Patent ID: 7123925

Claim:
A method of estimating the location of a device within a network of devices each of which forms a node of the network such that the device may communicate with any other node in the network either directly or indirectly via intermediate devices, the device within the network with which the device may communicate directly being referred to as a neighbouring node, the method including the steps of: obtaining information specifying the location or estimated location of one or more of the neighbouring node or nodes; measuring the distance from the device to said one or more neighbouring nodes; iteratively modifying an estimated location of the device, so as to reduce an error function based on the inconsistency between the estimated location of the device and the location or estimated location of the one or more neighbouring nodes, as determined from the obtained information specifying the location or estimated location of the one or more neighbouring nodes, on the one hand and the measured distance or distances from the device to the one or more neighbouring nodes on the other hand; and periodically determining whether or not to implement a reset procedure, on the basis of whether or not certain conditions are met, by which the estimated location of the device is reset to a new location in a manner which does not seek to reduce the error function in respect of the new location relative to the immediately preceding estimated location of the device, whereby the device can avoid getting its estimated location stuck in a position corresponding to a local minimum value of the error function.