Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry
Today, land and ocean observations are crucial for monitoring climate change. The method of GNSS reflectometry is an opportunistic way to provide low-cost observations of many geophysical parameters. However, although this method has been the subject of numerous research studies, work is still in pr...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-08-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/15/17/4192 |
| _version_ | 1827727884707430400 |
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| author | Nolan Varais Jérôme Verdun José Cali Laurent Lestarquit |
| author_facet | Nolan Varais Jérôme Verdun José Cali Laurent Lestarquit |
| author_sort | Nolan Varais |
| collection | DOAJ |
| description | Today, land and ocean observations are crucial for monitoring climate change. The method of GNSS reflectometry is an opportunistic way to provide low-cost observations of many geophysical parameters. However, although this method has been the subject of numerous research studies, work is still in progress to improve its possibilities and fields of application. This paper focuses on GNSS reflectometry using carrier phase measurements for water altimetry measurements. The difficulties in implementing such a method lie in the need to collect a coherent signal and to solve the integer ambiguity value. In this context, the implementation of innovative signal processing is described, including the correlation of the reflected signals in dedicated software and the prolongation of the coherent integration time to enhance signal coherency. These processes were applied to data collected over Carcans-Hourtin Lake in France to compute the height of the reflection surface which was then compared to in situ GNSS buoy height measurements. The results show that at 300 ft (91.44 m), the differences between the lake heights measured with the buoy and with the reflectometry data can reach less than 1 cm for the L1, E1 and E5 GNSS signals. In addition, the slope of the geoid estimated with the reflectometry data is very consistent with that of the RAF20 geoid model, with a difference of up to less than 2 mm/km. |
| first_indexed | 2024-03-10T23:14:16Z |
| format | Article |
| id | doaj.art-516f6e9d3b084ac49bd79aec7ddd891c |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T23:14:16Z |
| publishDate | 2023-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-516f6e9d3b084ac49bd79aec7ddd891c2023-11-19T08:45:43ZengMDPI AGRemote Sensing2072-42922023-08-011517419210.3390/rs15174192Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS ReflectometryNolan Varais0Jérôme Verdun1José Cali2Laurent Lestarquit3Laboratoire Géomatique et Foncier (UR 4630), Conservatoire National des Arts et Métiers (Cnam), Hesam Université, 72000 Le Mans, FranceLaboratoire Géomatique et Foncier (UR 4630), Conservatoire National des Arts et Métiers (Cnam), Hesam Université, 72000 Le Mans, FranceLaboratoire Géomatique et Foncier (UR 4630), Conservatoire National des Arts et Métiers (Cnam), Hesam Université, 72000 Le Mans, FranceCentre National d’Etudes Spatiales, 31400 Toulouse, FranceToday, land and ocean observations are crucial for monitoring climate change. The method of GNSS reflectometry is an opportunistic way to provide low-cost observations of many geophysical parameters. However, although this method has been the subject of numerous research studies, work is still in progress to improve its possibilities and fields of application. This paper focuses on GNSS reflectometry using carrier phase measurements for water altimetry measurements. The difficulties in implementing such a method lie in the need to collect a coherent signal and to solve the integer ambiguity value. In this context, the implementation of innovative signal processing is described, including the correlation of the reflected signals in dedicated software and the prolongation of the coherent integration time to enhance signal coherency. These processes were applied to data collected over Carcans-Hourtin Lake in France to compute the height of the reflection surface which was then compared to in situ GNSS buoy height measurements. The results show that at 300 ft (91.44 m), the differences between the lake heights measured with the buoy and with the reflectometry data can reach less than 1 cm for the L1, E1 and E5 GNSS signals. In addition, the slope of the geoid estimated with the reflectometry data is very consistent with that of the RAF20 geoid model, with a difference of up to less than 2 mm/km.https://www.mdpi.com/2072-4292/15/17/4192GNSSreflectometrycarrier phasealtimetrysignal processingsoftware |
| spellingShingle | Nolan Varais Jérôme Verdun José Cali Laurent Lestarquit Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry Remote Sensing GNSS reflectometry carrier phase altimetry signal processing software |
| title | Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry |
| title_full | Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry |
| title_fullStr | Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry |
| title_full_unstemmed | Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry |
| title_short | Lake Altimetry Using Long Coherent Integration Carrier Phase Measurements from Airborne GNSS Reflectometry |
| title_sort | lake altimetry using long coherent integration carrier phase measurements from airborne gnss reflectometry |
| topic | GNSS reflectometry carrier phase altimetry signal processing software |
| url | https://www.mdpi.com/2072-4292/15/17/4192 |
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