• 한국전자파학회논문지
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• 제22권9호
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• pp.858-867
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• 2011

본 논문은 수면의 기름 유출 유무, 유출된 기름의 분포 및 확산에 관한 정보를 실시간 원격으로 수집할 수있는 마이크로파 라디오미터의 개발에 관한 연구 내용을 기술한다. 먼저 수면에 유출된 두께 0~4 mm 범위의 기름층을 0.2 mm 이내의 오차로 원격 측정이 가능한 마이크로파 라디오미터의 개발 목표 성능을 달성하기 위해 요구되는 목표 사양을 도출하였으며, 이를 토대로 라디오미터 수신기를 설계하였다. 설계된 수신기의 시스템 이득과 잡음 지수의 budget 분석을 통해 설계의 적절성을 점검하였으며, 이 결과를 활용하여 수신 주파수 10.65 GHz, 대역폭 58 MHz로 47.3 dB의 시스템 이득과 0.46 K 이내의 수신 감도를 갖는 고이득, 고감도 수신기를 제작하였다. 제작된 수신기와 표준 혼 안테나로 구성된 마이크로파 라디오미터로 실제 수면 유막을 대상으로 실험한 결과, 0.13 mm 이내의 오차로 0~5 mm 범위의 유막 두께를 측정하는데 성공하여 목표 성능이 만족함을 검증하였다.

• 한국전자파학회논문지
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• 제24권9호
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• pp.900-907
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• 2013

본 논문은 수면으로부터 복사되는 마이크로파 대역의 미약한 열잡음 전파를 수신하여 수면 표층수의 염분농도의 변화를 실시간으로 원격 모니터링이 가능한 L-band 마이크로파 라디오미터의 개발에 관한 연구 내용을 기술한다. 먼저 수면 염분 농도의 원격 측정 가능 범위 0~40 psu, 최대 오차 2 psu의 목표를 달성하기 위해 요구되는 마이크로파 라디오미터의 설계 사양을 도출하였으며, 도출된 사양을 만족시키는데 필요한 라디오미터 수신기를 설계 제작하였다. 제작된 수신기는 주파수 1,390 MHz, 대역폭 45 MHz로 47 dB의 시스템 이득과 0.41 K 이내의 감도를 갖는다. 제작된 수신기와 표준 혼 안테나로 구성한 L-band 마이크로파 라디오미터로 간이 풀장에 형성된 염분 농도 0~28 psu 범위의 수면을 대상으로 한 원격 측정 실험 결과, 10~28 psu 구간에서는 1.4 psu 이하로, 0~10 psu의 낮은 염분 농도 구간에는 2.9 psu의 오차로 수면 염분 농도의 변화를 측정할 수 있었다.

• 한국전자통신학회논문지
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• 제9권2호
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• pp.173-180
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• 2014

본 논문은 토양에서 복사되는 마이크로파 대역의 미약한 열잡음 전력을 수신하여 토양 수분 함유량의 변화를 실시간으로 원격모니터링이 가능한 L-Band 마이크로파 라디오미터를 설계하는 내용에 관하여 기술한다. 토양 수분 함유량 0%~50%의 측정범위와 최대 오차 2%의 목표 성능을 달성하기 위해 토양 수분함유량에 따른 토양의 복사특성을 연구 및 목표 사양을 도출하였으며, 이를 바탕으로 도출된 사양을 만족시키는 마이크로파 라디오미터의 수신기를 설계 및 제작하였다. 제작된 수신기는 주파수 1390MHz, 대역폭 40MHz으로 50dB의 시스템 이득과 1.54dB의 NF를 가지며, 최대 0.313K, 평균 0.19K의 수신감도를 갖는다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.526-529
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• 2005

Dual-channel Radiometers for Earth and Atmosphere Monitoring (DREAM) is the Korean first spaceborne microwave radiometer which is the main payload of Science and Technology SATellite-2 (STSAT-2). STSAT-2 will be launched by Korea Space Launch Vehicle-l (KSL V-I) at NARO Space Center in Korea in 2007. DREAM is a two-channel, total power microwave radiometer with the center frequencies of 23.8 GHz and 37 GHz. The spaceborne radiometer is composed of an antenna unit, a receiver unit, and a data acquisition/processing unit. The bandwidths of radiometer are 600 MHz at 23.8 GHz and 1000 MHz at 37 GHz. The integration time of two channels is 200 rns. The sensitivity of DREAM is less than 0.5 K. This paper presents the required performance and system design of DREAM in detail.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.26-28
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• 2008

Soil moisture plays an important role in the land-atmosphere energy balance because it governs the partitioning of energy through latent heat fluxes or evapotranspiration. From the numerous studies, it is evident that the L-band radiometer is a useful and effective tool to measure soil moisture. The objective of the study is to develop and to verify the soil moisture retrieval algorithms for the L-band radiometer system. Through the radiometer-observed brightness temperature, surface emissivity and reflectivity can be derived, and, hence, soil moisture. We collect field and L-band airborne radiometer data from washita92, SGP97 and SGP99 experiments to assist the development of the retrieval algorithms. Upon launching the satellite L-band radiometer such as ESA-sponsored SMOS (Soil Moisture and Ocean Salinity) mission, the developed algorithms may be used to study and monitor globe soil moisture change.

