First spaceborne phase altimetry over sea ice using TechDemoSat‐1 GNSS‐R signals

Li, Weiqiang; Cardellach, Estel; Fabra, Fran; Rius, A.; Ribó, S.; Martín-Neira, Manuel

doi:10.1002/2017gl074513

Cited by 165 publications

(145 citation statements)

References 38 publications

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“…3) The presence of ice over the lake surface can affect the water level estimation. The GNSS signal can penetrate the ice and snow layers, and the reflected signal from the bottom ice/water interface dominates the overall return echo (W. Li et al, 2017;Mayers & Ruf, 2018). This could be the reason for the lower water levels measured in T1-T4.…”

Section: Lake Level From Group Delay Measurementsmentioning

confidence: 99%

“…From the coherent GNSS reflections, it is possible to perform more precise altimetry by exploiting the carrier phase information. GNSS‐R phase altimetry has been verified in different applications, such as ocean tides and sea ice observations from high‐altitude ground‐based experiments (e.g., Fabra et al, ; Semmling et al, ), water surface topography measurement from airborne platforms (e.g., Semmling et al, , ), and ice altimetry from spaceborne (Cardellach et al, ; W. Li et al, ). Smooth lake surface can improve the coherence of L‐band signal and offers the possibility of phase delay altimetry.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lake Level and Surface Topography Measured With Spaceborne GNSS‐Reflectometry From CYGNSS Mission: Example for the Lake Qinghai

Cardellach

Fabra

et al. 2018

Geophysical Research Letters

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This paper demonstrates inland water altimetry of spaceborne Global Navigation Satellite System‐Reflectometry (GNSS‐R) using the Cyclone GNSS (CYGNSS) mission data. From 12 tracks of raw data overpassing the Lake Qinghai, the bistatic group delay and carrier phase delay are extracted from the quasi‐specular GNSS reflections. The water levels derived from the group delay observations are consistent with the Cryosat‐2 and in situ gauge measurements. The surface topography profiles from the phase delay measurements show good self‐consistence along the coincident tracks. Decimeter‐level surface height anomalies are resolved with the phase delay measurements, which can be associated with the accuracy degradation of the geoid model in this region. Systematic errors remain in both group delay and phase delay altimetry measurements, which are attributed to the receiver orbit errors and ionospheric correction residuals. These limitations can be eliminated in further GNSS‐R missions dedicated to altimetry applications.

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Section: Lake Level From Group Delay Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lake Level and Surface Topography Measured With Spaceborne GNSS‐Reflectometry From CYGNSS Mission: Example for the Lake Qinghai

Cardellach

Fabra

et al. 2018

Geophysical Research Letters

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“…However, other Earth observation applications, such as ice sheet and ocean altimetry (e.g., Cardellach et al, 2004;Cartwright et al, 2018;, the monitoring of soil moisture (Chew et al, 2016), and the cryosphere (e.g., Belmonte Rivas et al, 2010;Gleason, 2006), are also being investigated. Cryospheric applications include the detection and altimetry of sea ice (e.g., Alonso-Arroyo et al, 2017;Hu et al, 2017;Li et al, 2017;Yan & Huang, 2016), the altimetry of glacial ice (e.g., Cardellach et al, 2004;Cartwright et al, 2018;Rius et al, 2017), and permittivity of reflective surfaces (Belmonte Rivas et al, 2010;Fabra et al, 2012). The use of these signals of opportunity and the need only for a receiver in space mean that GNSS-R is an extremely low-cost and, being a passive system, low-power method of remote sensing.…”

Section: Introductionmentioning

confidence: 99%

Sea Ice Detection Using GNSS‐R Data From TechDemoSat‐1

2019

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A new method for the detection of sea ice using GNSS‐R (Global Navigation Satellite Systems Reflectometry) is presented and applied to 33 months of data from the U.K. TechDemoSat‐1 mission. This method of sea ice detection shows the potential for a future GNSS‐R polar mission, attaining an agreement of over 98% and 96% in the Antarctic and Arctic, respectively, when compared to the European Space Agency's Climate Change Initiative sea ice concentration product. The algorithm uses a combination of two parameters derived from the delay‐Doppler Maps to quantify the spread of power in delay and Doppler. Application of thresholds then allows sea ice to be distinguished from open water. Differences between the TechDemoSat‐1 sea ice detection and comparison data sets are explored. The results provide information on the seasonal and multiyear changes in sea ice distribution of the Arctic and Antarctic. Future potential and applications of this technique are discussed.

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“…This instrument on TDS-1 could receive GPS L1 and L2C signals and gathered many useful and important spaceborne GNSS-R data for scientific research [32]. Much of the data from TechDemoSat-1 GNSS-R experiment has been made available at the MERRByS website and analyzed to perform geophysical parameter retrievals [14,15,18].…”

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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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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First spaceborne phase altimetry over sea ice using TechDemoSat‐1 GNSS‐R signals

Cited by 165 publications

References 38 publications

Lake Level and Surface Topography Measured With Spaceborne GNSS‐Reflectometry From CYGNSS Mission: Example for the Lake Qinghai

Lake Level and Surface Topography Measured With Spaceborne GNSS‐Reflectometry From CYGNSS Mission: Example for the Lake Qinghai

Sea Ice Detection Using GNSS‐R Data From TechDemoSat‐1

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

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