Improved GNSS-R altimetry methods: experimental demonstration using dual frequency data
Altimetric performance of Global Navigation Satellite System - Reflectometry (GNSS-R) instruments is highly dependent on receiver's bandwidth. The altimetric delay is usually computed from the time difference between the peak of the direct signal waveform, and the maximum of the derivative of t...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/360011 |
| Acceso en línea: | https://hdl.handle.net/2117/360011 |
| Access Level: | acceso abierto |
| Palabra clave: | Global Positioning System Artificial satellites in remote sensing GNSS-R ocean altimetry sea surface height airborne waveform bandwidth coherent integration time Microwave Interferometric Reflectometer (MIR) Sistema de posicionament global Satèl·lits artificials en teledetecció |
| Sumario: | Altimetric performance of Global Navigation Satellite System - Reflectometry (GNSS-R) instruments is highly dependent on receiver's bandwidth. The altimetric delay is usually computed from the time difference between the peak of the direct signal waveform, and the maximum of the derivative of the reflected signal waveform. Dual frequency data gathered by the MIR (Microwave Interferometric Reflectometer) in the Bass Strait suggests that this approach is only valid for flat surfaces, and large bandwidth receivers. This work presents and analyses improved methods to compute the altimetric observables using GNSS-R. They show improved performance when using real data. These novel methods are the Peak-to-Minimum of the 3rd Derivative for narrow-band codes (e.g. L1 C/A), and the Peak-to-Half Power (mid-rise leading-edge) for large bandwidth codes (e.g. L5 or E5a codes). The key difference between these methods is the determination of the delay position in the reflected signal waveform in order to compute the altimetric observable. Airborne experimental results comparing the different methods, bands and GNSS-R processing techniques show that centimeter level accuracy can be achieved. |
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