3D-6 New Solution to Air-Data Transmission Using Low-Cost Narrow-Band Ultrasonic Transducers

This paper presents the results of a new solution to air-data transmission for medium distances (10-15 meters) at rates in the order of 10 kbps. The key feature of this work is the use of low-cost narrow-band 40 kHz transducers along with a specially shaped driving signal. Transfer of 128-bit data packets in 15 ms over distances of 10-12 meters with direct line-of-sight were achieved without error in air-channels with limited reflections; thus achieving useful rates at medium range. In addition, a prior air-channel one-symbol response measurement (i.e. aerial channel profiling) can be used to adapt the packet format in order to reduce the reflections effect. Practical tests involving short data packets with bit-position dependant power have given encouraging results. Moreover, contrary to the classical bandwidth widening techniques which rely upon matching networks (i.e. capacitors - inductors), this new solution has the advantage of being exclusively signal processing based.