Millimeter-Wave Radars for Environmental Studies

Vavriv, D. M.; Volkov, V. A.; Bormotov, V. N.; Vynogradov, V. V.; Kozhyn, R. V.; Trush, B. V.; Belikov, A. A.; Semenyuta, V. Ye.

doi:10.1615/telecomradeng.v61.i4.30

Cited by 10 publications

(5 citation statements)

References 15 publications

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“…For weather radars, the well-defined reflectivity of calibration spheres on tethered balloons or erected trihedral corner reflectors has been a reliable external reference for years (Atlas, 2002). In more recent years, this technique is being extended to scanning, ground-based millimeter-wave radars (Vega et al, 2012;Chandrasekar et al, 2015). For the airborne perspective on the other hand, the direct fly-over and the subsequent removal of additional background clutter is difficult to reproduce (Z.…”

Section: Introductionmentioning

confidence: 99%

Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars

et al. 2019

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Abstract. This study gives a summary of lessons learned during the absolute calibration of the airborne, high-power Ka-band cloud radar HAMP MIRA on board the German research aircraft HALO. The first part covers the internal calibration of the instrument where individual instrument components are characterized in the laboratory. In the second part, the internal calibration is validated with external reference sources like the ocean surface backscatter and different air- and spaceborne cloud radar instruments. A key component of this work was the characterization of the spectral response and the transfer function of the receiver. In a wide dynamic range of 70 dB, the receiver response turned out to be very linear (residual 0.05 dB). Using different attenuator settings, it covers a wide input range from −105 to −5 dBm. This characterization gave valuable new insights into the receiver sensitivity and additional attenuations which led to a major improvement of the absolute calibration. The comparison of the measured and the previously estimated total receiver noise power (−95.3 vs. −98.2 dBm) revealed an underestimation of 2.9 dB. This underestimation could be traced back to a larger receiver noise bandwidth of 7.5 MHz (instead of 5 MHz) and a slightly higher noise figure (1.1 dB). Measurements confirmed the previously assumed antenna gain (50.0 dBi) with no obvious asymmetries or increased side lobes. The calibration used for previous campaigns, however, did not account for a 1.5 dB two-way attenuation by additional waveguides in the airplane installation. Laboratory measurements also revealed a 2 dB higher two-way attenuation by the belly pod caused by small deviations during manufacturing. In total, effective reflectivities measured during previous campaigns had to be corrected by +7.6 dB. To validate this internal calibration, the well-defined ocean surface backscatter was used as a calibration reference. With the new absolute calibration, the ocean surface backscatter measured by HAMP MIRA agrees very well (<1 dB) with modeled values and values measured by the GPM satellite. As a further cross-check, flight experiments over Europe and the tropical North Atlantic were conducted. To that end, a joint flight of HALO and the French Falcon 20 aircraft, which was equipped with the RASTA cloud radar at 94 GHz and an underflight of the spaceborne CloudSat at 94 GHz were performed. The intercomparison revealed lower reflectivities (−1.4 dB) for RASTA but slightly higher reflectivities (+1.0 dB) for CloudSat. With effective reflectivities between RASTA and CloudSat and the good agreement with GPM, the accuracy of the absolute calibration is estimated to be around 1 dB.

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Section: Introductionmentioning

confidence: 99%

Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars

et al. 2019

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“…Наукові і конструкторські колективи України зробили важливий внесок у створення космічної бази СРСР та виконання союзних космічних програм (див. огляди у роботах [32,38]). У той час космічні дослідження в Україні велися за такими напрямками:…”

Section: коротка характеристика рівня розвитку космічних досліджень в...unclassified

“…Урядом США вже виділено для їхнього проведення 349 000 доларів. США готові також приступити до спільної розробки і використання багатоцільової системи екологічного контролю на основі розроблених ІРЕ АН України радіолокаторів бічного огляду, вимірників р озсіювання та радіолокаторів з синтезованою апаратурою [37,38] (у нас в країні ця система називається «Янтар Еко»).…”

Section: участь україни в роботі міжнародних організацій і програмunclassified

From the history of space research in Ukraine. 1. The performance of space research as of 1991 year

Yatskiv¹

2022

Kosm. nauka tehnol.

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The article displays the material of 1991 from the author’s archive, which is devoted to the problems of space research arrangement and the space industry authority in independent Ukraine. A brief description of the space research level in Ukraine at that time is given. The active participation of Ukraine in the activity of international organizations and the implementation of USSR space programs are highlighted. The significant achievements and acquirements of scientific and design teams in the space research branch are emphasized. Among them, there were the rocket design center DB “Pivdenne” (now — Yangel Yuzhnoye State Design Office), E. O. Paton Electric Welding Institute of NAS of Ukraine, and many other enterprises and scientific institutions in Ukraine. In new conditions, under the newly acquired independence, the formidable task of preserving the aerospace industry of Ukraine arose. Within this task, it was necessary to preserve scientific and developing potential and to provide perspectives for scientific and technical progress. All this was possible only within the framework of the concept that had to be developed and which would contain the main goals of the national politics of Ukraine as an independent state in the branch of exploration and exploitation of space. It was necessary to create the aerospace agency of Ukraine for the coordination of space programs and to develop a law to regulate its activities. One more task was to adopt the state program of space exploration by the Verkhovna Rada, the program, which had to provide for the progress of fundamental and applied space research.

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“…The spectrum noise flow achieved is as low as -40 dB. The data acquisition system was similar to those developed for meteorological radars manufactured at the Institute of Radio Astronomy of the National Academy of Science of Ukraine [3].…”

Section: Characteristics Of the T/r Modulementioning

confidence: 99%

A compact, Ka-band magnetron based T/R module

Volkov

Vavriv

Kozhin

et al. 2006

2006 European Radar Conference

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This paper presents design and characteristics of a compact, highly integrated Ka-band T/R module built by using a miniature magnetron in the transmitter chain. By implementing a solid-state modulator and microstrip design in the microwave part of the receiver, the overall size of the module has been reduced significantly. The module provides capabilities to realize Doppler date processing by using a digital coherent-on-receiver technique.

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Millimeter-Wave Radars for Environmental Studies

Cited by 10 publications

References 15 publications

Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars

Calibration of a 35 GHz airborne cloud radar: lessons learned and intercomparisons with 94 GHz cloud radars

From the history of space research in Ukraine. 1. The performance of space research as of 1991 year

A compact, Ka-band magnetron based T/R module

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