Posicionamento por ponto preciso estático e cinemático: implementação e análise
Carregando...
Data
2006-10-31
Autores
Faustino, Renata Cristina [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nesta dissertação investiga-se o Posicionamento por Ponto Preciso (PPP), nos modos estático e cinemático, utilizando o Filtro de Kalman Estendido. Foram corrigidos os erros devido aos efeitos da refração troposférica, relatividade, movimento de rotação da Terra, variações das marés terrestres, correção do centro de fase da antena do satélite e fase Wind- up. Os efeitos devido à ionosfera foram minimizados através da combinação linear Ion-Free. A perda de ciclo foi detectada através da combinação linear widelane, envolvendo as duas observáveis: fase da onda portadora e pseudodistância. Quando a perda de ciclo é detectada, uma nova ambigüidade é inicializada no lugar da antiga. As implementações foram realizadas no software FILTER_FCT, em desenvolvimento na FCT/UNESP, o qual processava apenas a pseudodistância. Visando mostrar a acurácia que pode ser obtida com o PPP, foram realizados três experimentos: PPP no modo estático, PPP estático simulando o modo cinemático e PPP cinemático. No primeiro e no segundo experimentos foram utilizados dados das estações GPS: PPTE, VICO, RIOD e FORT, pertencentes à Rede Brasileira de Monitoramento Contínuo (RBMC), e da estação FRDN, localizada em Fredericton, no Canadá. No terceiro experimento foram utilizados dados do receptor GPS a bordo do satélite CHAMP. No PPP estático, utilizou-se como estratégia de processamento a modificação da variância das coordenadas e do relógio do receptor na matriz de variância-covariância do Filtro de Kalman Estendido. Verificou-se uma discrepância em relação às coordenadas consideradas verdadeiras na ordem de decímetros, com exceção das estações VICO e RIOD, que foram da ordem de centímetros.
In this dissertation the Precise Point Positioning (PPP), in static and kinematic modes, using Extended Kalman Filter is investigated. The errors due to troposphere refraction, relativity, movement of Earth's rotation, tide loading, satellite antenna phase center offset and phase wind-up were corrected. The effects due to ionosphere were minimized through the Ionospheric-Free linear combination. The widelane combination, involving phase and pseduorange, was used to detect cycle slips. When a cycle slip is detected, a new ambiguity is initialized in the place of the old one. The implementations were accomplished in the FILTER_FCT software. To show the accuracy in the PPP, three experiments were accomplished: PPP in the static mode, PPP in the static mode simulating the kinematic mode and PPP in kinematic mode. In the first and second experiments, data from PPTE, VICO, RIOD and FORT stations belonging to Brazilian Network for Continuous Monitoring (RBMC), and FRDN station located in Fredericton, Canada, were used. In the third experiment data from a GPS receiver on board of the CHAMP satellite were used. In static PPP, the modification of the coordinates variance and the receiver clock was used as processing strategy. The discrepanc ies obtained in the static positioning were on the order of decimeters, except for VICO and RIOD stations where they were on the order of centimeters. When the clock receiver variance was increased from (3.300)ø mø to (10.000)ø mø , the values of the discrepancies also increased, on the order of centimeters. Then, there is influence of the receiver clock variance in the estimated coordinates. The residual part of the tropospheric effects was estimated with the introduction of a scale factor in the processing.
In this dissertation the Precise Point Positioning (PPP), in static and kinematic modes, using Extended Kalman Filter is investigated. The errors due to troposphere refraction, relativity, movement of Earth's rotation, tide loading, satellite antenna phase center offset and phase wind-up were corrected. The effects due to ionosphere were minimized through the Ionospheric-Free linear combination. The widelane combination, involving phase and pseduorange, was used to detect cycle slips. When a cycle slip is detected, a new ambiguity is initialized in the place of the old one. The implementations were accomplished in the FILTER_FCT software. To show the accuracy in the PPP, three experiments were accomplished: PPP in the static mode, PPP in the static mode simulating the kinematic mode and PPP in kinematic mode. In the first and second experiments, data from PPTE, VICO, RIOD and FORT stations belonging to Brazilian Network for Continuous Monitoring (RBMC), and FRDN station located in Fredericton, Canada, were used. In the third experiment data from a GPS receiver on board of the CHAMP satellite were used. In static PPP, the modification of the coordinates variance and the receiver clock was used as processing strategy. The discrepanc ies obtained in the static positioning were on the order of decimeters, except for VICO and RIOD stations where they were on the order of centimeters. When the clock receiver variance was increased from (3.300)ø mø to (10.000)ø mø , the values of the discrepancies also increased, on the order of centimeters. Then, there is influence of the receiver clock variance in the estimated coordinates. The residual part of the tropospheric effects was estimated with the introduction of a scale factor in the processing.
Descrição
Palavras-chave
Cartografia, GPS (Programa de computador), Kalman, Filtragem de, Precise Point Positioning (PPP), GPS observable errors, Extended Kalman filter, Static and kinematic PPP, CHAMP Satellite
Como citar
FAUSTINO, Renata Cristina. Posicionamento por ponto preciso estático e cinemático: implementação e análise. 2006. 105 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências e Tecnologia, 2006.