http://hdl.handle.net/2117/1129 2013-05-21T05:02:49Z http://hdl.handle.net/2117/3014 Title: Open source precise point positioning with GNSS data structures and the GPSTk Authors: Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume 2009-06-12T06:53:05Z http://hdl.handle.net/2117/2650 Title: Direct determination of electron density profiles from GNSS occulttion data Authors: Aragón Ángel, María Ángeles; Hernández Pajares, Manuel; Miguel Juan, Miguel; Sanz Subirana, Jaume; Ramos Bosch, Pedro 2009-03-12T08:12:22Z http://hdl.handle.net/2117/2617 Title: Improved Abel transform inversion: application to COSMIC/FORMOSAT-3 ionospheric occultations Authors: Aragón Ángel, María Ángeles; Hernández Pajares, Manuel; Miguel Juan, Miguel; Sanz Subirana, Jaume; Altadill, David; Liou, Yuei­An; Lee, Chien­Chih 2009-03-02T11:36:47Z http://hdl.handle.net/2117/2615 Title: The User Domain Integrity Assessment Technique Authors: Sanz Subirana, Jaume; Ramos Bosch, Pedro; Aragón Ángel, María Ángeles; Ciollaro, Massimo; Toran, Felix; Ventura Travesset, Javier; López, C. Abstract: This paper presents a study performed for the detailed analysis of user domain and pseudorange integrity on Satellite Based Augmentation Systems. Experimental data of EGNOS pre-operational service was used for some specific tests, aiming at identifying for instance the good reaction of the EGNOS check-set subsystem and the way pseudorange errors are translated into the user domain. From this analysis, a new technique for User Domain Integrity Assessment (UDIA) was developed. With the UDIA technique, the integrity is checked for all possible geometries from 4 to all satellites in view from a network of stations. When no MI is found (from a wide and sufficiently dense stations network), it can be assured that the system is safe, and it becomes the best experimental guarantee at the User Domain Level. If a NMI/MI appears from any geometry of satellites from the stations in the network, thence a search algorithm is applied to identify the satellite, or combinations of satellites, responsible of such NMI/MIs (i.e., their exclusion leads to the disappearance of the NMI/MIs). After identifying such satellites, the reaction of the EGNOS Check Set (CS) is evaluated by checking if they were set as DU or NM within a predefined time interval after the NMI/MI is detected. 2009-03-02T11:17:56Z http://hdl.handle.net/2117/2614 Title: High accuracy positioning using carrier-phases with the opensource GPSTK software Authors: Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Miguel, J.; Sanz Subirana, Jaume 2009-03-02T10:59:57Z http://hdl.handle.net/2117/2613 Title: Mejora de la transformada inversa de Abel: aplicación ocultaciones ionosféricas de COSMIC/FORMOSAT-3 Authors: Aragón Ángel, María Ángeles; Hernández Pajares, Manuel; Miguel, J.; Sanz Subirana, Jaume 2009-03-02T09:42:21Z http://hdl.handle.net/2117/2101 Title: The GPS Toolkit: world class open source software tools for the GNSS research community Authors: Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume Abstract: The ”GPS Toolkit” (GPSTk) project is an advanced GNSS Open Source Software (GOSS) suite initiated by the Applied Research Laboratories of the University of Texas (ARL:UT), aiming to provide a world class GNSS library computing suite to the satellite navigation community. The objective of this work is to show how the GPSTk suite may be used to rapidly and easily develop, implement and test advanced GNSS data processing applications in a flexible way. The main characteristics and modules of the GPSTk are also presented, as well as the current trends in its development. Results from the GNSS data processing carried out with the examples introduced in this work are shown, as well as a brief comparison with an established GPS software package such as BRUS. 2008-06-19T11:01:26Z http://hdl.handle.net/2117/2099 Title: Rapid Open Source GPS software development for modern embedded systems:using the GPSTk with the Gumstix Authors: Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume Abstract: This work shows how the combination of GPS Open Source Software (GOSS) and advanced full function miniature computers (FFMC) allows rapid development, implementation and testing of advanced embedded GNSS data processing applications in a flexible way. In this regard, our tools of choice are the “GPS Toolkit” (GPSTk), and a modern, high power embedded platform such as the “Gumstix” computer boards. 