20,842 research outputs found
Device-free Localization using Received Signal Strength Measurements in Radio Frequency Network
Device-free localization (DFL) based on the received signal strength (RSS)
measurements of radio frequency (RF)links is the method using RSS variation due
to the presence of the target to localize the target without attaching any
device. The majority of DFL methods utilize the fact the link will experience
great attenuation when obstructed. Thus that localization accuracy depends on
the model which describes the relationship between RSS loss caused by
obstruction and the position of the target. The existing models is too rough to
explain some phenomenon observed in the experiment measurements. In this paper,
we propose a new model based on diffraction theory in which the target is
modeled as a cylinder instead of a point mass. The proposed model can will
greatly fits the experiment measurements and well explain the cases like link
crossing and walking along the link line. Because the measurement model is
nonlinear, particle filtering tracing is used to recursively give the
approximate Bayesian estimation of the position. The posterior Cramer-Rao lower
bound (PCRLB) of proposed tracking method is also derived. The results of field
experiments with 8 radio sensors and a monitored area of 3.5m 3.5m show that
the tracking error of proposed model is improved by at least 36 percent in the
single target case and 25 percent in the two targets case compared to other
models.Comment: This paper has been withdrawn by the author due to some mistake
Cooperative Relative Positioning of Mobile Users by Fusing IMU Inertial and UWB Ranging Information
Relative positioning between multiple mobile users is essential for many
applications, such as search and rescue in disaster areas or human social
interaction. Inertial-measurement unit (IMU) is promising to determine the
change of position over short periods of time, but it is very sensitive to
error accumulation over long term run. By equipping the mobile users with
ranging unit, e.g. ultra-wideband (UWB), it is possible to achieve accurate
relative positioning by trilateration-based approaches. As compared to vision
or laser-based sensors, the UWB does not need to be with in line-of-sight and
provides accurate distance estimation. However, UWB does not provide any
bearing information and the communication range is limited, thus UWB alone
cannot determine the user location without any ambiguity. In this paper, we
propose an approach to combine IMU inertial and UWB ranging measurement for
relative positioning between multiple mobile users without the knowledge of the
infrastructure. We incorporate the UWB and the IMU measurement into a
probabilistic-based framework, which allows to cooperatively position a group
of mobile users and recover from positioning failures. We have conducted
extensive experiments to demonstrate the benefits of incorporating IMU inertial
and UWB ranging measurements.Comment: accepted by ICRA 201
Communication Subsystems for Emerging Wireless Technologies
The paper describes a multi-disciplinary design of modern communication systems. The design starts with the analysis of a system in order to define requirements on its individual components. The design exploits proper models of communication channels to adapt the systems to expected transmission conditions. Input filtering of signals both in the frequency domain and in the spatial domain is ensured by a properly designed antenna. Further signal processing (amplification and further filtering) is done by electronics circuits. Finally, signal processing techniques are applied to yield information about current properties of frequency spectrum and to distribute the transmission over free subcarrier channels
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