Design and optimization of a Ku-band rotating, range-gated fanbeam scatterometer

Lin, Wenming; Dong, Xiaolong

doi:10.1080/01431161003674626

Cited by 35 publications

(22 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, it is not necessary to consider its beam balance for RFSCAT, which is an important issue for multiple fixed fanbeam scatterometers [3], [4]. Compared with rotating pencilbeam scatterometer, RFSCAT can also give more diverse observing views, since the spinning rate of RFSCAT antenna is much lower than rotating pencil-beam type, which also shows a potential improvement for the retrieval performance of wind direction [2], [5].…”

Section: Introductionmentioning

confidence: 94%

“…Rotating fan-beam scatterometer (RFSCAT) is a new type that has more flexible views and larger observing swaths than fixed fan-beam ones, thus have more advantages in removing ambiguous solutions for wind retrieving [1], [2]. Moreover, it is not necessary to consider its beam balance for RFSCAT, which is an important issue for multiple fixed fanbeam scatterometers [3], [4].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Calibration and Estimation of Attitude Errors for a Rotating Fan-Beam Scatterometer Using Calibration Ground Stations

Zhu

Dong

Lin

et al. 2015

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

Self Cite

View full text Add to dashboard Cite

The rotating fan-beam scatterometer (RFSCAT) onboard Chinese-French Oceanic SATellite (CFOSAT) due to launch in 2018 is a new type of radar scatterometer system for ocean surface wind vector measurement. It can give observations with more azimuth and incidence angles for a single wind vector cell (WVC) than other available scatterometers. This has been proved effective in bettering the retrieved wind quality by the simulation approach. However, its innovative observing geometry is challenging for the coming in-orbit external calibration. In this paper, CFOSAT attitude errors are estimated, and its antenna gain pattern is monitored and verified based on the external calibration strategy of a Ku-band scatterometer employing calibration ground stations (CGSs). The effects of satellite attitude errors on the measurements are also analyzed, together with simulation results for the external calibration. It is shown that a gain pattern with accuracy of 0.08 dB and attitude errors within 0.025 are achieved.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Calibration and Estimation of Attitude Errors for a Rotating Fan-Beam Scatterometer Using Calibration Ground Stations

Zhu

Dong

Lin

et al. 2015

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is an inherent factor of scatterometer measurements for a given set of observing geometry and scatterometer parameters. A comprehensive study of the relationship between the RFSCAT instrument parameters and the K pc value has been performed in [11] and [13], where K pc is simply estimated by the normalized standard deviation of the backscattered signal power for a certain slice. Since the Doppler frequency changes as the antenna rotates, the number of FFT bins and the slice band used to calculate K pc vary with the observing azimuth angles, and in turn, result in an azimuthal-dependent communication error.…”

Section: B Error Sources Of σ 0 Measurementsmentioning

confidence: 99%

“…Comparing to the multiple fixed fan-beam scatterometers and the rotating pencil-beam scatterometers, RFSCAT has a more flexible observing geometry, i.e., the number of acquisitions and the observing azimuth angles vary with the cross-track location of the wind vector cell (WVC). This shows potential abilities in improving the accuracy of retrieved wind vectors [10], [11]. Furthermore, the multiple observations with different incidence angles over a certain WVC open a way to study the rain impact on the backscatter of radar scatterometer.…”

mentioning

confidence: 92%

A Preliminary Study of the Calibration for the Rotating Fan-Beam Scatterometer on CFOSAT

Zhu

Dong

Lin

et al. 2015

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

Self Cite

View full text Add to dashboard Cite

The first rotating fan-beam scatterometer (RFSCAT) will be launched onboard the Chinese-French Oceanic Satellite (CFOSAT) in 2018. It provides a set of radar cross-section (σ 0 ) measurements at different azimuth/incidence angles over a wind vector cell (WVC), in order to determine the near-surface wind field using the backscatter model, i.e., the so-called geophysical model function (GMF). The accuracy of the retrieved wind vector is a sensitive function of the radiometric accuracy of the σ 0 measurements. Therefore, in-flight calibration, including the loop-back (internal) calibration and the external calibration performed with natural extended-area targets, is studied in this paper. Several homogeneous areas over land are first analyzed to check the stability and azimuthal dependence of the σ 0 over these areas. A new calibration mask of the homogeneous land areas is generated and will be used by RFSCAT calibration. Then a simple method of external calibration is proposed to eliminate the azimuthal-dependent σ 0 errors induced by the insertion loss of the rotating joint, which can be applied to both the rotating pencil-beam scatterometers and the coming RFSCAT. The "observed" σ 0 of RFSCAT is simulated using the Seasat-A scatterometer (SASS) measurements and the "perturbed" azimuthal-dependent σ 0 errors. The latter is then tracked by the proposed external calibration. The results show that the accuracy of gain corrections is up to 0.2 dB, ensuring consistency between different azimuthal measurements.Index Terms-External calibration, homogeneous areas, inflight calibration, internal calibration, rotating fan-beam scatterometer (RFSCAT).

show abstract

“…-SCAT a wind scatterometer SCAT to measure the wind vector, radar in Ku-Band aiming at moderate incidence angles (26° to 46°) with a rotating fan-beam antenna (see [1])…”

Section: Introductionmentioning

confidence: 99%

CFOSAT: a new Chinese-French satellite for joint observations of ocean wind vector and directional spectra of ocean waves

et al. 2016

View full text Add to dashboard Cite

CFOSAT (the China France Oceanography Satellite) is a joint mission from the Chinese and French Space Agencies, devoted to the observation ocean surface wind and waves so as to improve wind and wave forecast for marine meteorology, ocean dynamics modeling and prediction, climate variability knowledge, fundamental knowledge of surface processes. Currently under Phase D (manufacturing phase), the launch is now planned for mid-2018 the later. The CFOSAT will carry two payloads, both Ku-Band radar: the wave scatterometer (SWIM) and the wind scatterometer (SCAT). Both instruments are based on new concepts with respect to existing satellite-borne wind and wave sensors. Indeed, one of the originalities of CFOSAT is that it will provide simultaneously and in the same zone, the directional spectra of ocean waves and the wind vector. The concept used to measure the directional spectra of ocean waves has never been used from space until now: it is based on a near-nadir incidence pointing, rotating fan-beam radar, used in a real-aperture mode. In this paper we present the CFOSAT mission, its objectives and main characteristics. We then focus on the SWIM instrument, the expected geophysical products and performances. Finally, we present ongoing studies based on existing satellite data of directional spectra of ocean waves (Sentinel-1,..) and carried out in preparation to CAL/VAL activities and to future data exploitation.

show abstract

Design and optimization of a Ku-band rotating, range-gated fanbeam scatterometer

Cited by 35 publications

References 11 publications

Calibration and Estimation of Attitude Errors for a Rotating Fan-Beam Scatterometer Using Calibration Ground Stations

Calibration and Estimation of Attitude Errors for a Rotating Fan-Beam Scatterometer Using Calibration Ground Stations

A Preliminary Study of the Calibration for the Rotating Fan-Beam Scatterometer on CFOSAT

CFOSAT: a new Chinese-French satellite for joint observations of ocean wind vector and directional spectra of ocean waves

Contact Info

Product

Resources

About