc IEEE 51, No 2, Feb 1963, pp 304-312.
    Design and equipment considerations for low-sidelobe pulse compression systems using approximations to Gaussian weighting.
  • Cook, C.E., "Pulse-Compression Paired-Echo Experiments," Proc IEEE 51, No 2, Feb 63, pp 383-384.
    Experimental verification of paired-echo response caused by sinusoidal phase errors in pulse compression signal.
  • Temes, C.L. et. al. "Pulse Compression System for a Down-Range Tracker," IEEE Conv Rec 1963, Pt 8, pp 71-81.
    Description of 4 MHz 2 ms pulse compression waveform for 425 MHz instrumentation radar.
  • Cook, C.E., "Transmitter Phase Modulation and Pulse Compression Waveform Distortion," Microwave Journal 6, No 5, May 1963, pp 63-69.
    Analysis of paired-echo effect of sinusoidal phase error, and sidelobe increase caused by localized phase error in chirp signal. Reprint Paper No. 6 in Source.
  • Minis, W.B., "The Detection of Chirped Radar Signals by Means of Electron Spin Echoes," Proc IEEE 51, No 8, Aug 1963, pp 1127-1134.
    Theory and experimental results using compression filter based on paramagnetic resonance line at 6.7 GHz.
  • Bernfeld, M., "Pulse Compression Techniques," Proc IEEE 51, No 9, Sep 63, p 1261.
    Comparison of systems using series and parallel dispersive elements to generate large time-bandwidth products.
  • Lurin, E.S., "Digital Pulse Compression Using Polyphase Codes," Proc IEEE 51, No 9, Sep 63, pp 1262-1263.
    Implementation and ambiguity function of digital equivalent of linear and triangular-FM pulse compression.
  • Fowle, F.N., "The Design of FM Pulse Compression Signals," IEEE Trans IT-10, No 1, Jan 1964, pp 61-67.
    Discusses design of waveform having arbitrary transmitted envelope, to produce given autocorrelation function.
  • Cook, C.E. and Paolillo, J., "A Pulse Compression Predistortion Function for Efficient Sidelobe Reduction in a High-Power Radar," Proc IEEE 52, No 4, Apr 1964, pp 377-89.
    Describes use of increased sweep rate on leading and trailing edges of pulse to reduce paired-echo sidelobes.
  • Cook, C.E., "A Class of Nonlinear FM Pulse Compression Signals," Proc IEEE 52, No 11, Nov 1964, pp 1369-1371.
    Analysis of nonlinear chirp to achieve sidelobe reduction, showing sensitivity to Doppler shift.
  • Bernfeld, M. et. al., "Matched Filtering, Pulse Compression and Waveform Design," Microwave Journal, Oct, Nov, Dec 1964; Jan 1965, pp 57-64, 81-90, 70-76, 73-81.
    Thorough discussion and analysis of linear and nonlinear FM and discrete code waveforms and their ambiguity functions. Reprint Paper No. 7 in Source.
  • Bogotch, S.E. and Cook, C.E., "The Effect of Limiting on the Detectability of Partially Time Coincident Pulse Compression Signals," IEEE Trans M/L-9, No 1, Jan 1965, pp 17-24.
    Theory and experimental results on suppression of small signals by overlap of expanded pulse from large, adjacent signal which would be resolvable except for receiver limiting. Reprint Paper No. 8 in Source.
  • Peebles, P.Z. and Stevens, G.H., "A Technique for the Generation of Highly Linear FM Pulse Radar Signals," IEEE Trans M/L-9, No 1, Jan 1965, pp 32-38.
    A method is described for generating a staircase FM waveform, closely approximating linear sweep with very high accuracy.
  • Rihaczek, A.W., "Radar Signal Design for Target Resolution," Proc IEEE 53, No 2, Feb 1965, pp 116-128.
    Relationships between resolution and measurement uncertainty are explored for different signals and clutter environments.
  • Rihaczek, A.W., "Range Accuracy of Chirp Signals," Proc IEEE 53, No 4, Apr 1965, pp 412-13.
    It is shown that the diagonal ambiguity of chirp signals does not lead to range uncertainty on targets of unknown Doppler if the range reading is interpreted as applying at a time displaced from the actual echo time. Reprint Paper No. 9 in Source.
  • Jacob, J.S., "Graphical Comparison of a Doppler-Shift Advantage for Three Pulse-Compression Techniques," Proc 9th Natl Conv on Military Electr, IELE, Wash, D.C., 1965, pp 382-387.
    Degradation in SNR with Doppler shift is compared for three waveforms, and linear FM is shown to be affected less than phase-coded or frequency-stepped waveforms.
  • Ward, M.X., ''Matched Scan Rate Pulse-Compression Analysis," Proc IEEE 54, No 4, Apr 1966, pp 707-708.
    Derives output waveform for compression filter with arbitrary impulse response duration, showing approach to (sin x)/x shape for long durations.
  • Rihaczek, A.W., "Doppler-Tolerant Signal Waveforms," Proc IEEE 54, No 6, Jun 1966, pp 849-857.
    Discussion of non-linear FM modulations and pulse trains for which Doppler distortions can be ignored.
  • Hollis, E.E., "Comparison of Combined Barker Codes for Coded Radar Use," IEEE Trans AES-3, No 1, Jan 1967, pp 141-143.
    Sidelobe levels are determined for sequences of four 13-bit Barker Codes and thirteen 4-bit codes, showing maximum amplitude 13/52 times main lobe.
  • Lipman, M.A. "A Useful Property of the Generalized Chirp Signal Ambiguity Function," Proc IEEE 55, No 7, Jul 1967, pp 1241-1242.
    Ambiguity function generalized to include mismatched sweep rate as well as delay and Doppler shift.
  • Cook, C.E. and Bernfeld, M. Radar Signals, New York: Academic Press, 1967.
    Basic text on pulse compression principles and implementation.
  • Kibbler, G.O.T.H., "The CLFM: a Method of Generating Linear Frequency-Coded Radar Pulses," IEEE Trans AES-4, No 3, May 68, pp 385-391.
    Describes coherent linear frequency modulator used in active generation of chirp signals and in conversion of received signals to constant frequency.
  • Mitchell, R.L. and Rihaczek, A.W., "Matched-Filter Responses of the Linear FM Waveform," IEEE Trans AES-4, No 3, May 1968, pp 417-432.
    Equations and three-dimensional plots of ambiguity functions with and without weighting and mismatch.
  • Rihaczek, A.W., and Mitchell, R.L., "Design of Zigzag FM Signals," IEEE Tram AES-4, No 5, Sep 1968, pp 680-692.
    Presents three-dimensional plots of ambiguity functions of simple and multiple-segment zigzag FM waveforms.
