scholarly journals Above-Ground Biomass Retrieval over Tropical Forests: A Novel GNSS-R Approach with CyGNSS

2020 ◽  
Vol 12 (9) ◽  
pp. 1368 ◽  
Author(s):  
Hugo Carreno-Luengo ◽  
Guido Luzi ◽  
Michele Crosetto
Keyword(s):  
Soil Moisture ◽  
Tropical Forests ◽  
Empirical Relationship ◽  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Above Ground Biomass ◽  
Laser Altimeter ◽  
Ground Biomass ◽  
Global Navigation ◽  
Global Navigation Satellite

An assessment of the National Aeronautics and Space Administration NASA’s Cyclone Global Navigation Satellite System (CyGNSS) mission for biomass studies is presented in this work on rain, coniferous, dry, and moist tropical forests. The main objective is to investigate the capability of Global Navigation Satellite Systems Reflectometry (GNSS-R) for biomass retrieval over dense forest canopies from a space-borne platform. The potential advantage of CyGNSS, as compared to monostatic Synthetic Aperture Radar (SAR) missions, relies on the increasing signal attenuation by the vegetation cover, which gradually reduces the coherent scattering component σ coh , 0 . This term can only be collected in a bistatic radar geometry. This point motivates the study of the relationship between several observables derived from Delay Doppler Maps (DDMs) with Above-Ground Biomass (AGB). This assessment is performed at different elevation angles θ e as a function of Canopy Height (CH). The selected biomass products are obtained from data collected by the Geoscience Laser Altimeter System (GLAS) instrument on-board the Ice, Cloud, and land Elevation Satellite (ICESat-1). An analysis based on the first derivative of the experimentally derived polynomial fitting functions shows that the sensitivity requirements of the Trailing Edge TE and the reflectivity Γ reduce with increasing biomass up to ~ 350 and ~ 250 ton/ha over the Congo and Amazon rainforests, respectively. The empirical relationship between TE and Γ with AGB is further evaluated at optimum angular ranges using Soil Moisture Active Passive (SMAP)-derived Vegetation Optical Depth ( VOD ), and the Polarization Index ( PI ). Additionally, the potential influence of Soil Moisture Content (SMC) is investigated over forests with low AGB.

scholarly journals Modelagem fuzzy aplicada na detecção da vulnerabildade à erosão costeira

2013 ◽  
Vol 19 (4) ◽  
pp. 746-764 ◽  
Author(s):  
Luciana Maria da Silva ◽  
Rodrigo Mikosz Gonçalves ◽  
Milde Maria da Silva Lira ◽  
Pedro de Souza Pereira
Keyword(s):  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite

O crescimento da urbanização vem provocando grandes transformações nas relações sociais e morfológica das áreas costeiras. O presente trabalho tem como objetivo modelar massa de dados de diversas fontes como GNSS (Global Navigation Satellite Systems) e sensoriamento remoto para posteriormente prover a espacialização da vulnerabilidade costeira à erosão utilizando a lógica fuzzy. O método aplicado para análise da vulnerabilidade utilizou variáveis linguísticas, partições fuzzy, intervalos e análises paramétricas que caracterizam a modelagem fuzzy. Após análise, os níveis de vulnerabilidade à erosão costeira ao longo da linha de costa nas cidades do Recife e Jaboatão dos Guararapes no litoral de Pernambuco apresentaram os seguintes resultados: 33,33% da linha de costa possuem vulnerabilidade baixa, 38,15% possui vulnerabilidade moderada, 14,26% vulnerabilidade alta e 14,26% muito alta.

Institutional Aspects of a Global Navigation Satellite System

2000 ◽  
Vol 53 (2) ◽  
pp. 261-271 ◽  
Author(s):  
D. Brocklebank ◽  
J. Spiller ◽  
T. Tapsell
Keyword(s):  
European Space Agency ◽  
Private Investment ◽  
Global Navigation Satellite Systems ◽  
European Symposium ◽  
Economic Regulation ◽  
Navigation Satellite ◽  
The European Union ◽  
Global Navigation ◽  
Global Navigation Satellite ◽  
The Impact

This, and the following three papers, where first presented at GNSS 99, the Second European Symposium on Global Navigation Satellite Systems held in Genoa, Italy from 5th to 8th October 1999.Galileo is being developed as the European contribution to the next generation of navigation satellites to replace GNSS1. Sponsored by the European Union, Galileo will be a civil, internationally controlled and operated system that will secure the long-term availability of satellite-based navigation services for multi-modal purposes throughout the European region and beyond. Galileo will be designed to support a wide variety of applications. These include professional navigation, position reference, safety, emergency, tracking, sport/leisure and governmental. Such services may be open to all, for safety-of-life applications, or for commercial users. In the case of safety and commercial applications in particular, it is imperative that the appropriate institutional control and regulatory framework is in place for purposes of safety and economic regulation. To ensure that the various parties understand their obligations and liabilities, clear legal instruments must be put in place to support the organisational framework. It is planned to attract private investment to fund elements of system development and operation through Private/Public Partnership arrangements. At present there is no institutional, regulatory or legal framework that will enable the early impetus to Galileo development to be maintained. This presents a challenge that Europe must address without delay. It has been the subject of several European Commission studies in the past twelve months. In a complementary activity under contract to the European Space Agency (ESA), a European industry consortium comprising Alcatel, Alenia, DASA and Matra Marconi Space was tasked to complete the preliminary design of the space and ground segments by the Autumn of 1999. One task of this study, led by Matra Marconi Space, relates to a study of the impact of institutional, regulatory and legal issues on the organisation and development of Galileo. This paper describes the studies undertaken into these issues within the overall Galileo development programme.

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