2008-06-17T11:27:51Z http://hdl.handle.net/2117/970 Title: ESTB performance against lossing satellites (first results) Authors: Sanz Subirana, Jaume; Prats Menéndez, Xavier; Farnworth, Richard; Soley, Santiago Abstract: The EGNOS System Test Bed (ESTB) is the EGNOS prototype which has been broadcasting a Signal in Space since February 2000. Accuracy, integrity, continuity and availability are the main concepts in this European component of the Satellite Based Augmentation System which is designed to support en route through precision approach aircraft navigation. In this work, for the first half of the year of 2002, we study the ESTB performance in fixed sites in Barcelona, and we analyze how this performance is affected when losing a single ESTB monitored satellite. The data set involves a 24 hours weekly measurements collected in two fixed sites (UPC1 and UPC2), from January to August 2002. In particular, the number of Loss of Integrity events (LOI) and the degradation of the Vertical Position Error percentile and the APV-II availability are analyzed. As the main results, two satellites have been identified which loss could have produced a large number of LOIs (up to hundreds) in two particular days before the ESTB update of April 16th 2002. The improvement in the ESTB performance after such update is also reported. 2007-05-10T09:08:22Z http://hdl.handle.net/2117/969 Title: Study of several interpolation schemes to provide ionospheric corrections for navigation Authors: Orús Pérez, Raül; García Fernández, Miquel; Prats Menéndez, Xavier; Hernández Pajares, Manuel; Juan, Miguel Abstract: Since the development of space based geodesic techniques, the increasing of the positioning accuracy has been a major goal. In this context, the effect of the ionosphere has been a key issue to be taken into account to improve the navigation results obtained using several types of receivers: from dual frequency phase receivers at distances greater than tens of kilometres of the nearest fixed site to single frequency code receivers. To overcome this problem, it is necessary either an accurate modelling of the ionosphere at the fixed stations and an optimum interpolation scheme for the rover receiver. This approach is either valid for single frequency users or rovers using dual frequency phase receiver. The current work studies the performance of different interpolation schemes such as linear interpolation and kriging, which can be implemented in a rover receiver in order to interpolate either the Slant Total Electron Content (from now on STEC) or the Double Differenced STEC from the transmitted corrections that are computed at the fixed stations. 2007-05-10T09:02:21Z http://hdl.handle.net/2117/968 Title: SBAS ionospheric performance evaluation tests Authors: Prats Menéndez, Xavier; Orús Pérez, Raül; Sanz Subirana, Jaume; Farnworth, Richard; Soley, Santiago Abstract: Satellite Based Augmentation systems (SBAS) provide to Global Navigation Satellite Systems (GNSS) users with an extra set of information, in order to enhance accuracy and integrity levels of GNSS stand alone positioning. In this context, different test methods to analyze the ionospheric corrections performance are presented. The first set of tests involves two of the ionospheric calculations that are applied daily to the Global Ionospheric Maps (GIM), computed by the IGS Associate Analysis Centers: a TEC TOPEX comparison test and the STEC variations test. The second family of tests provides two very accurate analyses based on large-baselines ambiguity resolution techniques giving comparisons for absolute STEC and double differenced STEC determinations. Those four analyses have been applied using EGNOS System Test Bed (ESTB) data showing some satellite dependent biases. 2007-05-10T09:00:28Z http://hdl.handle.net/2117/828 Title: Basic Research Utilities for SBAS (BRUS) Authors: Prats Menéndez, Xavier; Orús Pérez, Raül; Sanz Subirana, Jaume; Farnworth, Richard; Soley, Santiago Abstract: The software package BRUS (Basic Research utilities for SBAS) to process WAAS and EGNOS data is being developed by gAGE/UPC. Some of the main characteristics of BRUS are its architecture design and functionalities that allow to obtain huge information for the different error source components (satellite coordinates, clocks, ionospheric corrections,...), providing wide possibilities for the SBAS performance analysis in both, SIS and position domain. As an application, the performance of the EGNOS System Test Bed (ESTB) during 2002 is analyzed; using data sets collected in the ESTB Data Collection and Evaluation campaigns of EUROCONTROL (the European Organization for the Safety of Air Navigation). As an extension of BRUS, a Global Performance SBAS Monitoring Tool using public domain GPS networks data is going to be developed. 2007-05-02T10:50:39Z