  • Haggarty, R.D., Hart, L.A. and O'Leary, G.C, "A 10.000 to 1 Pulse Compression Filter Using a Tapped Delay Line Linear Filter Synthesis Technique," IEEE EASCON Rec, 1968, pp 306-314.
    Synthesis procedure and experimental results on delay-line filters for large time-bandwidth product pulse compression and other applications. Reprint Paper No. 10 in Source.
  • Belknap, D.J., "An Experimental Measurement of the Detection Capability of a Linear FM Pulse Compression System," IEEE EASCON Rec, 1968, pp 315-318.
    Detection performance of 1000:1 pulse compression system is compared with ideal matched filter and with Doppler filter bank. Results are within a fraction of a dB of the matched filter.
  • Ruttenberg, K. and Chanzit, L., "High Range Resolution by Means of Pulse-To-Pulse Frequency Shifting," IEEE EASCON Record, 1968, pp 47-51.
    Method of obtaining resolution in system using agile magnetron rather than intrapulse FM. Reprint Paper No. 11 in Source.
  • Leith, E.N., "Optical Processing Techniques for Simultaneous Pulse Compression and Beamsharpening," IEEE Trans AES-4, No 6, Nov 1968, pp 879-885.
    Combined processing for synthetic aperture resolution and pulse compression, using two-dimensional optical filter.
  • Bechtel, M.E., "Generalized Paired-Echo Analysis for Band-pass Systems," Proc IEEE 57, No 2, Feb 1969, pp 204-205.
    Description of phase and amplitude distortion terms in bandpass systems in terms of advanced and delayed replicas of ideal signal.
  • Palmieri, C.A. and Cook, C.E., "The Ambiguity Properties of Multiple-Segment Linear FM Signals," Proc IEEE 57, No 7, Jul 1969, pp 1323-1325.
    Approximate analysis of mainlobe and near-sidelobe response of multiple-segment FM waveforms.
  • Vannicola, V.C., "Range Dependent Waveform of an Active Weighted Pulse Compression Receiver," IEEE Trans AES-5, No 5, Sep 1969, pp 847-864.
    Output waveforms for pulse compression systems in which the signal is time weighted by a function not exactly centered on the received signal. Reprint Paper No. 12 in Source.
  • Nathanson, F.E., Radar Design Principles, New York, McGraw-Hill, 1969.
    Text covering radar clutter and resolution requirements, with chapters devoted to phase coding and to linear-FM processing techniques.
  • Rihaczek, A.W., Principles of High-Resolution Radar, New York: McGraw-Hill, 1969.
    Basic text on waveform design and results in resolution, detection and measurement in clutter.
  • Campbell, B.D., "High-Resolution, Radar Coherent Linear FM Microwave Source," IEEE Trans AES-6, No 1, Jan 1970, pp 62-72.
    Design of BWO generator for 16 Hz FM Sweep at S-band.
  • Millett, R.E., "A Matched-Filter Pulse-Compression System Using a Nonlinear FM Waveform," IEEE Trans AES-6, No 1, Jan 1970, pp 73-78.
    Design and test data on low-sidelobe pulse compression waveform having 0.1 dB mismatch loss. Reprint Paper No 13 in Source.
  • Cohen, S.A., "Generalized Response of a Linear FM Pulse Compression Matched Filter," IEEE Trans AES-6, No 5, Sep 1970, pp 708-712.
    Curves are derived which show losses in peak output caused by mismatch of pulse width, sweep rate and center frequency.
  • Caputi, W.J., Jr., "Stretch: A Time-Transformation Technique," IEEE Trans AES-7, No 2, Mar 1971, pp 269-278.
    Technique for very high resolution with relatively simple processor covering a limited range window. Reprint Paper No. 14 in Source.
  • Hartt, J.K. and Sheats, L.F., "Application of Pipeline FFT Technology in Radar Signal and Data Processing," IEEE EASCON Record 1971, pp 216-221.
    Pipeline FFT processors for pulse compression and Doppler filtering are described. Reprint Paper No. 15 in Source.
  • Halpern, H.M. and Perry, R.P. "Digital Matched Fitters Using Fast Fourier Transforms," IEEE EASCON Record 1971, pp 222-230.
    A 10-MHz bandwidth digital filter, suitable for high-resolution pulse compression, is described. Effects of different word lengths for signal and reference waveforms are explored by simulation. Reprint Paper No. 16 in Source.
  • Woerrlein, N.H., "Spurious Target Generation Due to Hard Limiting in Pulse Compression Radars," IEEE Trans AES-7, No 6, Nov 1971, pp 1170-1178.
    Method and results for calculating spurious outputs caused by hard limiting of three overlapping signals, using phase-coded waveform.
  • Rihaczek, A.W., "Radar Waveform Selection-A Simplified Approach," IEEE Trans AES-7, No 6, Nov 1971, pp 1078-1086.
    Waveforms are divided into four classes, each with distinct resolution properties, permitting a systematic approach to waveform selection. Reprint Paper No 17 in Source.
  • Jones, W.S., Kempf, R.A. and Hartmann, C.S., "Practical Surface Wave Chirp Fillers for Modern Radar Systems," Microwave Journal, May 1972.
    Design, application and performance of surface acoustic wave filters for 8 MHz x 12.5 usec and 2 MHz x 25 usec pulse compression. Reprint Paper No 18 in Source.
  • Ackroyd, M.H. and Ghani, F., "Optimum Mismatched Filters for Sidelobe Suppression," IEEE Trans AES-9, No 2, Mar 1973, pp 214-218.
    At some expense in complexity and small loss in SNR, time sidelobes can he reduced without amplitude weighting on transmit.
  • Powell, Т.Н., Jr. and Sinsky, A.I., "A Time Sidelobe Reduction Technique for Small Time-Bandwidth Chirp," IEEE Trans AES-10, No 3, May 1974, pp 390-392.
    Digital filter design to compensate for effect of Fresnel ripples in spectrum of chirp signal.
  • Hollan, M.G. and Claiborne, L.T., "Practical Surface Acoustic Wave Devices," Proc IEEE 62, No 5, May 1974, pp 582-611.
    Tutorial discussion of SAW devices and their application, with extensive bibliography.
  • Fitzgerald, R.J., "Effects of Range-Doppler Coupling on Chirp Radar Tracking Accuracy," IEEE Trans AES-10, No 4, Jul 1974, pp 528-532.
    Describes interaction of chirp range-Doppler coupling with truncation error of GHK filler, such that positive chirp slope leads to reduced error of filtered data.
  • Caputi, W.J., "Stabilized Linear FM Generator," IEEE Trans, AES-9, No 5, Sep 1973, pp 570-578.
    Closed-loop technique for controlling slope of linear frequency sweep generator, as applied to 240 MHz x 120 usec active pulse-compression waveform generator.

