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Abstract
GNSS systems allow a receiver to the determine its position (including altitude), with a good accuracy if located in open outdoor environment with clear skies. However the accuracy of the estimated position clearly degrades when the line-of-sight from some of the satellites above the horizon to the receiver is obstructed. The position estimation becomes even impossible is the receiver is located indoors.
This dissertation explores a set of methodologies that aim at improving the accuracy and precision of the of the orthometric height based on information from GNSS systems and barometric sensors, in conjunction with forecast data of the atmospheric pressure and temperature. In particular, we explore the fusion techniques that combine the altitude estimation from a GNSS receiver with the altitude estimation derived from the relation between atmospheric pressure and altitude. As a proof of concept, we designed and implemented an Android application which demonstrates the effective operation of the proposed methods in real scenarios. We perform a comparative study which shows that the methods based on GNSS and barometric sensor fusion clearly outperform, in terms of accuracy and precision, the operation of a standalone GPS receiver. Moreover, the proposed methods are able to accurately determine the altitude both in outdoor and indoor environments.
