Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications
As opposed to monostatic radars where incoherent backscattering dominates, in bistatic radars, such as Global Navigation Satellite Systems Reflectometry (GNSS-R), the forward scattered signals exhibit both an incoherent and a coherent component. Current models assume that either one or the other are...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-04-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/12/7/1208 |
| _version_ | 1797571159119626240 |
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| author | Joan Francesc Munoz-Martin Raul Onrubia Daniel Pascual Hyuk Park Adriano Camps Christoph Rüdiger Jeffrey Walker Alessandra Monerris |
| author_facet | Joan Francesc Munoz-Martin Raul Onrubia Daniel Pascual Hyuk Park Adriano Camps Christoph Rüdiger Jeffrey Walker Alessandra Monerris |
| author_sort | Joan Francesc Munoz-Martin |
| collection | DOAJ |
| description | As opposed to monostatic radars where incoherent backscattering dominates, in bistatic radars, such as Global Navigation Satellite Systems Reflectometry (GNSS-R), the forward scattered signals exhibit both an incoherent and a coherent component. Current models assume that either one or the other are dominant, and the calibration and geophysical parameter retrieval (e.g., wind speed, soil moisture, etc.) are developed accordingly. Even the presence of the coherent component of a GNSS reflected signal itself has been a matter of discussion in the last years. In this work, a method developed to separate the leakage of the direct signal in the reflected one is applied to a data set of GNSS-R signals collected over the ocean by the Microwave Interferometer Reflectometer (MIR) instrument, an airborne dual-band (L1/E1 and L5/E5a), multi-constellation (GPS and Galileo) GNSS-R instrument with two 19-elements antenna arrays with 4 beam-steered each. The presented results demonstrate the feasibility of the proposed technique to untangle the coherent and incoherent components from the total power waveform in GNSS reflected signals. This technique allows the processing of these components separately, which increases the calibration accuracy (as today both are mixed and processed together), allowing higher resolution applications since the spatial resolution of the coherent component is determined by the size of the first Fresnel zone (300–500 meters from a LEO satellite), and not by the size of the glistening zone (25 km from a LEO satellite). The identification of the coherent component enhances also the location of the specular reflection point by determining the peak maximum from this coherent component rather than the point of maximum derivative of the incoherent one, which is normally noisy and it is blurred by all the glistening zone contributions. |
| first_indexed | 2024-03-10T20:34:57Z |
| format | Article |
| id | doaj.art-e8f88e28cfd4480d808ed0c9a5cbb728 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T20:34:57Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-e8f88e28cfd4480d808ed0c9a5cbb7282023-11-19T21:06:25ZengMDPI AGRemote Sensing2072-42922020-04-01127120810.3390/rs12071208Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel ApplicationsJoan Francesc Munoz-Martin0Raul Onrubia1Daniel Pascual2Hyuk Park3Adriano Camps4Christoph Rüdiger5Jeffrey Walker6Alessandra Monerris7CommSensLab—UPC, Universitat Politècnica de Catalunya—BarcelonaTech, and IEEC/CTE-UPC, 08034 Barcelona, SpainCommSensLab—UPC, Universitat Politècnica de Catalunya—BarcelonaTech, and IEEC/CTE-UPC, 08034 Barcelona, SpainCommSensLab—UPC, Universitat Politècnica de Catalunya—BarcelonaTech, and IEEC/CTE-UPC, 08034 Barcelona, SpainCommSensLab—UPC, Universitat Politècnica de Catalunya—BarcelonaTech, and IEEC/CTE-UPC, 08034 Barcelona, SpainCommSensLab—UPC, Universitat Politècnica de Catalunya—BarcelonaTech, and IEEC/CTE-UPC, 08034 Barcelona, SpainDepartment of Civil Engineering, Monash University, Clayton, VIC 3800, AustraliaDepartment of Civil Engineering, Monash University, Clayton, VIC 3800, AustraliaDepartment of Infrastructure Engineering, The University of Melbourne, Parkville, VIC 3010, AustraliaAs opposed to monostatic radars where incoherent backscattering dominates, in bistatic radars, such as Global Navigation Satellite Systems Reflectometry (GNSS-R), the forward scattered signals exhibit both an incoherent and a coherent component. Current models assume that either one or the other are dominant, and the calibration and geophysical parameter retrieval (e.g., wind speed, soil moisture, etc.) are developed accordingly. Even the presence of the coherent component of a GNSS reflected signal itself has been a matter of discussion in the last years. In this work, a method developed to separate the leakage of the direct signal in the reflected one is applied to a data set of GNSS-R signals collected over the ocean by the Microwave Interferometer Reflectometer (MIR) instrument, an airborne dual-band (L1/E1 and L5/E5a), multi-constellation (GPS and Galileo) GNSS-R instrument with two 19-elements antenna arrays with 4 beam-steered each. The presented results demonstrate the feasibility of the proposed technique to untangle the coherent and incoherent components from the total power waveform in GNSS reflected signals. This technique allows the processing of these components separately, which increases the calibration accuracy (as today both are mixed and processed together), allowing higher resolution applications since the spatial resolution of the coherent component is determined by the size of the first Fresnel zone (300–500 meters from a LEO satellite), and not by the size of the glistening zone (25 km from a LEO satellite). The identification of the coherent component enhances also the location of the specular reflection point by determining the peak maximum from this coherent component rather than the point of maximum derivative of the incoherent one, which is normally noisy and it is blurred by all the glistening zone contributions.https://www.mdpi.com/2072-4292/12/7/1208GNSS-Rseacoherent scatteringincoherent scattering |
| spellingShingle | Joan Francesc Munoz-Martin Raul Onrubia Daniel Pascual Hyuk Park Adriano Camps Christoph Rüdiger Jeffrey Walker Alessandra Monerris Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications Remote Sensing GNSS-R sea coherent scattering incoherent scattering |
| title | Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications |
| title_full | Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications |
| title_fullStr | Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications |
| title_full_unstemmed | Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications |
| title_short | Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications |
| title_sort | untangling the incoherent and coherent scattering components in gnss r and novel applications |
| topic | GNSS-R sea coherent scattering incoherent scattering |
| url | https://www.mdpi.com/2072-4292/12/7/1208 |
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