Source: Radars. Vol 3. Pulse Compression. By David K. Barton. Dedham: Artech House, Inc., 1975.

Friday, October 3, 2008

High-Resolution Radar Data Assimilation for Hurricane Isabel (2003) at Landfall

Assimilating observations from five WSR-88D radars into a mesoscale numerical weather prediction model improves the structure and intensity predictions of the landfalling hurricane. - Reference

 

 

in September 2008 issue of

Bulletin of the American Meteorological Society

Tuesday, September 30, 2008

An Evaluation of Two NEXRAD Wind Retrieval Methodologies and Their Use in Atmospheric Dispersion Models

Two entirely different methods for retrieving 3D fields of horizontal winds from Next Generation Weather Radar (NEXRAD) radial velocities have been evaluated using radar wind profiler measurements to determine whether routine wind retrievals would be useful for atmospheric dispersion model applications. The first method uses a physical algorithm based on four-dimensional variational data assimilation, and the second simpler method uses a statistical technique based on an analytic formulation of the background error covariance. Both methods can be run in near–real time, but the simpler method was executed about 2.5 times as fast as the four-dimensional variational method. The observed multiday and diurnal variations in wind speed and direction were reproduced by both methods below 1.5 km above the ground in the vicinity of Oklahoma City, Oklahoma, during July 2003. However, wind retrievals overestimated the strength of the nighttime low-level jet by as much as 65%. The wind speeds and directions obtained from both methods were usually similar when compared with profiler measurements, and neither method outperformed the other statistically. Within a dispersion model framework, the 3D wind fields and transport patterns were often better represented when the wind retrievals were included along with operational data. Despite uncertainties in the wind speed and direction obtained from the wind retrievals that are higher than those from remote sensing radar wind profilers, the inclusion of the wind retrievals is likely to produce more realistic temporal variations in the winds aloft than would be obtained by interpolation using the available radiosondes, especially during rapidly changing synoptic- and mesoscale conditions.- Reference

Maximum Position Alignment Method for Noisy High-Resolution Radar Target Classification

In this paper, the alignment of noisy high-resolution radar signals using the maximum position method is studied. The relationship between the shift estimation and the signal-to-noise ratio is considered. As a result, two analytical expressions are obtained that approximate the root-mean-square error of the difference in the shift estimation with and without noise. These two expressions allow us to improve the understanding of the sensitivity to noise of the Maximum Position alignment method. - Reference

Predicted Detection Performance of MIMO Radar

It has been shown that multiple-input multiple-output (MIMO) radar systems can improve target detection performance significantly by exploiting the spatial diversity gain. We introduce the system model in which the radar target is composed of a finite number of small scatterers and derive the formula to evaluate the theoretical probability of detection for the system having an arbitrary array-target configuration. The results can be used to predict the detection performance of the actual MIMO radar without time-consuming simulations. - Reference

Radar Revisited (review of "Radar Handbook, 3rd ed." by Merrill Skolnik) [Book Reviews]

This is the third edition of an established handbook, edited by one of the most-recognized names in the field of radar technology. The volume is a compilation of 26 chapters, authored by individuals with a thorough command of, and incredible credentials in, the topics of their chapters. Most chapters have a large number of figures (up to several dozen) and extensive bibliographies. Chapters range from fairly quantitative and mathematical ones to cursory and descriptive ones. Some sections of the handbook represent a concise and readable summary of the state-of-the-art of knowledge on their topics; others are a sketchy collection of remarks for which it is difficult to identify the benefits to be derived by the reader. There is little coordination between chapters where similar topics may be discussed, and a lack of any cross-referencing. There are also weaknesses in the index, as well. While the older, classical radar topics receive much attention, the book overlooks newer areas such as coverage of automotive radars. This volume will appeal to the generalists with interest in the conventional radar subjects, and to others as a starting point for locating sources with more detailed information. - Reference

An Orientation-Selective Orthogonal Lapped Transform

A novel critically sampled orientation-selective orthogonal lapped transform called the lapped Hartley transform (LHT) is derived. In a first step, overlapping basis functions are generated by modulating basis functions of a 2-D block Hartley transform by a cosine wave. To achieve invertibility and orthogonality, an iterative filter is applied as prefilter in the analysis and as postfilter in the synthesis operation, respectively. Alternatively, filtering can be restricted to analysis or synthesis, ending up with a biorthogonal transform (LHT-PR, LHT-PO). A statistical analysis based on a 4000-image data base shows that the LHT and LHT-PO have better redundancy removal properties than other block or lapped transforms. Finally, image compression and noise removal examples are given, showing the advantages of the LHT especially in images containing oriented textures. - Reference

Texture Analysis and Classification With Linear Regression Model Based on Wavelet Transform

The wavelet transform as an important multiresolution analysis tool has already been commonly applied to texture analysis and classification. Nevertheless, it ignores the structural information while capturing the spectral information of the texture image at different scales. In this paper, we propose a texture analysis and classification approach with the linear regression model based on the wavelet transform. This method is motivated by the observation that there exists a distinctive correlation between the sample images, belonging to the same kind of texture, at different frequency regions obtained by 2-D wavelet packet transform. Experimentally, it was observed that this correlation varies from texture to texture. The linear regression model is employed to analyze this correlation and extract texture features that characterize the samples. Therefore, our method considers not only the frequency regions but also the correlation between these regions. In contrast, the pyramid-structured wavelet transform (PSWT) and the tree-structured wavelet transform (TSWT) do not consider the correlation between different frequency regions. Experiments show that our method significantly improves the texture classification rate in comparison with the multiresolution methods, including PSWT, TSWT, the Gabor transform, and some recently proposed methods derived from these. - Reference

Orientation Angle Distributions of Drops after an 80-m Fall Using a 2D Video Disdrometer

This note reports on the use of a 2D video disdrometer to estimate the orientation of drops (>2 mm) that were generated artificially and allowed to fall 80 m from a bridge with no obstruction and under calm conditions. This experimental setup enabled a large number of drops to be generated, up to 10 mm in horizontal dimension.

