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VIERS-1 scatterometer model

Janssen, P.A.E.M. (author), Wallbrink, H. (author), Calkoen, C.J. (author), van Halsema, D. (author), Oost, W.A. (author), Snoeij, P. (author), TNO Fysisch en Elektronisch Laboratorium (author)

In this paper a description is given of a physically based theoretical ocean backscatter model (called the VIERS-1 model) for intermediate incidence angles, and a comparison of its performance against the CMOD4 empirical model is made. The VIERS-1 scatterometer algorithm is based on a two-scale composite surface model which includes both...

article 1998

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A summary of the VIERS-1 scatterometer model

Janssen, P.A.E.M. (author), Wallbrink, H. (author), Calkoen, C.J. (author), van Halsema, D. (author), Oost, W.A. (author), Snoeij, P. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The VIERS-1 (Verification and Interpretation ERS-1) project has resulted in a new algorithm for the interpretation of the wind scatterometer, based on a physical model of air/sea/radar interaction in which the radar backscatter is calculated from wind and wave conditions. The model is inverted to obtain the wind from the radar backscatter. For...

article 1998

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Improved relation between radar backscatter from the ocean surface and surface wind vector

Snoeij, P. (author), Janssen, P.A.E.M. (author), van Halsema, D. (author), Calkoen, C.J. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The simulated VIERS backscatter, obtained using the ECMWF wind and WAM wave fields, was compared with the backscatter as observed by the ERS1I satellite. The air-sea temperature difference was set to zero since neutral stability is the most common situation that occurs over the oceans. The period of interest was the 6th of November 1991 at l2.OO...

conference paper 1996

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C-band solid state dual polarization T/R modules for airborne SAR systems

Vermeulen, B.C.B. (author), Koomen, P.J. (author), Hoogeboom, P. (author), Snoeij, P. (author), Pouwels, H. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The use of distributed power in a, on a phased array antenna based, SAR system offers new possibilities for the system operation. As a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna, the PHARUS system has been constructed. The system is installed on a Cessna...

conference paper 1996

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First Results and Status of the PHARUS Phased Array Airborne SAR

Greidanus, H.S.F. (author), Hoogeboom, P. (author), Koomen, P.J. (author), Snoeij, P. (author), Pouwels, H. (author), IEEE - Institute of Electrical and Electronics Engineers (author)

PHARUS is an airborne fully polarimetric C band SAR. It uses a compact phased array antenna with electronic beam steering. Its design provides for a flexible and robust system concept, suited for operational use on small aircraft. PHARUS was developed in The Netherlands to cater for both the military and civil markets. Its development was...

conference paper 1996

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Airborne SAR sensor development and validation

Snoeij, P. (author), Pouwels, H. (author), Koomen, P.J. (author), Hoogeboom, P. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The PHARUS system is an example of a high resolution aircraft SAR sensor. Specially the PHARUS system, due to the flexibility of the operating modes, is a candidate to be used complementary with present and planned spacebome systems. The system can also be used as a demonstration system for future spacebome systems such as ESA's AS AR. This...

conference paper 1996

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Amplitude and Phase Calibration of an Dual Polarized Active Phased Array Antenna

Vermeulen, B.C.B. (author), Paquay, M.H.A. (author), Koomen, P.J. (author), Hoogeboom, P. (author), Snoeij, P. (author), Pouwels, H. (author), TNO Fysisch en Elektronisch Laboratorium (author)

In the Netherlands, a Polarimetrie C-band aircraft SAR (Synthetic Aperture Radar) has been developed. The project is called PHARUS, an acronym for Phased Array Universal SAR. This instrument serves remote sensing applications. The antenna system contains 48 modules (expandable to 96). A module is composed of a Transmit/Receive (T/R) module, a...

conference paper 1996

document

The Design and Development of a Polarimetric Phased Array Airborne SAR Sensor

Snoeij, P. (author), Pouwels, H. (author), Koomen, P.J. (author), Vermeulen, B.C.B. (author), Hoogeboom, P. (author), TNO Fysisch en Elektronisch Laboratorium (author)

A polarimetric C-band airborne SAR has been developed in the Netherlands. The system makes use of a phased array antenna with solid state amplifiers. The project consists of two phases, a definition phase and a realization phase. The definition phase consisted of the actual realization of a SAR research system, which made its first successful...

conference paper 1996

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PHARUS: PHased ARray Universal SAR

TNO Fysisch en Elektronisch Laboratorium (author), Paquay, M.H.A. (author), Vermeulen, B.C.B. (author), Koomen, P.J. (author), Hoogeboom, P. (author), Snoeij, P. (author), Pouwels, H. (author)

In the Netherlands, a polarimetric C-band aircraft SAR (Synthetic Aperture Radar) has been developed. The project is called PHARUS, an acronm for PHased ARray Universal SAR. This instrument serves remote sensing applications. The antenna system contains 48 active modules (expandable to 96). A module is composed of a Transmit/Receive section, a...

conference paper 1996

document

Internal and External Calibration of the PHARUS Polarimetric Airborne SAR (abstract)

