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Session B4: GNSS Integrity and Augmentation Systems

GNSS System Interoperability Evaluation using Geodetic Active Networks
Isai Robles-Bravo, INAOE, Mexico; Rogerio Enriquez-Caldera, INAOE/CRECTEALC, Mexico; Jose Guichard Romero, CRECTEALC/INAOE, Mexico; Sergio Camacho Lara, CRECTEALC, Mexico
Location: Pavilion Ballroom West
Alternate Number 1

GNSS have enabled many countries to provide high precision positioning services. Lately, international agreements for the interoperability of GNSS have allowed improvements of such services. Geodetic active networks around the Globe can be used to implement at the first hand, the systems interoperability and lately, on the second hand, signal interoperability will very soon provide practical real time positioning almost at all time. Multi agent drones, automatic aero ship landings are among many modern uses for the high precision navigation services claimed by the interoperability and therefore, there is the need of methods and algorithms to evaluate GNSS interoperability around some specific areas. Mexico uses the great advantages of the GNSS through its National Geodetic Active Network. Such network provides positioning services in different forms but one of them is under the form of RINEX files every 15 sec.
Here we present a software development whose objective is to test the improvement in positioning due to the system interoperability among the actual satellite systems (GPS, GLONASS, GALILEO and BEIDOU). This development methodology works autonomously to strip all position information provided by each RINEX files and automatically obtains the DOP for the whole constellations of systems in view for each reference point of the active network.
The software implementation uses the RINEX files to find, as first step, all GNSS satellites in the view field for each point of the active network then, as second step all these satellites are shown in maps that are covered by the active network (one map for each GNSS individual system and one final map with all GNSS on view). Later, with the purpose of comparison, the software calculates automatically all DOP’s for each single GNSS as well as the DOP’s for the whole constellation and displays all results. Finally, with the display of all numerical calculations, it is easy to quickly evaluate how the positioning was improved using all GNSS in view as a single system. The impact of the improvement is also evaluated through the software by calculating both point positioning and relative positioning for any given point that is around each reference point of the active network.
Results show that the system interoperability improves from the best single DOP of 1.41 to 0.83 in the average. This work will present the results for point positioning and relative static positioning as another evaluating tools to show how the interoperability improves such calculations as well.
The results are so encouraging, that three future lines of uses are open for this development: i) To provide automatic evaluation every 15 seconds of the obtained precise positioning using system interoperability ii) The methodology used in this development can be applied to any region that has a geodetic active network and iii) to provide an evaluation of the reliability of the complete interoperability when this development is used together with a real time signal interoperable receiver.



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