Researchers at Telecom SudParis are working on a solution to provide indoor continuity for GNSS positioning. The idea is to deploy a minimal transmission infrastructure in order to allow a standard receiver to measure pseudo-ranges and carrier phases, thus leading to an indoor accurate positioning. The infrastructure consists of a few antennas fed through optical fibers with a GNSS-like signal.
Based in Paris, Telecom SudParis is a part of the Institut Mines-Telecom, an education and research institution in the fields of information and communication technology.
To achieve positions accurate to a few decimeters, the locations of the various indoor antennas had to be accurately known. This was achieved with the Spectra Precision FOCUS 8 total station in a local reference frame. In addition, in order to calculate the indoor positioning in WGS84 format, to achieve full compatibility with current outdoor GPS, a Spectra Precision ProMark 800 GNSS receiver was used to link the local reference frame and the GPS. “ The accuracies of the FOCUS 8 and the ProMark 800 and their ease of use were invaluable to us,” said Nel Samama, lead researcher and Professor at the Institut Mines-Telecom.
The International Conference on Indoor Positioning and Indoor Navigation (IPIN) 2012 and 2013 published the first results of the research, and the latest results will soon be published in a paper, “Repealite Based Indoor Positioning System Performance.” The papers propose a new approach to indoor positioning: the repealite system. It aims at providing continuity of the positioning service through the use of GNSS-like signals, thus leading to a single technological means: a GNSS receiver, for both outdoors and indoors. A few error sources have been dealt with in order to reach sub-meter accuracy indoors, among which one has to cite multipath and near-far effects. The paper describes a way to reach indoor sub-meter accuracy and the practical current implementation of the system.