Multi-purpose TDM Component for GNSS

Axel Garcia-Pena, Olivier Julien, Marco Anghileri, Jean-Jacques Floch, Matteo Paonni

Abstract:	This article proposes a Time-Division-Multiplexing (TDM) technique applied at PRN code level as a signal design solution able to cope with the provision of several functionalities in one signal component: the allocation of the signal to the different functionalities is made at PRN code level. The functionalities targeted in this article are low-complexity acquisition, fast Time-ToFirst-Fix Data (TTFFD), Security Code Authentication (SCA) and, additionally, non-coherent signal processing. The interest of using a TDM component signal design lays on the introduction of just one new component to reduce the complexity to be added to the legacy GNSS satellite payload and to the GNSS receiver. Moreover, a TDM signal design solution presents a great flexibility able to adapt the signal design to the different GNSS strategic directives. The TDM component is constituted of period blocks called short basic blocks and advanced blocks; the introduction of such blocks simplifies the TDM component processing by a GNSS receiver. The TDM component is divided first in a continuous stream of short basic blocks of 20ms, where the short basic blocks are used to provide a signal periodic structure for the acquisition functionality. Then, the short basic blocks are grouped in advanced blocks to provide the signal periodicity for fast TTFFD and SCA. The low-complexity acquisition functionality is provided by the first PRN codes of a short basic block: PRN codes are selected to have a low duration and are always at the same position inside the block. Code Shift Keying Modulation is used to provide the fast TTFFD and the SCA key delivery. An example of application on the Galileo E1 civil signals is presented with different target scenarios or type of users: lowcomplexity user, high performance – no TTFFD, high performance – TTFFD and high dynamics user.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	943 - 962
Cite this article:	Garcia-Pena, Axel, Julien, Olivier, Anghileri, Marco, Floch, Jean-Jacques, Paonni, Matteo, "Multi-purpose TDM Component for GNSS," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 943-962. https://doi.org/10.33012/2018.15890
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