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Locationing in a Pico
Radio Environment
UNDER CONSTRUCTION!!!!!
GOAL: Goal of Locationing in a Pico radio network is to
provide each and every node in this ad hoc network to with their position
information.
USES of LOCATION INFORMATION: The apparent benefits of this information include
association of sensed data with relevant localities. It provides relative
position and directions for routing and Networking tasks.
ASSUMPTIONS:
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No Central computation unit. That is, there is no
master node that has all the information about the network. the computation
is to be completely done distributedly.
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To determine absolute positions there are nodes in
the network that have their positions preprogrammed. These nodes are called
anchor nodes. They may have their positions by having access to a GPS
receiver or as a result of being programmed during deployment.
METHOD: Our method involves a Two-phase
Locationing.
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Initialize the location estimates. There are
different approaches for initialization. one of them involve treating the
hop counts from anchors a a measure for the distance from those. Using this
information one can achieve a rough topology estimate that can be refined
later. the advantage of this approach is it does not require initial
distance measurements. [Savarese
01] An alternative method involves the use of the error bounds for the
initial estimates [Savvides02]
the contribution of this approach is very simple computation for
initialization.
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Refine the initial estimates
DISTANCE MEASUREMENT TECHNIQUE ALTERNATIVEs :
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Acoustic: High power and suffers from
directionality
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RF Acoustic Hybrid: high power and low
directionality. Easy synch.
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Pure RF measurements. Can be low power but very
prone to channel impairments and multipath effects. Can measure the time of
flight signal strength or angle of arrival methods.
TALKS:
LINKS:
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