Initial results of the GeoSTAR Prototype (Geosynchronous Synthetic Thinned Array Radiometer)

Tanner, Alan; Brown, Shannon; Dinardo, S. J.; Gaier, Todd; Kangaslahti, Pekka; Lambrigtsen, Bjorn; Wilson, William J.; Piepmeier, Jeffrey R.; Ruf, Christopher; Gross, S.M.; Lim, Boon; Musko, S.; Rogacki, S.

doi:10.1109/aero.2006.1655814

Cited by 16 publications

(11 citation statements)

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“…While low-Earth orbit (LEO) satellites provide coverage in relative narrow swaths and with a revisit time of 12-24 h, a geostationary Earth orbit satellite (GEO) can provide continuous hemispheric or regional coverage, which makes it possible to monitor highly dynamic phenomena such as hurricanes. Sponsored by the NASA Instrument Incubator Program, the Jet Propulsion Laboratory is currently developing a proof-ofconcept ground-based demonstrator, which has already produced very encouraging results [6].…”

Section: Analysis Of Array Distortion In a Microwavementioning

confidence: 99%

“…If the origin of coordinates is placed at the center of the array, and the staggered configuration of GeoSTAR is taken into account [6], the line coefficients are…”

Section: Radiometric Error Due To Arm Misalignmentmentioning

confidence: 99%

“…The elements are arranged in such a way that the three arm axes meet in an equilateral triangle. This is the so-called "staggered-Y" configuration, which is used to simplify the mechanical and electrical designs by eliminating the one odd center receiver [6].…”

Section: Radiometric Error Due To Arm Misalignmentmentioning

confidence: 99%

“…where T B is the brightness temperature, T rec is the receiver's physical temperature (assumed equal in all elements), F nk and F nj are the normalized antenna copolar voltage patterns, Ω k,j is the antenna's solid angle, r kj is the fringe-washing function ( r kj ∼ = 1 for GeoSTAR [6]), f 0 = c/λ is the center frequency, ξ = sin θ cos φ and η = sin θ sin φ are the direction cosines, and u kj and v kj are the antenna separation measured in wavelengths (baseline). The contribution of T rec to the visibility samples is negligible in the GeoSTAR prototype due to the low antenna coupling and the large antenna separation [9].…”

Section: Basics Of Geostarmentioning

confidence: 99%

“…2, top). The modified brightness temperature T M (ξ mn , η mn ) is computed by taking into account the theoretical antenna patterns of the Potter antennas used in the ground demonstrator [6]. To minimize the number of antennas required for a given spatial resolution, the u-v domain is undersampled: the real image is recovered at the center of the (ξ, η) plane, but six aliases of the image appear around it, which are centered at [9] (ξ cn , η cn ) = 2…”

Section: Basics Of Geostarmentioning

confidence: 99%

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Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Torres

Tanner

Brown

et al. 2007

IEEE Trans. Geosci. Remote Sensing

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Abstract-The Geostationary Synthetic Thinned Array Radiometer represents a promising new approach to microwave atmospheric sounding from geostationary orbit based on passive interferometry. Distortion due to mechanical or thermal constraints produces a displacement of the ideal antenna positions in the array that causes sampling errors. In this paper, the impact of array distortion on radiometric error is analyzed in detail so as to identify the dominant sources of error. A preliminary analysis showing that array distortion can be well corrected by means of an external phase reference is also presented.

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Section: Analysis Of Array Distortion In a Microwavementioning

confidence: 99%

“…If the origin of coordinates is placed at the center of the array, and the staggered configuration of GeoSTAR is taken into account [6], the line coefficients are…”

Section: Radiometric Error Due To Arm Misalignmentmentioning

confidence: 99%

Section: Radiometric Error Due To Arm Misalignmentmentioning

confidence: 99%

Section: Basics Of Geostarmentioning

confidence: 99%

Section: Basics Of Geostarmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Torres

Tanner

Brown

et al. 2007

IEEE Trans. Geosci. Remote Sensing

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Investigating the potential benefit to a mesoscale NWP model of a microwave sounder on board a geostationary satellite

Duruisseau

Chambon

Guedj

et al. 2017

Quart J Royal Meteoro Soc

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Observing the Earth with a microwave radiometer on board a geostationary satellite has generated interest for several decades. Such a mission would add a high observation rate in the microwave spectrum, offered by a geostationary orbit, to the sounding capabilities of the current observing system. The instrumental concept under study considers a microwave radiometer with six channels with different observation errors within the 183.31 GHz water vapour absorption band. Observing System Simulation Experiments (OSSEs) are conducted to examine if these very frequent microwave observations would be beneficial to mesoscale numerical weather prediction (NWP) and complement the current or soon‐available satellite observations. The OSSE framework is built up on (i) simulated observations from a known ‘truth’ which is a long and uninterrupted forecast from the Météo‐France ARPEGE global model, and (ii) the Météo‐France AROME mesoscale model in which the simulated observations are assimilated using a 1 h update cycle 3D‐Var data assimilation system. Benefits that may be expected from such a microwave sounder mission are evaluated in the context of a dense observing system including observations from the future hyper‐spectral InfraRed Sounder on board Meteosat Third Generation. In particular, impacts of microwave observations with observation errors ranging from 1.25 to 5 K are studied. One of the main findings of this study is that fine‐scale NWP systems do not only need observations that are frequent in space and time, but that these observations must be accurate as well.

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Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging

Zhao

et al. 2021

IEEE Access

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A Ka-band 1024-channel passive millimeter wave (PMMW) imager with 1 GHz bandwidth called BHU-1024 has been developed by Beihang University for security screening. BHU-1024 uses linear phased array to obtain resolution in the horizontal direction and uses aperture synthesis to obtain resolution in the vertical direction. The non-ideal characteristics of the hardware cause the decrease of system sensitivity and always blur the reconstructed image, hampering applications where high resolution and accurate recognition are emphasized. Hence, effective calibration is a prerequisite to ensure the quality of the millimeter wave image. In this paper, the overall calibration approach is presented, focusing on the main errors relevant to the BHU-1024 instrument design: The basic correlator counts are preprocessed to correct for comparators offset and quadrature error. The residual offset is estimated by continuously sweeping the local oscillator (LO) phase. And for the baseline error, a novel and effective calibration approach, which makes use of an external noise source mounted on the metal frame, is proposed to tackle this problem. The results of simulation and measurement demonstrate the validity of the overall calibration approach. Finally, the actual calibrated data is used to reconstruct the millimeter wave image, which further validates the calibration process. INDEX TERMS Calibration of visibility samples, hardware imperfections, passive millimeter wave imaging, security screeningThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

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Initial results of the GeoSTAR Prototype (Geosynchronous Synthetic Thinned Array Radiometer)

Cited by 16 publications

References 0 publications

Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Analysis of Array Distortion in a Microwave Interferometric Radiometer: Application to the GeoSTAR Project

Investigating the potential benefit to a mesoscale NWP model of a microwave sounder on board a geostationary satellite

Calibration of Visibility Samples for Real-Time Passive Millimeter Wave Imaging

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