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<p><span class="caps">GPS</span> systems are being used more and more by home users and therefore new problems are being raisen. One of <span class="caps">GPS</span> problems is that it doesn&#8217;t work under a roof. Therefore another means of calculating your position indoors are in need.</p>

<p><a href="http://immi.inesc-id.pt/person.php?person_id=14">Pedro Sousa</a> and <a href="http://immi.inesc-id.pt/person.php?person_id=1">Joaquim Jorge</a> are developing an algorithm to calculate the probability of being somewhere in the building. Their system only relies on several APs located around the building. It needs 3 AP or more, so this system won&#8217;t be used in small houses, but in large buildings like university or large companies facilities. </p>

<p>For now the system is giving great results ( Average error &#8804; 6 meters in 88% of cases ) but they are still working in order to improve it.</p>