The distribution of the canting angles for all drops >2 mm was found to be nearly symmetric about 0° with standard deviation between 7° and 8°. From the canting angle distributions derived from the two orthogonal camera view planes, the distributions of the polar (θ) and azimuth () angles were deduced; these two angles describe the 2D orientation of the symmetry axis. The azimuthal angle distribution was found to be nearly uniform in the range (0, 2π), whereas the distribution of pΩ(θ) = p(θ) sinθ was similar in shape to a special form of the Fisher distribution that is valid for describing the statistics on a spherical surface. The standard deviation of pΩ(θ) showed that larger drops are more stably oriented than smaller ones. This is in agreement with previous radar-based results of standard deviation of the canting angle decreasing with increasing Zdr.-Reference

Measurements of the Transmission Loss of a Radome at Different Rain Intensities

Results on the transmission loss of a dry and a wet C-band weather radar radome at different rain intensities are presented. Two methods were used in the study, both carried out under laboratory conditions. In the first method, the complex permittivity of a dry radome is measured and the transmission loss calculated. To analyze the transmission loss of a wet radome, the thickness of a continuous water layer on the surface of a radome at different rain intensities and the complex permittivity of water are calculated. In the second method, the transmission loss is measured as a free space transmission measurement with a 1.3-m2 piece of a radome panel. The piece is measured as dry and as doused by a rain system designed for the measurements. The measurements are performed with a dirty, cleaned, and waxed radome to examine the effects of maintenance measures with an old radome on the transmission loss. Because the transmission loss as a function of rain intensity is measured with a small piece of radome, a method is developed to scale the free space measurements for a complete 6.7-m-diameter radome with equal dielectric properties. Results of the one-way transmission loss of a dry radome with the permittivity and free space measurements are in a good agreement (0.34 and 0.35 dB, respectively). According to the analysis, a continuous water layer on a radome has a significant influence on the transmission loss. A 3-dB two-way transmission loss caused by a dirty radome is observed at a rain intensity of 15.1 mm h−1. Waxing gives promising results in reducing the wet radome loss because the waxing prevents the formation of a continuous water layer on the surface of the radome.- Reference

A Study on Optimum Tilt Angle for Wind Estimation Using Indian MST Radar

The effect of tilt angle on horizontal wind estimation is studied using Indian mesosphere–stratosphere–troposphere (MST) radar located at Gadanki (13.45°N, 79.18°E). It operates in Doppler beam swinging (DBS) mode with a beamwidth of 3°. Horizontal winds are computed for different tilt angles from 3° to 15° with an increment of 3° from a height range of 3.6–18 km. The effective beam pointing angle (θeff) is calculated to determine the effect of aspect sensitivity on the determination of horizontal wind components. For different tilt angles radar-derived winds are compared with simultaneous GPS sonde wind measurements, which were launched from a nearby site. The first method utilizes direct comparison of radar-derived winds with those of GPS sondes using the actual beam pointing angle; the second method uses the effective beam pointing angle derived from the ratios of two oblique beams. For this study a variety of statistics were explored in terms of standard deviation, correlation coefficient, and percentage error. From the results it is observed that in agreement with previous studies, the effective beam pointing angle deviates from the actual beam pointing angle, which results in the underestimation of horizontal wind components, and also when tilt angle is close to zenith and far from zenith, the estimation of horizontal winds is found to be far from true values at different heights. Radar wind estimation has better agreement with GPS sonde measurement when the off-zenith angle is around 10°. It is also found that correction to the actual beam pointing angle provides 3%–6% improved agreement between the radar and GPS wind measurements. -Reference

Multiple Scattering Effects in Pulsed Radar Systems: An Intercomparison Study

In this paper, two different numerical methods capable of computing multiple scattering effects in pulsed-radar systems are compared. Both methods are based on the solution of the time-dependent vectorial form of the radiative transfer equation: one exploits the successive order of scattering approximation, the other a forward Monte Carlo technique.

Different benchmark results are presented (including layers of monodisperse spherical water and ice particles), which are of specific interest for W-band spaceborne cloud radars such as CloudSat’s or EarthCARE’s cloud profiling radars. Results demonstrate a good agreement between the two methods. The pros and cons of the two models are discussed, with a particular focus on the validity of the second order of scattering approximation.- Reference

Differential Reflectivity Calibration for Operational Radars

The conventional technique for calibrating $Z_{dr}$ using natural scatterers is based on vertical-looking observations. In some operational weather radar, this method is not applicable because of mechanical constraints that prohibit vertical measurement or choices in the scanning strategies. A technique for calibrating $Z_{dr}$ based on properties of rain returns is proposed and analyzed. The technique is based on an examination of properties of differential reflectivity measurements collected at increasing elevations. Differential reflectivity observed in rain decreases with increasing elevation due to the increasing view angle. Using the hypothesis of uniform microphysical profiles below the bright band, deviations of the profile of differential reflectivity with elevation with respect to the theoretical profile can be used to detect and quantify the presence of a bias on differential reflectivity. To apply this concept in the presence of a nonuniform microphysical profile, the contribution of vertical changes in microphysics to $Z_{dr}$ variation in height is also accounted for. An error parameter associated with the estimated $Z_{dr}$ bias can be used as a quality indicator of the bias estimation; it allows definition of a criterion based on a threshold of root-mean-square error that permits acceptance or rejection of a $Z_{dr}$ bias estimation obtained with the proposed method. The technique is demonstrated using data collected by an operational weather radar at Arpa Piemonte (Italy) and evaluated using independent disdrometer measurement. Results show that under certain conditions discussed in the paper, this method can provide $Z_{dr}$ calibration within an accuracy of 0.1 dB. - Reference

Simulating Range Oversampled Doppler Radar Profiles of Inhomogeneous Targets

A new technique for generating range oversampled profiles of Doppler radar signals that have been backscattered by distributed targets is presented in this paper. The technique was developed for spaceborne cloud radars, but it can just as well be used for ground-based precipitation or wind-profiling radars. The technique is more versatile than the traditional inverse FFT technique and faster than the individual hydrometeor simulation (Monte Carlo) technique. Doppler radar signals from backscattering hydrometeors are essentially correlated stochastic variables. The technique uses an accurate description of covariances between voltages measured for different pulses and at different positions (range gates) along a profile. A matrix formalism is developed to subsequently transform uncorrelated Gaussian noise into correlated receiver voltages with the appropriate covariances. In particular, the new technique deals with target variability in a physically consistent manner, accounting for the effects of inhomogeneity both within the instantaneous field of view and between subsequent pulses. The new technique is showcased with examples of simulated 95-GHz Doppler radar observations by the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) space mission. - Reference

