This study aims at investigating a central mounted Indoor Positioning System based onBluetooth RSSI values and Kalman filtering where the Bluetooth module is mounted on arotating arm around an axle. The purpose is to investigate how the length of the arm and therotational speed influence on the possible positioning accuracy of the artefact. As requested bythe company Combitech AB, the artefact will also be evaluated whether the design is areasonable alternative to de most common Bluetooth based Indoor Positioning Systems. Thecase study is performed using design science as an artefact is developed and evaluated. Theartefact is tested in a predetermined test environment, in this case an office room. In the testenvironment, measurements will be realized on the different iterations of the artefact. Theresult of the study is the achieved positioning accuracy for the artefact in two and threedimensions. Linear equations describing the relationship between the length of the arm andthe achieved accuracy of the artefact will also be proposed. The best accuracy achieved in twodimensions was 510 centimeters. The best achieved accuracy in three dimensions was 730 centimeters. The observed relationship between the length of the arm and the uncertainty ofthe trilaterated position is that when the length of the arm increases the uncertainty decreasesin both two and three dimensions.