In the last years, indoor positioning systems have become an ubiquitous part of smart spaces. The use of coded ultrasonic indoor positioning systems leads to accurate position estimation at reduced cost as the low propagation speed of sound allows the use of analog-to-digital converters at low sampling frequencies. In these systems, coding schemes play a key role in the accuracy and robustness of range estimation and, therefore, in positioning. Consequently, the careful selection and design of the appropriate transmitted waveform should be carried out. This paper introduces two novel multiband waveform synthesis applied to ultrasound-based indoor positioning systems and it compares their performance with current coding schemes used in such systems. Simulations and experimental tests show that some of the proposals effectively deal with several limitations of the previous transmitted waveforms in ultrasonic positioning systems.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.