Abstract
Wireless systems already provide time delay and signal strength
measurements and the future may see antenna arrays that provide
directional information. All these may be used for positioning.
Although the statistical accuracy of different positioning methods
is well studied, the systematic error effects, which arise, for
example, from errors in sensor (node) location, network
synchronization, or the path loss model, are not. This study fills
this gap providing a unified error-propagation-law-based tool to
analyze measurement and systematic error effects. The considered
positioning systems, which are compared based on the developed
framework, are the hyperbolic (time-delay-based), direction
finding (DF), received signal strength (RSS), and relative RSS
(RRSS) location systems. The obtained analytical results verify
our intuitive expectations; the hyperbolic methods are sensitive
to errors in network synchronization, RRRS methods to channel
modelling errors, whereas DF methods are rather insensitive to
systematic errors. However, the bias of DF methods is at its
largest if the sensor location error is perpendicular to the line
joining the sensor and the source. If the methods are compared
based on overall accuracy, hyperbolic methods may be preferred in
large sized networks, whereas the DF and RRSS methods may provide
better accuracy in small sized networks. However, RRSS systems
require a dense network in order to provide reliable results.