First spaceborne observation of sea surface height using GPS‐Reflectometry

Clarizia, Maria Paola; Ruf, Christopher S.; Cipollini, Paolo; Zuffada, Cinzia

doi:10.1002/2015gl066624

Cited by 126 publications

(118 citation statements)

References 19 publications

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“…The equations of computing the latitude and longitude of a specific specular reflected point according to the geometry shown in Figure 4 are provided in this subsection. The locations of specular reflected points can be computed using Equations (5) and (6).…”

Section: Selection Of the Available Reflected Signalsmentioning

confidence: 99%

“…Among the current spaceborne techniques, global navigation satellite system reflectometry (GNSS-R) is an effective and innovative remote sensing technique for the ocean, land and cryosphere [1,2]. It can be used to derive geophysical parameters based on the GNSS L-band signals that are reflected by the Earth's surface under all weather conditions [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spatiotemporal Evaluation of GNSS-R Based on Future Fully Operational Global Multi-GNSS and Eight-LEO Constellations

Gao

Wang

et al. 2018

Remote Sensing

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Spaceborne GNSS-R (global navigation satellite system reflectometry) is an innovative and powerful bistatic radar remote sensing technique that uses specialized GNSS-R instruments on LEO (low Earth orbit) satellites to receive GNSS L-band signals reflected by the Earth's surface. Unlike monostatic radar, the illuminated areas are elliptical regions centered on specular reflection points. Evaluation of the spatiotemporal resolution of the reflections is necessary at the GNSS-R mission design stage for various applications. However, not all specular reflection signals can be received because the size and location of the GNSS-R antenna's available reflecting ground coverage depends on parameters including the on-board receiver antenna gain, the signal frequency and power, the antenna face direction, and the LEO's altitude. Additionally, the number of available reflections is strongly related to the number of GNSS-R LEO and GNSS satellites. By 2020, the Galileo and BeiDou Navigation Satellite System (BDS) constellations are scheduled to be fully operational at global scale and nearly 120 multi-GNSS satellites, including Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) satellites, will be available for use as illuminators. In this paper, to evaluate the future capacity for repetitive GNSS-R observations, we propose a GNSS satellite selection method and simulate the orbit of eight-satellite LEO and partial multi-GNSS constellations. We then analyze the spatiotemporal distribution characteristics of the reflections in two cases: (1) When only GPS satellites are available; (2) when multi-GNSS satellites are available separately. Simulation and analysis results show that the multi-GNSS-R system has major advantages in terms of available satellite numbers and revisit times over the GPS-R system. Additionally, the spatial density of the specular reflections on the Earth's surface is related to the LEO inclination and constellation construction.

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Section: Selection Of the Available Reflected Signalsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Evaluation of GNSS-R Based on Future Fully Operational Global Multi-GNSS and Eight-LEO Constellations

Gao

Wang

et al. 2018

Remote Sensing

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“…This technique, also known as GNSS-Reflectometry (GNSS-R), can provide a dense spatial and temporal sampling capability over the Earth surface in a low-cost way. During the past two decades, several theoretical and experimental studies have been performed to demonstrate the feasibility of ocean altimetry using reflected GNSS signals, e.g., in [2][3][4][5][6][7][8][9], and several studies have been performed on scatterometric applications, such as sea surface wind, sea ice and soil moisture. A comprehensive tutorial of GNSS-R technique and its applications can be found in [10].…”

Section: Introductionmentioning

confidence: 99%

The Impact of Inter-Modulation Components on Interferometric GNSS-Reflectometry

Rius

Fabra

et al. 2016

Remote Sensing

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Abstract:The interferometric Global Navigation Satellite System Reflectometry (iGNSS-R) exploits the full spectrum of the transmitted GNSS signal to improve the ranging performance for sea surface height applications. The Inter-Modulation (IM) component of the GNSS signals is an additional component that keeps the power envelope of the composite signals constant. This extra component has been neglected in previous studies on iGNSS-R, in both modelling and instrumentation. This letter takes the GPS L1 signal as an example to analyse the impact of the IM component on iGNSS-R ocean altimetry, including signal-to-noise ratio, the altimetric sensitivity and the final altimetric precision. Analytical results show that previous estimates of the final altimetric precision were underestimated by a factor of 1.5∼1.7 due to the negligence of the IM component, which should be taken into account in proper design of the future spaceborne iGNSS-R altimetry missions.

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“…So far, one of the main applications of GNSS-R is sea state estimation and monitoring, and several approaches and techniques to estimate the local wind speed from GNSS-R observables have been developed in the last years [16]- [19]. Other very recent applications of the GNSS-R technology concern the surface scattering coefficient retrieval [20], [21], ocean topography [22], oil slick detection [23], [24], and tsunami detection [25], [26]. Due to the absence of a transmitter module, GNSS-R payloads can be mounted on nano-or small-satellites-as the recently launched 3 Cat-2 satellite by UPC [27]-with the potential to be deployed in wide constellations.…”

mentioning

confidence: 99%

Sea Target Detection Using Spaceborne GNSS-R Delay-Doppler Maps: Theory and Experimental Proof of Concept Using TDS-1 Data

Simone

Park

Riccio

et al. 2017

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

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Abstract-This study addresses a novel application of global navigation satellite system-reflectometry (GNSS-R) delay-Doppler maps (DDMs), namely sea target detection. In contrast with other competing remote sensing technologies, such as synthetic aperture radar and optical systems, typically exploited in the field of sea target detection, GNSS-R systems could be employed as satellite constellations, so as to fulfill the temporal requirements for near real-time ships and sea ice sheets monitoring. In this study, the revisit time offered by GNSS-R systems is quantitatively evaluated by means of a simulation analysis, in which three different realistic GNSS-R missions are simulated and analyzed. Then, a sea target detection algorithm from spaceborne GNSS-R DDMs is described and assessed. The algorithm is based on a sea clutter compensation step and uses an adaptive threshold to take into account spatial variations in the sea background and/or noise statistics. Finally, the sea target detector algorithm is tested and validated for the first time ever using experimental GNSS-R data from the U.K. TechDemoSat-1 dataset. Performance is assessed by providing the receiver operating characteristic curves, and some preliminary experimental results are presented.Index Terms-Constant false alarm rate (CFAR), global navigation satellite system-reflectometry (GNSS-R), maritime surveillance, sea state, sea target detection.

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First spaceborne observation of sea surface height using GPS‐Reflectometry

Cited by 126 publications

References 19 publications

Spatiotemporal Evaluation of GNSS-R Based on Future Fully Operational Global Multi-GNSS and Eight-LEO Constellations

Spatiotemporal Evaluation of GNSS-R Based on Future Fully Operational Global Multi-GNSS and Eight-LEO Constellations

The Impact of Inter-Modulation Components on Interferometric GNSS-Reflectometry

Sea Target Detection Using Spaceborne GNSS-R Delay-Doppler Maps: Theory and Experimental Proof of Concept Using TDS-1 Data

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