Network Delay Modeling and Estimation for A-GNSS Supports Over Cellular Networks

Grant Huang and Mikel M. Miller, David Akopian

Peer Reviewed

Abstract:	In recent years, Location Based Services (LBS) enabled by advanced positioning technologies, such as the U.S. global positioning system (GPS) and other global navigation satellite systems (GNSSs), are widely deployed and have gained significant attention from research communities. The U.S. Assisted-GPS (A-GPS) has been proposed to enhance receiver operation in terms of sensitivity and reduced Time-to-First-Fix (TTFF) by providing assistance, such as coarse position, time references, satellite navigation parameters, and other supporting data, from alternative sources using terrestrial networks. Other GNSSs, such as European Galileo, Russian Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), Japanese Quasi-Zenith Satellite System (QZSS), Chinese BeiDou, etc., are also currently being subjected to extensive development aiming to improve satellite visibility and signal availability. As the number of navigation satellites is expected to substantially increase in the future, the assistance delivery will extend to emerging A-GNSS supports as well. As terrestrial network channels are currently required to deliver assistance data, this introduces delays, which may deteriorate assisted operations. Thus, communication network delay models need to be developed and properly studied. Measuring and modeling network delays will help developers generate more realistic scenarios for receiver testing. This paper provides a methodology that can be adopted in network delay modeling for mobile station (MS)-based A-GNSS that is applicable to various simulation environments. It demonstrates a test bed with A-GNSS supports based on Secure User Plane Location (SUPL) architecture using data channels to deliver assistance data on two navigation systems, the U.S. GPS and the Russian GLONASS. In this work, measurement campaigns are conducted and network delay models are derived for various representative distances between assistance servers and receivers over cellular networks, such as third-generation mobile telecommunication (3G), and fourth-generation Long Term Evolution (4G LTE), with the Transmission Control Protocol and the Internet Protocol (TCP/IP) connections.
Published in:	Proceedings of the 2016 International Technical Meeting of The Institute of Navigation January 25 - 28, 2016 Hyatt Regency Monterey Monterey, California
Pages:	932 - 939
Cite this article:	Huang, Grant, Miller, Mikel M., Akopian, David, "Network Delay Modeling and Estimation for A-GNSS Supports Over Cellular Networks," Proceedings of the 2016 International Technical Meeting of The Institute of Navigation, Monterey, California, January 2016, pp. 932-939. https://doi.org/10.33012/2016.13473
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