Active Bat is a low-power,
wireless
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The mos ...
indoor
location
In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ...
system accurate up to 3
cm. It is based on a principle of
trilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth ( geopositioning).
When more than three distances are involved, it may be called multilateration, for ...
, and relies on multiple
ultrasonic
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies f ...
receivers embedded in the ceiling and measures
time-of-flight
Time of flight (ToF) is the measurement of the time taken by an object, particle or wave (be it acoustic, electromagnetic, etc.) to travel a distance through a medium. This information can then be used to measure velocity or path length, or as a w ...
to them.
Active Bat is an
indoor localization system which gives an accuracy within centimeters. This is a range based technique, which works by finding the distance to minimum of three reference nodes and then using
multilateration Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth ( geopositioning).
When more than three distances are involved, it may be called multilateration, for ...
technique to find the exact position. The distance to reference nodes is find out using the
time of arrival Time of arrival (TOA or ToA) is the absolute time instant when a radio signal emanating from a transmitter reaches a remote receiver.
The time span elapsed since the time of transmission (TOT or ToT) is the ''time of flight'' (TOF or ToF).
Time diff ...
of ultrasonic signals from the reference nodes.
See also
*
Sentient computing
Sentient computing is a form of ubiquitous computing which uses sensors to perceive its environment and react accordingly. A common use of the sensors is to construct a world model which allows location-aware or context-aware applications to be c ...
*
Ubiquitous computing
Ubiquitous computing (or "ubicomp") is a concept in software engineering, hardware engineering and computer science where computing is made to appear anytime and everywhere. In contrast to desktop computing, ubiquitous computing can occur using ...
References
*
External links
The Bat Systemat Cambridge Computer Laboratory Digital Technology Group
Ultrasound
Navigational equipment
University of Cambridge Computer Laboratory
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