• 대기
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• 제20권3호
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• pp.229-238
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• 2010

The 1,000~500 hPa thickness and the $0^{\circ}C$ isotherm at 850 hPa have been used as the traditional predictors for wintertime precipitation-type forecasts. New approaches are taking on added significance as preexistence method of determination for wintertime precipitation-type exhibits more or less prevalent false alarms. Moreover thicknesses and thermodynamic profiles from ordinary upper-air observation were not adequate to monitor the atmospheric structure. In this regard, Microwave radiometric profiler microwave radiometer is useful in wintertime precipitation-type forecasts because radiometric measurements provide soundings at high temporal resolution. In this study, the determination and the predictability of wintertime precipitation-type were examined by using the calculated thicknesses, temperature of 850 hPa (T850) from a microwave radiometer, and surface observation at National Center for Intensive Observation of severe weather (NCIO) located at Haenam, Korea. The critical values for traditional predictors (thickness of 1000~500 hPa and T850) were evaluated and adjusted to Haenam region because snow rarely occurred with a 1000-500 hPa thickness > 5,300 m and T850 > $-10^{\circ}C$. Three thicknesses (e.g., 1,000~850, 1000~700, and 850~700 hPa thickness), T850, surface air temperature, and wet-bulb temperature were also evaluated as the additional predictors. A simple nomogram and a flow chart were finally designed to determine the wintertime precipitation-type using the microwave radiometer. The skill scores for the predictability of precipitation-type determination are considerably improved and the predictors showed the temporal variations in 12 hours before precipitation. We can monitor the hit and run snowfall in winter successful by realtime watch of the predictors, especially in commutes of big cities.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.598-603
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• 2002

We summarize the activities concerning to the space-borne microwave radiometer (RAD) calibration and validation (Cal/Val) in China. It is important to know in advance the brightness temperature of a given sea surface before external calibrating RAD due to its special characteristic of system. In the paper, we analyse some modeling results on sea surface emissivity and atmospheric transmissivity at different frequencies, and compare the calculated brightness temperatures with those measurements from some air-borne microwave radiometers. We also introduced the whole contents on RAD Val and developed two methods of retrieving sea surface winds. We compared the retrievals of wind speeds to those from NDBC buoys. At last, we introduce some plans of Cal/Val for testing our RAD.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.398-401
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• 2006

Dual channel Radiometer for Earth and Atmospheric Monitoring (DREAM) is the main payload on Science and Technology SATellite-2 (STSAT-2) of Korea. DREAM is two-channel microwave radiometer with linear polarization, and operating at center frequencies of 23.8 GHz and 37 GHz. An equation for DREAM calibration is derived which accounts for losses and re-radiation in the microwave components of the radiometer due to physical temperature. This paper describes the radiometric calibration equation to get antenna temperature ($T_A$) from the measured output data. At lower altitude, the measured deep space temperature is contaminated by middle atmosphere and earth radiation. In this paper, we presented the detail mathematical formulation to find the altitude up to which cold source brightness temperature is not affected by earth and middle atmosphere radiation. The DREAMPFM data is used to calculate the performance parameters (linearity, sensitivity, dynamic range, and etc.) of the system.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.604-609
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• 2002

The passive microwave remote sensing has progressed considerably in recent years. Important earth surface parameters are detected and monitored by airborne and space born radiometers. However the spatial resolution of real aperture measurements is constrained by the antenna aperture size available on orbiting platforms and on the ground. The inverse problem technique is researched in order to improve the spatial resolution of microwave scanning radiometer. We solve a two-dimensional (surface) temperature-imaging problem with a major intention to develop high-resolution methods. In this paper, the scenario for estimation of both radiometer point spread function (PSF) and target configuration is explained. The PSF of the radiometer is assumed to be unknown and estimated from the observations. The configuration and brightness temperature of targets are also estimated. To do this, we deal with the parametric modeling of observation scenario. The performance of developed algorithms is illustrated on two-dimensional experimental data obtained by the water vapor radiometer.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.115-120
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• 2005

A c-band microwave radiometer receiver for river mouth water temperature remote sensing was designed and implemented The developed receiver operated at 5.1GHz frequency with 70MHz bandwidth. It had high gain of 50dB and low noise figure of 2dB. Also we executed efficiency evaluation about detection capability of the receiver with noise source similar input signal. The experiment results showed that the c-band receiver successfully detected the antenna temperature range from 193K to 300K.