TNO Fysisch en Elektronisch Laboratorium (author), Snoeij, P. (author), Pouwels, H. (author), Paquay, M.H.A. (author), Koomen, P.J. (author), Hoogeboom, P. (author)

conference paper 1996

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Airborne Microwave Remote Sensor Capabilities in the Netherlands

Snoeij, P. (author), Pouwels, H. (author), Hoogeboom, P. (author), Hoeke, B. (author)

Groundbased scatterometry in The Netherlands has proven to be essential in studying the scattering of microwaves by vegetation and sea. The results of groundbased measurements were among others used for the development of suitable models and for the design of a digital and calibrated airborne X-band SLAR system. Among others the multitemporal...

conference paper 1996

document

Design and Calibration of the PHARUS Polarimetric Airborne SAR

Snoeij, P. (author), Hoogeboom, P. (author), Koomen, P.J. (author), Vermeulen, B.C.B. (author), Pouwels, H. (author)

The PHARUS system uses a phased array antenna with solid state amplifiers. The project consisted of two phases, a definition phase and a realization phase. The definition phase consisted of the actual realization of a SAR research system called PHARS, which made its first successful testflight in November 1990. The research system is based on...

conference paper 1996

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VIERS-1 Final report phase 4

TNO Fysisch en Elektronisch Laboratorium (author), Janssen, P.A.E.M. (author), Calkoen, C.J. (author), van Halsema, D. (author), Oost, W.A. (author), Snoeij, P. (author), Wallbrink, H. (author)

report 1995

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VIERS-1 Final report phase 4A

TNO Fysisch en Elektronisch Laboratorium (author), Janssen, P.A.E.M. (author), Wallbrink, H. (author), Calkoen, C.J. (author), van Halsema, D. (author), Janssen, H. (author), Oost, W.A. (author), Snoeij, P. (author)

report 1994

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Calibration aspects of a polarimetric phased array airborne SAR [L'Etalonnage d'un SAR aeroporte polarimetrique a antenna active}

Snoeij, P. (author), Hoogeboom, P. (author), Koomen, P.J. (author), Vermeulen, B.C.B. (author), Paquay, M.H.A. (author), Pouwels, H. (author)

Purpose of calibration is to get an accurate and Precise instrument. The precision of the instrument can be determined using internal calibration, while the accuracy is denoted with absolute calibration. With internal calibration only the instrument is considered. Because of practical considerations the antenna is usually discarded in this type...

conference paper 1994

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VIERS-1 Final report phase 3

Fysisch en Elektronisch Laboratorium TNO (author), Snoeij, P. (author), van Halsema, D. (author), Vogelzang, J. (author), Waas, S. (author), Zecchetto, S. (author), Janssen, H. (author), Oost, W.A. (author), Jaehne, B. (author), Calkoen, C.J. (author)

report 1993

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PHARUS: Airborne SAR Development in the Netherlands

Hoogeboom, P. (author), Koomen, P.J. (author), Snoeij, P. (author), Pouwels, H. (author)

The PHARUS project (PHARUS stands for Phased Array Universal SAR) aims for a polarimetric C-band aircraft SAR that will be finalized in 1994. The system will make use of a phased array antenna with solid state amplifiers. The project consists of two phases, a definition phase and a realization phase. The definition phase was intended to increase...

conference paper 1992

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The PHARUS Project; Real Time Digital Processing of Airborne Polarimetric Radar Signals

Pouwels, H. (author), Hoogeboom, P. (author), Koomen, P.J. (author), Snoeij, P. (author)

The Dutch PHARUS project aims for the developrlenÈ of a polarimetric C-band aircraft SAR, to be finalized in 1994. The PHARUS systen consists of three subsystens: the radar, the subsystem for the onboard data processing and recording and the ground-based subsystem for SAR processing. PHARUS is a very flexible system with numerous operating modes...

conference paper 1992

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Error Bounds in the Phased Array Antenna. A statistical Model

Vellekoop, A.R. (author), Snoeij, P. (author), Koomen, P.J. (author), Fysisch en Elektronisch Laboratorium TNO (author)

Expressions are generated for the probabilistic analysis of phased-array antenna-pattern degradation subject to random errors in the excitation coefficients and angle measurement errors by means of a model based upon a statistical coefficient of variation model. The expressions are exercised and compared to the exact solution using an example of...

conference paper 1991

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Comparison of Microwave Backscatter Measurements and Small-scale Surface Wave Measurements Made from the Dutch Ocean Research Tower "Noordwijk"

Snoeij, P. (author), van Halsema, D. (author), Oost, W.A. (author), Calkoen, C.J. (author), Vogelzang, J. (author), Waas, S. (author), Jaehne, B. (author), Fysisch en Elektronisch Laboratorium TNO (author)

To improve the understanding of the interaction between microwaves and water waves the VIERS-l project started in 1986 with the preparation of two wind/wave tank experiments and an ocean tower experiment. In February 1988, combined measurements of microwave backscatter, wind, waves and gas exchange have been carried out in the large Delft...

conference paper 1991