Denormalization of visibilities for in-orbit calibration of interferometric radiometers

Torres, F.; Corbella, I.; Camps, A.; Duffo, N.; Vall-llossera, M.; Beraza, S.; Martín-Neira, Manuel

doi:10.1109/igarss.2005.1526033

Cited by 9 publications

(19 citation statements)

References 9 publications

(9 reference statements)

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“…10. These results are compatible with the characterization performed at subsystem level [16]. Considering that the average gain and offset are about 1 mV/K and −1700 mV (see Fig.…”

Section: B Resultssupporting

confidence: 78%

“…The variation of the phase of the correlator gain G kj with respect to temperature was found to be much more complex than initially found in [16]. For two receivers sharing the same local oscillator, this phase roughly follows the average physical temperature of the two receivers involved, as expected.…”

Section: B Resultsmentioning

confidence: 62%

“…The thermal characterization follows the methodology proposed in [16]. All PMS gains and offsets are characterized by sensitivity coefficients derived by linear fit from measurements in a limited temperature range around the operational point.…”

Section: A Approach For Thermal Characterizationmentioning

confidence: 99%

“…The result is used in the second step as input for processing to a higher level, involving the correction of the quadrature error and comparator offset, obtaining, as result, the quadraturecorrected normalized correlation M kj [9], [15]. The calibrated visibility (level 1A) is computed in the next step after denormalization using the system temperatures calibrated with a four-point two-level noise injection [9], [16]. This calibrated visibility is used as input for the image reconstruction process, resulting in the brightness temperature at the antenna reference plane (level 1B).…”

Section: B Softwarementioning

confidence: 99%

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On-Ground Characterization of the SMOS Payload

Corbella

Torres

Duffo

et al. 2009

IEEE Trans. Geosci. Remote Sensing

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Abstract-The on-ground characterization of the synthetic aperture radiometer onboard the Soil Moisture and Ocean Salinity mission is described. Characterization includes basic functionality, internal calibration, thermal cycling, response to point and flat sources, self-radio-frequency interference, and others. The description of the different tests performed as well as the detailed results are provided. The results show that the instrument is very stable and has all gains and offsets consistent with the ones obtained at subsystem level. On the other hand, the phase of the visibility has a larger variation with temperature than expected, a small signal leakage from the local oscillators is present, and a small interference from the X-band transmitter during short periods of time has been detected. The implementation of internal-calibration procedures, along with the accurate thermal characterization performed, have been used to produce highly accurate brightness-temperature values well within specifications.Index Terms-Calibration and characterization, interferometric aperture synthesis, microwave radiometry.

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“…10. These results are compatible with the characterization performed at subsystem level [16]. Considering that the average gain and offset are about 1 mV/K and −1700 mV (see Fig.…”

Section: B Resultssupporting

confidence: 78%

Section: B Resultsmentioning

confidence: 62%

Section: A Approach For Thermal Characterizationmentioning

confidence: 99%

Section: B Softwarementioning

confidence: 99%

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On-Ground Characterization of the SMOS Payload

Corbella

Torres

Duffo

et al. 2009

IEEE Trans. Geosci. Remote Sensing

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“…This technique is known as the four-point method, and allows us to compute the PMS gains and offsets as [16]:…”

Section: Pms Calibrationmentioning

confidence: 99%

Microwave Imaging Radiometers by Aperture Synthesis Performance Simulator (Part 2): Instrument Modeling, Calibration, and Image Reconstruction Algorithms

et al. 2016

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Abstract:The Synthetic Aperture Interferometric Radiometer Performance Simulator (SAIRPS) has been a three-year project sponsored by the European Space Agency (ESA) to develop a completely generic end-to-end performance simulator of arbitrary synthetic aperture interferometric radiometers. In a companion manuscript (Part I), the Radiative Transfer Module used to generate synthetic fully polarimetric brightness temperatures from 1 to 100 GHz, including land and ocean covers, as well as the atmosphere, is described in detail. In this manuscript (Part II), the instrument model, the calibration procedure, and the imaging algorithms are described. The instrument model includes the simulation of the array topology in terms of the number of antenna elements, the time-dependent position and orientation, and the arbitrary receivers' topology which can be modified from a very generic one by connecting and disconnecting subsystems. All the parameters can be, one by one, defined either by mathematical functions or by input data files, including the frequency and temperature dependence. Generic calibration algorithms including an external point source, the flat target transformation, and the two-level correlated noise injection are described. Finally, different image reconstruction algorithms suitable for arbitrary array topologies have also been implemented and tested. Simulation results have been validated and selected results are presented.

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MIRAS-SMOS Demonstrator Test Campaigns at Polytechnic University of Catalonia

Beraza

González

Torres

et al. 2006

2006 IEEE International Symposium on Geoscience and Remote Sensing

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SMOS, acronym for Soil Moisture and Ocean Salinity, is the second selected opportunity mission on "The Living Planet Program: Earth Explorer Opportunity Missions" of the European Space Agency (ESA) [1]. The MIRAS (Microwave Imaging Radiometer with Aperture Synthesis) is the single SMOS payload, which is compounded of 69 L-band receivers to form a Y shape interferometer with full on-board calibration capability. The Spanish company EADS-CASA is currently leading the development of a Small scale Airborne prototype of the MIRAS (SAM), in the frame of the MDPP-3 project (MIRAS Demonstrator Pilot Project, stage 3 ) sponsored by the ESA. Several European institutions, including the Polytechnic University of Catalonia, are participating in the development of the MDPP-3 instrument and test campaigns. The demonstrator consists of 12 receivers called LICEF (4 per arm), 1 reference radiometer (NIR) andincludes the same internal calibration system scheme foreseen for MIRAS. The instrument has been designed to be flown in the Skyvan of the LST/HUT (Laboratory of Space Technology, Helsinki University of Technology), where several airborne campaigns over land and sea will be undertaken in order to asses the capability of SMOS calibration and retrieval algorithms to provide soil moisture and ocean salinity.

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Denormalization of visibilities for in-orbit calibration of interferometric radiometers

Cited by 9 publications

References 9 publications

On-Ground Characterization of the SMOS Payload

On-Ground Characterization of the SMOS Payload

Microwave Imaging Radiometers by Aperture Synthesis Performance Simulator (Part 2): Instrument Modeling, Calibration, and Image Reconstruction Algorithms

MIRAS-SMOS Demonstrator Test Campaigns at Polytechnic University of Catalonia

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