Monday, September 29, 2008

A Technique for the Automatic Detection of Insect Clutter in Cloud Radar Returns

The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Program operates 35-GHz millimeter-wavelength cloud radars (MMCRs) in several climatologically distinct regions. The MMCRs, which are centerpiece instruments for the observation of clouds and precipitation, provide continuous, vertically resolved information on all hydrometeors above the ARM Climate Research Facilities (ACRF). However, their ability to observe clouds in the lowest 2–3 km of the atmosphere is often obscured by the presence of strong echoes from insects, especially during the warm months at the continental midlatitude Southern Great Plains (SGP) ACRF. Here, a new automated technique for the detection and elimination of insect-contaminated echoes from the MMCR observations is presented. The technique is based on recorded MMCR Doppler spectra, a feature extractor that conditions insect spectral signatures, and the use of a neural network algorithm for the generation of an insect (clutter) mask. The technique exhibits significant skill in the identification of insect radar returns (more than 92% of insect-induced returns are identified) when the sole input to the classifier is the MMCR Doppler spectrum. The addition of circular polarization observations by the MMCR and ceilometer cloud-base measurements further improve the performance of the technique and form an even more reliable method for the removal of insect radar echoes at the ARM site. Recently, a 94-GHz Doppler polarimetric radar was installed next to the MMCR at the ACRF SGP site. Observations by both radars are used to evaluate the potential of the 94-GHz radar as being insect free and to show that dual wavelength radar reflectivity measurements can be used to identify insect radar returns. - Reference

Potential Role Of Dual- Polarization Radar In The Validation Of Satellite Precipitation Measurements: Rationale and Opportunities

Ground based dual-polarization radars provide physical insight into the development and interpretation of spaceborne precipitation measurements - Reference

Constant false-alarm rate algorithm based on test cell information

A new constant false-alarm rate (CFAR) detection algorithm, designated as switching CFAR (S-CFAR), is proposed and analysed. The S-CFAR algorithm selects CFAR reference samples using the magnitude of the sample in the cell under test, which is an information that has not been exploited in any other existing CFAR detectors. S-CFAR closed-form analysis is presented, and comparisons with other representative CFAR algorithms are given. An S-CFAR detector can be tuned such that it has a small CFAR loss when operating on a homogeneous background while achieving improved robustness in the presence of interfering targets and clutter power transition. The S-CFAR detector is also simple to design and implement since no sample ordering is required. - Reference

Fundamental resolution limits of closely spaced random signals

Fundamental limitations on estimation accuracy are well known and include a variety of lower bounds including the celebrated Cramer-Rao lower bound. However, similar theoretical limitations on resolution have not yet been presented. The authors exploit results from detection theory for deriving fundamental limitations on resolution. In this correspondence the authors discuss the case of zero mean random Gaussian signals with a general and predefined covariance matrix observed with additive white Gaussian noise. The results are general and are not based on any specific resolution technique and therefore hold for any method and for any probability of successful resolution. The resolution limit is a simple expression of the observation interval, the pre-specified resolution success probability and the second derivative of the covariance matrix. As an example, the authors discuss the bearing resolution of two emitters with closely spaced direction of arrival, impinging on an array of sensors. The theoretical limits are compared with empirical performance of the model order selection criteria known as the Akaike information criterion and the minimum description length. - Reference

The Detection of Buried Pipes From Time-of-Flight Radar Data

Ultrawideband radar is commonly used in the frequency range of 50–500 MHz to detect buried pipes at a depth of about 1–2 m depending on the soil characteristics. The typical feature used to locate the pipes is the hyperbolic pattern of the time of flight generated by a linear scan of the antenna above the surface. When the pipes are close together, the hyperbolas overlap, and a straightforward least squares fit is not possible. The Hough transform provides one possible solution. This paper extends the Hough transform by introducing a weighting factor depending on the differentials of the unknown parameters with respect to the experimental errors, namely, the probe position error and the time-of-flight error. This enables optimally placed sets of data pairs to be given greater weight than “ill-conditioned” sets, as for example when all data pairs lie near one end of the arc. The result is a decrease in the background amplitude with respect to the maximum of the peaks in the Hough accumulator space. It is shown that this improvement persists even when many arcs are present. A mathematical analysis with analytical results is given for the case of four unknowns: pipe radius $R$ , pipe center position ($Y$, $Z$), and soil propagation velocity $V$. The results are presented through simulations introducing controlled uncertainties in the probe position, the time of flight, and its bin size. The simulations demonstrate the correlations that occur between the radius, depth, and velocity for given experimental uncertainties. - Reference

Three-Dimensional Motion Estimation of Atmospheric Layers From Image Sequences

In this paper, we address the problem of estimating 3-D motions of a stratified atmosphere from satellite image sequences. The analysis of 3-D atmospheric fluid flows associated with incomplete observation of atmospheric layers due to the sparsity of cloud systems is very difficult. This makes the estimation of dense atmospheric motion field from satellite image sequences very difficult. The recovery of the vertical component of fluid motion from a monocular sequence of image observations is a very challenging problem for which no solution exists in the literature. Based on a physically sound vertical decomposition of the atmosphere into cloud layers of different altitudes, we propose here a dense motion estimator dedicated to the extraction of 3-D wind fields characterizing the dynamics of a layered atmosphere. Wind estimation is performed over the complete 3-D space, using a multilayer model describing a stack of dynamic horizontal layers of evolving thickness, interacting at their boundaries via vertical winds. The efficiency of our approach is demonstrated on synthetic and real sequences. - Reference

A Two-Dimensional Spectrum Model for General Bistatic SAR

This paper derives a 2-D spectrum model for general bistatic synthetic aperture radar (SAR). By introducing some new parameters such as equivalent monostatic parameters, bistatic factor, and weighted-equivalent range, the 2-D spectrum of general bistatic SAR can be expressed in the form of monostatic SAR even when the transmitter and receiver move along unparallel trajectories with different velocities. The result formulates bistatic SAR into an equivalent monostatic SAR model and would be useful for developing efficient bistatic SAR algorithms in frequency-domain or hybrid-domain processing. Simulation results are given to validate the performance of the model. For special bistatic SAR configurations, the model can be simplified. Compared to other similar models, the proposed model is clearer and much more concise. - Reference

Information Theory-Based Approach for Contrast Analysis in Polarimetric and/or Interferometric SAR Images

