32 research outputs found
Spray, Embracing Multimodality
We present Spray, a localization system that compensates
for low accuracy of individual localization measurements by combining measurements from multiple localization modalities
Acoustical Ranging Techniques in Embedded Wireless Sensor Networked Devices
Location sensing provides endless opportunities for a wide range of applications in GPS-obstructed environments;
where, typically, there is a need for higher degree of accuracy. In this article, we focus on robust range
estimation, an important prerequisite for fine-grained localization. Motivated by the promise of acoustic in
delivering high ranging accuracy, we present the design, implementation and evaluation of acoustic (both
ultrasound and audible) ranging systems.We distill the limitations of acoustic ranging; and present efficient
signal designs and detection algorithms to overcome the challenges of coverage, range, accuracy/resolution,
tolerance to Doppler’s effect, and audible intensity. We evaluate our proposed techniques experimentally on
TWEET, a low-power platform purpose-built for acoustic ranging applications. Our experiments demonstrate
an operational range of 20 m (outdoor) and an average accuracy 2 cm in the ultrasound domain. Finally,
we present the design of an audible-range acoustic tracking service that encompasses the benefits of a near-inaudible
acoustic broadband chirp and approximately two times increase in Doppler tolerance to achieve better performance
u-BeepBeep: Low Energy Acoustic Ranging on Mobile Devices
We present u-BeepBeep: a low energy acoustic ranging ser-
vice for mobile phones. -BeepBeep combines the efficacy of the basic BeepBeep ranging mechanism with a light-weight cross-correlation mechanism based on sparse approximation