2 research outputs found
Software-based system for measuring location observables in IEEE 802.11 networks
Several techniques have been proposed for
positioning nodes over IEEE 802.11 networks, but only few
consist in time-based multilateration, mainly due to the protocol
stack not supporting accurate timestamps. One frequent solution
is to develop the hardware required for providing accurate
timestamps. However, this approach tends to slow down the
research and the ulterior deployment of the location techniques,
since the performance of these techniques is bounded to a specific
hardware design. This paper presents a measuring system aimed
at providing location observables that can be used in time-based
multilateration techniques. The system, which follows a software
approach, is based on enhancing the SoftMAC layer of Linux
with location-measuring capabilities. The system is conceived for
supporting any kind of time-based measurements, by adding as
many plugins as measured observables. Two plugins have been
initially developed. The first one computes the round trip time of
a message from a station to an access point and back again to the
station. The second plugin calculates time-differences of arrival
suitable for being used in the passive TDOA technique. This
work provides the definition of the measuring system. Real data
has been collected to test the system. The results indicate that the
measurements provided by the system can be used for location
purposes, i.e. they follow the physical laws in which metrics are
based (e.g. they grow along with the distance between the nodes).Peer Reviewe
Software-based system for measuring location observables in IEEE 802.11 networks
Several techniques have been proposed for
positioning nodes over IEEE 802.11 networks, but only few
consist in time-based multilateration, mainly due to the protocol
stack not supporting accurate timestamps. One frequent solution
is to develop the hardware required for providing accurate
timestamps. However, this approach tends to slow down the
research and the ulterior deployment of the location techniques,
since the performance of these techniques is bounded to a specific
hardware design. This paper presents a measuring system aimed
at providing location observables that can be used in time-based
multilateration techniques. The system, which follows a software
approach, is based on enhancing the SoftMAC layer of Linux
with location-measuring capabilities. The system is conceived for
supporting any kind of time-based measurements, by adding as
many plugins as measured observables. Two plugins have been
initially developed. The first one computes the round trip time of
a message from a station to an access point and back again to the
station. The second plugin calculates time-differences of arrival
suitable for being used in the passive TDOA technique. This
work provides the definition of the measuring system. Real data
has been collected to test the system. The results indicate that the
measurements provided by the system can be used for location
purposes, i.e. they follow the physical laws in which metrics are
based (e.g. they grow along with the distance between the nodes).Peer Reviewe