We propose a new approach for evaluating the contribution of the different channels of polarimetric and interferometric synthetic aperture radar (PolInSAR) images. For that purpose, we demonstrate that the Bhattacharyya distance between the probability density functions of neighboring regions in the image provides an efficient scalar contrast measure. We show that the analysis of this contrast measure allows one to precisely characterize the contribution of each channel for different system configurations, including intensity, polarimetric, and interferometric images. We illustrate this approach using a real synthetic aperture radar image to compare several polarimetric system architectures. Since PolInSAR imaging configurations can correspond to complex and expensive systems, the proposed method can be helpful in system imaging optimization. - Reference

Sequential Along-Track Integration for Early Detection of Moving Targets

This paper concerns the joint multiframe sequential target detection and track estimation in early-warning radar surveillance systems. The rationale for applying sequential procedures in such a scenario is that they promise a sensitivity increase of the sensor or, alternatively, a reduction in the time needed to take a decision. Unlike previous works on sequential radar detection, the attention is not restricted to stationary targets, namely position changes during the illumination period are allowed. Starting from previous sequential rules, different truncated sequential strategies are proposed and assessed: they are aimed at orienting the sensor resources towards either the detection or the track estimation or the position estimation. Bounds on the performances of the proposed procedures in terms of the system parameters are derived and computational complexity is examined. Also, numerical experiments are provided to elicit the interplay between sensor-target parameters and system performances, and to quantify the gain with respect to other fixed-sample-size procedures. - Reference

Signal Synthesis and Receiver Design for MIMO Radar Imaging

Multiple-input–multiple-output (MIMO) radar is an emerging technology that has significant potential for advancing the state-of-the-art of modern radar. When orthogonal waveforms are transmitted, with $M+N$ ($N$ transmit and $M$ receive) antennas, an $MN$-element filled virtual array can be obtained. To successfully utilize such an array for high-resolution MIMO radar imaging, constant-modulus transmit signal synthesis and optimal receive filter design play critical roles. We present in this paper a computationally attractive cyclic optimization algorithm for the synthesis of constant-modulus transmit signals with good auto- and cross-correlation properties. Then we go on to discuss the use of an instrumental variables approach to design receive filters that can be used to minimize the impact of scatterers in nearby range bins on the received signals from the range bin of interest (the so-called range compression problem). Finally, we present a number of numerical examples to demonstrate the effectiveness of the proposed approaches.- Reference

Maximum Position Alignment Method for Noisy High-Resolution Radar Target Classification

In this paper, the alignment of noisy high-resolution radar signals using the maximum position method is studied. The relationship between the shift estimation and the signal-to-noise ratio is considered. As a result, two analytical expressions are obtained that approximate the root-mean-square error of the difference in the shift estimation with and without noise. These two expressions allow us to improve the understanding of the sensitivity to noise of the Maximum Position alignment method. - Reference

Imaging Simulation of Bistatic Synthetic Aperture Radar and Its Polarimetric Analysis

Employing the 3-D mapping and projection algorithm (MPA), an imaging simulation of bistatic synthetic aperture radar (BISAR) observation over a complex scenario is developed. Based on the explicit expression of the point target response of stripmap BISAR imaging, raw data are efficiently generated from the scattering map precalculated by MPA. Some examples of BISAR image simulation are studied. The polarimetric characteristics of a BISAR image are then discussed. It is found that some typical polarimetric parameters such as Cloude's $alpha$, $beta$, and $gamma$ might become unable to describe the scattering mechanism under bistatic observation. A transform of unified bistatic polar bases for a BISAR image is proposed. The parameters $\alpha$, $\beta$ , and $\gamma$ are modified to retain the property of orientation independence in the bistatic circumstance. Analysis of simulated images shows that the redefined $\alpha$, $\beta$ , and $\gamma$ after the unified bistatic polar bases transform well describe different scattering mechanisms in BISAR imaging. It provides a primary tool for BISAR image interpretation and terrain classification. Reference

Whitening Dual-Polarized Weather Radar Signals With a Hermitian Transformation

Oversampling weather radar signals in range and then whitening these signals has been shown to improve the accuracy of spectral moments. For dual-polarized radar, the polarimetric variables depend upon information gleaned from the cross correlation of the different received signals. Theoretical improvements to the polarimetric variables have been provided to date, but experimental evidence of improvements through whitening has been limited. This paper provides an analysis of the effects of whitening on the estimated cross correlation along with experimental results of whitening applied to polarimetric variables. Different whitening transformations based solely on covariance matrix inversions will be shown to affect the copolar correlation of the whitened data. A Hermitian symmetric whitening transformation will be shown to produce better estimates of polarimetric variables obtained from whitened data than the original whitening transformation defined for use with range oversampling.Reference

Thursday, September 25, 2008

Holographic Research to Enhance Aircraft Antennas

The US Air Force has funded researchers at HRL Laboratories in Malibu, California to work on innovative new holographic techniques to create antennas that do not detract from an aircrafts aerodynamics.

The team are working on holographic impedance surfaces that will make antennas completely flush with the surface of the aircraft while still maintaining or even enhancing current protruding antenna capabilities.

The team are building the surfaces out of metallic materials on a substrate.

Programme manager at the Air Force Office of Scientific Research, Dr Arje Nachman said that the technology offers several benefits.

"One attractive benefit offered by these interesting surfaces is that if the tail of an aircraft obstructs the beam of an antenna then the tail can be covered by a suitably crafted impedance surface in such a way that the antenna beam flows around the tail as if the tail weren't there," Nachman said.

The HRL team is now trying to extend the capabilities of the electromagnetic impedance and experiment with practical implementations of it.

The researchers plan to create new kinds of unit cells and are also seeking new mapping techniques that allow those cells to be positioned over complex objects.

By Daniel Garrun.

Thursday, August 28, 2008

Взлет "Беркута". К 100-летию со дня рождения академика А.А. Расплетина

Академик Александр Андреевич Расплетин Есть люди, яркая творческая жизнь и трудовые свершения которых, словно верстовые вехи, на многие годы предопределяют стратегическое направление развития целых трудовых коллективов и даже отраслей производства. Их имена золотыми буквами вписаны в историю страны. Именно таким человеком был академик Александр Андреевич Расплетин. 25 августа 2008 года исполняется 100 лет со дня рождения этого крупного ученого в области радиотехники и телевидения, талантливого инженера и организатора, одного из основоположников советской (российской) инженерной школы разработки и создания систем зенитного управляемого ракетного оружия. А также одного из основателей НПО "Алмаз" (ранее КБ-1), ныне Головного системного конструкторского бюро Концерна ПВО "Алмаз-Антей", которое носит его имя.

