owlps/owlps-positioner/src/fbcm.cc

72 lines
2.7 KiB
C++

/*
* This file is part of the Owl Positioning System (OwlPS).
* OwlPS is a project of the University of Franche-Comte
* (Université de Franche-Comté), France.
*
* Copyright © Université de Franche-Comté 2007-2012.
*
* Corresponding author: Matteo Cypriani <mcy@lm7.fr>
*
***********************************************************************
*
* This software is governed by the CeCILL license under French law and
* abiding by the rules of distribution of free software. You can use,
* modify and/or redistribute the software under the terms of the CeCILL
* license as circulated by CEA, CNRS and INRIA at the following URL:
* http://www.cecill.info
*
* As a counterpart to the access to the source code and rights to copy,
* modify and redistribute granted by the license, users are provided
* only with a limited warranty and the software's authors, the holder
* of the economic rights, and the successive licensors have only
* limited liability.
*
* In this respect, the user's attention is drawn to the risks
* associated with loading, using, modifying and/or developing or
* reproducing the software by the user in light of its specific status
* of free software, that may mean that it is complicated to manipulate,
* and that also therefore means that it is reserved for developers and
* experienced professionals having in-depth computer knowledge. Users
* are therefore encouraged to load and test the software's suitability
* as regards their requirements in conditions enabling the security of
* their systems and/or data to be ensured and, more generally, to use
* and operate it in the same conditions as regards security.
*
* The fact that you are presently reading this means that you have had
* knowledge of the CeCILL license and that you accept its terms.
*
***********************************************************************
*/
#include "fbcm.hh"
#include "stock.hh"
#include "configuration.hh"
Result FBCM::compute(const Request &_request)
{
// If the autocalibration is activated, we have to regenerate the
// Friis indexes each time we calculate a position
if (Configuration::bool_value("positioning.generate-reference-points"))
Stock::update_all_friis_indexes() ;
return TrilaterationAlgorithm::compute(_request) ;
}
float FBCM::estimate_distance(const Measurement &measurement)
{
double constant_term = make_constant_term(measurement) ;
const float &average_dbm = measurement.get_average_dbm() ;
const AccessPoint *ap = measurement.get_ap() ;
return pow(10, (constant_term - average_dbm) /
(10 * friis_index(ap))) ;
}
inline float FBCM::friis_index(const AccessPoint *const ap) const
{
return ap->get_friis_index() ;
}