Implementation of an Optimized Code Loop for Indoor Positioning

Nabil Jardak, Alexandre Vervisch-Picois, Marc Jeannot, Anca Fluerasu and Nel Samama

Abstract:	Indoor localization based on GNSS repeaters, as described in previous works [1-2], has only been achieved to within a range of few meters. This is due to many error sources among which thermal noise has the greatest impact after multipath error (which is not included in the present paper). But when dealing with indoor positioning, precision should be higher. Therefore, when using the existing GPS signals, one way to satisfy this precision requirement from a signal processing point of view, consists of acting on the tracking loops of the GNSS receiver. Consequently, the present paper will describe new code loop architecture specific to repeater based indoor positioning. Previous studies [3] have shown significant differences of behaviour in the resulting measured noise and accuracy in the code phase jump measurements for different receivers (a MIRA-16 from Martec, including an Aschtech GG-16 board, a PolaRx2 from Septentrio and an R-25 software receiver from NordNav). The complete analysis of these differences leads us to consider the architecture of the code loop and to propose a new structure for improving code phase jump detection and accuracy. Simulations are carried out with the new code loop and the final design is implemented in a NordNav R- 30 software receiver. Experimental results are then obtained that validate the efficiency of the proposed architecture. Note that the improvement allows for a noise reduction coefficient of 5 in the code phase jump detection (from 2.70 meter down to 0.5 meter obtained with simulations).
Published in:	Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007) September 25 - 28, 2007 Fort Worth Convention Center Fort Worth, TX
Pages:	1396 - 1404
Cite this article:	Jardak, Nabil, Vervisch-Picois, Alexandre, Jeannot, Marc, Fluerasu, Anca, Samama, Nel, "Implementation of an Optimized Code Loop for Indoor Positioning," Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, September 2007, pp. 1396-1404.
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