Когда в далеком 1956 году в Советском Союзе была принята на вооружение зенитная ракетная система С-25 "Беркут", создание и разработка которой явились настоящим научно-техническим прорывом, это стало подобно сенсации. Никто в мире ничего похожего тогда не создавал. А появилась такая ЗРС в КБ-1 (потом НПО "Алмаз" имени академика А.А. Расплетина, ОАО "ГСКБ "Алмаз-Антей"). У истоков ее создания стоял Александр Андреевич Расплетин - Герой Социалистического Труда, лауреат Ленинской и Государственной премий СССР.

Radar tower and radome

Radar tower and radome

Radar Tower (formerly FPS-107) - Alsask, Saskatchewan Canada. All other Admin structures and Height Finder towers have been razed.

Photo: Northern Pike

Wednesday, August 27, 2008

Polarization isolation requirements for linear dual-polarization weather Radar in simultaneous transmission mode of operation

Yanting Wang; Chandrasekar, V., "Polarization isolation requirements for linear dual-polarization weather Radar in simultaneous transmission mode of operation," IEEE Transactions on Geoscience and Remote Sensing, vol.44, no.8, pp.2019 - 2028, Aug. 2006. doi: 10.1109/TGRS.2006.872138

Abstract: A dual-polarization radar system operating in simultaneous transmission mode of both horizontal and vertical polarization states is a viable implementation if only copolar measurements are needed. The simultaneous transmission of horizontal and vertical polarizations results in an arbitrary elliptical polarization state transmitted, whereas the reception states in horizontal and vertical polarizations are neither copolar nor cross-polar to the transmitted state. Because of this, it is often referred as the hybrid mode. Previous studies have shown that the hybrid mode in the linear horizontal and vertical polarization basis is capable of providing measurements similar to the alternate transmission mode for most measurement conditions. These findings are based on the assumption of perfect sensing systems. This paper presents the results of radar system limitations on hybrid mode measurements that in turn are converted to system requirements. It is shown that the polarization purity requirement is more stringent for the hybrid mode compared to the alternate mode of operation

URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1661791&isnumber=34774

Tuesday, January 15, 2008

Two Weather Radars...

Precipitation intencity

At this picture, captured from the Buienradar.nl real-time dynamic visualization, you can see the precipitating area above the Netherlands and North Sea (January 15, 2008). As soon as the cloud layer and precipitations have been quite homogenous, the symmetrical figures at this picture show, actually, the antenna patterns of two weather radars - in De Bilt (at the center of lower circuit) and in Den Helder (at the center of upper circuit).

Friday, January 11, 2008

Microwave Journal

Microwave Journal Online

Phased-array Radars: Past, Astounding Breakthroughs and Future Trends

Brookner, E., 2008: Phased-array Radars: Past, Astounding Breakthroughs and Future Trends, Microwave Journal, 51(1) - pp. 30

In-depth look at the advanced development and proliferation of phased-array radars over the last five decades...

On-line version

FGAN/FHR

FGAN/FHR (Forschungsgesellschaft für Angewandte Naturwissenschaften/ Forschungsinstitut für Hochfrequenzphysik und Radartechnik - Defense Research Facility for Applied Science/Research, Institute for High-frequency Physics and Radar Techniques), Wachtberg near Bonn, Germany.

Official site

PAMIR (Phased Array Multifunctional Imaging Radar)

PAMIR is an airborne SAR/MTI (Synthetic Aperture Radar/Moving Target Indication) experimental instrument of FGAN/FHR. The multifunctional PAMIR instrument is of AER (Airborne Experimental Radar) and AER-II heritage, both of FGAN/FHR. more...

Wednesday, January 9, 2008

"Зоопарк-1" (1Л219М)

http://www.arms-expo.ru/site.xp/049056048049124052051053.html

http://www.idelf.ru/site.xp/053054.html?month=11&year=2007

http://talks.guns.ru/forummessage/42/135080-2.html

Американский хайтек: подтверждается кража идеи телефона Беллом

Как сообщает Associated Press, американский журналист Сет Шульман (Seth Shulman) в выходящей 7 января 2008 года в свет книге "The Telephone Gambit: Chasing Alexander Graham Bell's Secret" утверждает, что Александр Грэхем Белл выкрал идею телефона у своего конкурента - Элиши Грея (Elisha Gray). Сомнения в первенстве Александра Белла - агрессивного юриста и патентного эксперта с сомнительной репутацией – высказывались и раньше. По мнению автора книги, окончательным подтверждением этого являетс… полный текст

Источник: CNews

ОАО «НИИ «Стрела»

ОАО «НИИ «Стрела», входящее в концерн ПВО «Алмаз-Антей», - единственное предприятие в России, которое специализируется на разработке радиолокационной техники, предназначенной для наблюдения за наземными и надводными движущимися целями. Крупнейшие его заказчики - Министерство обороны РФ, Пограничная служба ФСБ России, МВД, Государственный таможенный комитет, Министерство атомной энергетики. Многие разработанные институтом изделия до сих пор не имеют мировых аналогов. Коллектив института, который возглавляет Николай Зайцев, отметил 50-летие со дня своего образования.

Ровно полвека назад постановлением Совета Министров СССР на тульском заводе «Арсенал» было создано особое конструкторское бюро № 668, предназначенное вначале для сопровождения в производстве и модернизации радиолокационных станций наземной артиллерийской разведки (типа CHAP). Полностью самостоятельными разработками ОКБ занялось с 1957 года. Уже первые из них - РЛС «Тобол» для всемирно известной зенитной установки «Шилка», станции СНАР-2А, СНАР-6, система топопривязки боевых порядков артиллерии «Береза» - сделали предприятию имя.

Номенклатура работ, а также численность ОКБ стремительно росли. Не случайно приказом министра радиопромышленности в 1961 году предприятие было переведено в группу проектных организаций, непосредственно подчиненных министерству.

К середине 60-х сформировалась тематика предприятия. Она включала

  • мобильные РЛС наземной артиллерийской разведки типа «CHAP»,
  • переносные РЛС ближней и малой дальности действия,
  • радиолокационные комплексы разведки огневых позиций противника и корректировки огня собственных средств,
  • радиоприборные комплексы систем активной защиты танков,
  • радиолокационные прицелы для противотанковых пушек и ракет,
  • радиоэлектронные системы управления ПТУРС, в том числе и выстреливаемых из ствола пушки.

С начала 80-х годов предприятие приступило к разработке радиолокационных средств охраны границы в интересах Пограничных войск.

