A novel indoor positioning system based on GPS repeaters in 433 MHZ ISM band

Official URL: https://risc01.sabanciuniv.edu/record=b2486380 _(Table of contents)

Civil Global Positioning System (GPS) based indoor positioning has become a challenging subject owing to the restrictions on the use of GNSS repeaters. The indoor environment is another challenge for positioning due to signal loss from walls and building materials and multipath effect. For these reasons, indoor positioning is still a problem to be solved. A novel GPS repeater and receiver front end are proposed in this thesis to overcome signal coverage and restrictions on the use of GNSS repeaters. The GPS repeater and receiver front ends are designed, implemented, and tested in a real-life scenario. The designed indoor positioning system is based on down-conversion of GPS signals to 433 MHz ISM band on the repeaters. Repeaters amplify and retransmit the down-converted positioning signals indoors in that the allowable output power is increased and the restrictions on the use of GNSS repeaters are circumvented. The increased allowable output power and less path loss at 433 MHz solve the coverage problem extensively. The receiver front end amplifies the positioning signals at 433 MHz, up-converts back to GPS frequency and feeds to an off-the-shelf GPS receiver for decoding the positioning signals. The results of the experiments show that the proposed indoor positioning system may be used to provide indoor positioning by expanding the GPS coverage area indoors. This MSc. thesis is partly supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK) under the grant agreement number 116E752