Circular Regression Applied to GNSS-R Phase Altimetry

Kucwaj, Jean-Christophe; Reboul, Serge; Stienne, Georges; Choquel, Jean-Bernard; Benjelloun, M.

doi:10.3390/rs9070651

Cited by 16 publications

(6 citation statements)

References 35 publications

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“…Perfectly flat surfaces such as water or ice can be considered for altimetry measurement (Fabra et al, 2011;Hajj & Zuffada, 2003). The circular regression technique referred to as carrier phase altimetry is more precise than the group delay altimetry (code delay) technique (Kucwaj et al, 2017). Radar altimetry considered as the primary spaceborne sea surface observation technology, is constrained by the mode of sub-satellite observation, suitable only for features on scales larger than 400 km (Fu et al, 2010).…”

Section: Ocean Altimetrymentioning

confidence: 99%

Remote sensing and its applications using GNSS reflected signals: advances and prospects

Jin,

Camps,

Jia

et al. 2024

Satell Navig

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The Global Navigation Satellite Systems (GNSS), including the US’s GPS, China’s BDS, the European Union’s Galileo, and Russia’s GLONASS, offer real-time, all-weather, any-time, anywhere and high precision observations by transmitting L band signals continuously, which have been widely used for positioning, navigation and timing. With the development of GNSS technology, it has been found that GNSS-reflected signals can be used to detect Earth’s surface characteristics together with other signals of opportunity. In this paper, the current status and latest advances are presented on Global Navigation Satellite System-Reflectometry (GNSS-R) in theory, methods, techniques and observations. New developments and progresses in GNSS-R instruments, theoretical modeling, and signal processing, ground and space-/air-borne experiments, parameters retrieval (e.g. wind speed, sea surface height, soil moisture, ice thickness), sea surface altimetry and applications in the atmosphere, oceans, land, vegetation, and cryosphere are given and reviewed in details. Meanwhile, the challenges in the GNSS-R development of each field are also given. Finally, the future applications and prospects of GNSS-R are discussed, including multi-GNSS reflectometry, new GNSS-R receivers, GNSS-R missions, and emerging applications, such as mesoscale ocean eddies, ocean phytoplankton blooms, microplastics detection, target recognition, river flow, desert studies, natural hazards and landslides monitoring.

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Section: Ocean Altimetrymentioning

confidence: 99%

Remote sensing and its applications using GNSS reflected signals: advances and prospects

Jin,

Camps,

Jia

et al. 2024

Satell Navig

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“…The software receiver is constructed according to [27] to derive the in-phase and quadrature components of the reflected signal , I R 0 and Q R 0 , after the tracking stage (Equations ( 1)-( 8) may be found in [27] with changes in notation). The direct and reflected signal, S D and S R , respectively, are defined by:…”

Section: Tracking and Retrackingmentioning

confidence: 99%

“…Multiple flights were conducted along Opal Coast between the cities of Calais and Boulogne-sur-Mer, France, in the North Sea. A software receiver based on [27] processes the direct and reflected signals. The reflected signals are retracked, aided by the signal path difference between the direct and reflected links retrieved from a specular reflection geometrical model [28].…”

Section: Introductionmentioning

confidence: 99%

Airborne Coherent GNSS Reflectometry and Zenith Total Delay Estimation over Coastal Waters

et al. 2022

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High-precision GNSS (global navigation satellite e system) measurements can be used for remote sensing and nowadays play a significant role in atmospheric sounding (station data, radio occultation observations) and sea surface altimetry based on reflectometry. A limiting factor of high-precision reflectometry is the loss of coherent phase information due to sea-state-induced surface roughness. This work studies airborne reflectometry observations recorded over coastal waters to examine the sea-state influence on Doppler distribution and the coherent residual phase retrieval. From coherent observations, the possibility of zenith total delay inversion is also investigated, considering the hydrostatic mapping factor from the Vienna mapping function and an exponential vertical decay factor depending on height receiver changes. The experiment consists of multiple flights performed along the coast between the cities of Calais and Boulogne-sur-Mer, France, in July 2019. Reflected signals acquired in a right-handed circular polarization are processed through a model-aided software receiver and passed through a retracking module to obtain the Doppler and phase-corrected signal. Results from grazing angle observations (elevation < 15°) show a high sensitivity of Doppler spread with respect to sea state with correlations of 0.75 and 0.88 with significant wave height and wind speed, respectively. An empirical Doppler spread threshold of 0.5 Hz is established for coherent reflections supported by the residual phase observations obtained. Phase coherence occurs in 15% of the observations; however, the estimated zenith total delay for the best event corresponds to 2.44 m, which differs from the typical zenith total delay (2.3 m) of 5%.

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“…However, this is a complex problem. Scholars have proposed methods to avoid calculating the integer ambiguity [27][28][29], and these methods can achieve a temporal resolution of up to 1 min. Nonetheless, during emergency situations such as flash floods, water authorities require even higher temporal resolution of water level data to effectively develop emergency response measures.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Water Level Monitoring Based on GNSS Dual-Antenna Attitude Measurement

Pengjie

Pang

et al. 2023

Remote Sensing

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Real-time and high-precision water level monitoring is crucial for the fields of hydrology, hydraulic engineering, and disaster prevention and control. The most prevalent method for measuring water level is through the use of water level gauges, which can be costly and have limited coverage. In recent years, Global Navigation Satellite System Reflectometry (GNSS-R) technology has emerged as a promising approach for water level monitoring due to its low cost and high coverage. However, a limitation of current GNSS-R technology is the extended time required to record signals, which hinders its potential for real-time application. This paper introduces a novel real-time water level monitoring method based on GNSS dual-antenna attitude measurement and develops a model to invert water level based on baseline vector. This method uses double-difference observations to eliminate errors caused by various factors, such as satellite and receiver clock, and ionospheric and tropospheric delay. To avoid the impact of detecting and correcting cycle slips during real-time operations, a single-epoch calculation method is introduced. In order to verify the stability and reliability of our method, field tests were carried out at Dongshahe Station in Beijing. We obtained water level data with a time resolution of 1 Hz through field experiments. Experimental data collected from 12 May to 8 June 2022 and from 4 July to 8 August 2022 showed good agreement with on-site water gauge measurements, with root mean square errors of 2.77 cm and 2.54 cm, respectively. Experimental results demonstrate that this method can achieve high-precision, high-temporal-resolution water level monitoring.

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Circular Regression Applied to GNSS-R Phase Altimetry

Cited by 16 publications

References 35 publications

Remote sensing and its applications using GNSS reflected signals: advances and prospects

Remote sensing and its applications using GNSS reflected signals: advances and prospects

Airborne Coherent GNSS Reflectometry and Zenith Total Delay Estimation over Coastal Waters

Real-Time Water Level Monitoring Based on GNSS Dual-Antenna Attitude Measurement

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