Расширение и усложнение тематики, по которой предприятие завоевывало лидирующие позиции в стране, привело в 1979 году к преобразованию ОКБ в научно-исследовательский институт «Стрела». Большой вклад в развитие предприятия, повышение его статуса принадлежит Симачеву Вячеславу Ивановичу – начальнику ОКБ с 1959 г., а затем директору и главному конструктору НИИ «Стрела» с 1979 г., лауреату Ленинской премии, доктору технических наук, и команде его единомышленников.

За годы своей деятельности коллективом института были разработаны и поставлены на вооружение нашей армии свыше 30 образцов военной техники, многие из которых уникальны по своим тактико-техническим характеристикам. Это

  • семейство РЛС CHAP - CHAP-2A, СНАР-6, СНАР-10, СНАР-15;
  • мобильные комплексы разведки наземных и надводных целей «Голотурия», «Голотурия – 88»;
  • малогабаритные переносные РЛС «Фара» и «Фара-1», допускающие возможность их использования в качестве прицела для стрелкового оружия;
  • переносные РЛС «Гарпун», «Кредо», «Кредо-1»;
  • радиолокационные комплексы разведки огневых позиций «АРК-1», «АРК-1М», «Зоопарк-1»;
  • радиоэлектронные системы управления для комплексов ПТУРС «Дракон», «Кобра», «Штурм-В», «Штурм-С», «Агона»;
  • радиолокационный приборный комплекс для комплекса активной защиты танков «Дрозд»;
  • радиолокационный прицел для противотанковой пушки «Рута»,
  • подвижной пункт разведки и управления тактической ПВО «Овод»

и многие другие.

В созданных изделиях реализованы самые передовые технические решения, на которые специалисты НИИ «Стрела» получили более 600 авторских свидетельств на изобретения и патентов. За высокие достижения свыше 150 сотрудников института награждены государственными наградами СССР и Российской Федерации, наиболее выдающиеся работы (свыше 10) удостоены Государственной и Ленинской премий.

В начале 2002 года государственное предприятие НИИ «Стрела» в соответствии с указом Президента РФ было преобразовано в акционерное общество открытого типа и вошло в состав крупнейшего в России оборонно-промышленного холдинга «Концерн ПВО «Алмаз-Антей». Руководство концерна оказывает необходимую помощь институту в решении корпоративных вопросов управления предприятием, в формировании перспективных программ развития, а также в осуществлении единой технической политики.

В последние годы институтом разработаны и поставляются новейшие образцы вооружения и военной техники (ВВТ), отвечающие самым современным требованиям и не уступающие лучшим мировым аналогам. К ним относятся высокоинформативные радиолокационные средства, такие как

  • «Кредо-М1»,
  • «Гамма-ПВ»,
  • «Фара-ПВ»,
  • унифицированная артиллерийская баллистическая станция «Рампа»,
  • модернизированная РЛС СНАР-10М («Пантера»),
  • модернизированный комплекс «Зоопарк-1».

В частности, многоканальный радиолокационный комплекс «Зоопарк-1» (индекс после модернизации 1Л219М), предназначен для определения координат огневых позиций противника (минометов, артиллерии, РСЗО и ТР) по выстрелу (пуску) и корректировки огня собственных средств. Комплекс полностью автоматизирован, что обеспечивает его быстрое развертывание и выдачу сообщений о координатах сразу нескольких разведданных огневых позиций в артиллерийские подразделения в течение не более 20 секунд с момента залпа противника.

Разработанные в ОАО «НИИ «Стрела» радиолокационные и радиолокационно-оптические средства позволяют различным силовым службам и ведомствам эффективно и качественно в любых погодных условиях и в любое время суток решать задачи контроля перемещения объектов и протяженных территорий как в автономном режиме, так и в составе автоматизированных систем управления и сбора информации.

За разработку и поставку новых образцов ВВТ более 20 ведущих специалистов предприятия в 2003 году награждены орденами, медалями, им присвоены почетные звания Российской Федерации, в их числе – заместитель генерального директора по производству В. Кузьмин, заместитель главного инженера по научно-техническому обеспечению разработок С. Савушкин, заместитель главного конструктора В. Потапов, главный технолог предприятия Е. Куперман.

Главное богатство предприятия конечно же люди. Руководство НИИ «Стрела» многое делает для их социальной защиты. С начала 2001 года в институте нет задолженности по зарплате, которая выплачивается вовремя. Немаловажно и то, что за последние три года средняя зарплата по институту выросла в 3 раза. Социальная сфера деятельности коллектива регулируется коллективным договором и предусматривает расходы на медицинское обслуживание, в том числе приобретение путевок, проведение культурно-массовой и спортивно-оздоровительной работы, доплату к пособию по уходу за ребенком, оказание материальной помощи.

К началу этого года объем продукции предприятия, в основном за счет выполнения гособоронзаказа, увеличился по сравнению с 2000 годом более чем в 4 раза, а по поставкам серийной продукции - в 7,5 раза. В 2004 году планируется увеличить объем выпускаемой продукции не менее чем на 15 процентов, провести дальнейшее повышение зарплаты работников института. Уже сейчас средняя зарплата по НИИ превышает среднегородскую и является одной из самых высоких среди группы промышленных предприятий Тулы.

В институте разработана и реализуется программа развития, которая включает в себя техническое перевооружение, создание научно-технического задела, подготовку квалифицированных кадров.
Кадры, как известно, по-прежнему решают все. Сегодня на предприятии - стабильный работоспособный коллектив. Особую заботу в институте проявляют о подготовке квалифицированных молодых специалистов непосредственно в НИИ «Стрела» на филиалах 3 кафедр Тульского государственного университета (ТГУ), где преподавание ведут ведущие сотрудники НИИ. Подготовка научных кадров высшей квалификации проводится в рамках договоров о научно-техническом сотрудничестве с Тульским артиллерийским инженерным институтом и ТГУ.

На техническое перевооружение и создание научно-технического задела с согласия совета директоров ОАО «НИИ «Стрела» привлекается часть прибыли. В 2003 г. за счет собственных средств финансировалось семь НИОКР. Институтом разработана концепция развития радиоэлектронных средств в области своей специализации и предложены заказчикам проекты программ работ на ближайшую и дальнюю перспективу.

Встречая свое 50-летие, коллектив НИИ «Стрела» с уверенностью смотрит в завтрашний день.


Адрес: 300002, Тула, ул.М. Горького, 6  E-mail: strela at tula dot net


Источник: газета «Красная звезда»