Method and apparatus for determining the location of a unit using neighbor lists

A method of determining a location of one of a plurality of units, each unit being communicatively coupled to at least some of the other plurality of units, wherein at least some of the plurality of units are reference units, whose locations are known, said method comprising:

• communicating with the units within communication range of the unit to be located;
• establishing a neighbor list for the unit to be located and each of a group of associated units, wherein the associated units are a subset of the plurality of units and include one or more units other than the unit to be located, which are located proximate to the unit to be located, the neighbor list including the list of the units that are in communication range of the respective associated unit;
• identifying any reference units contained in each of the neighbor lists of the unit to be located and the associated units;
• determining an aggregate value corresponding to the number of occurrences of each of the reference units in the neighbor list of the unit to be located and the neighbor lists of each of the associated units;
• and
• determining the location of the unit to be located based upon the known locations of the reference units and the number of identified occurrences of the reference units in the corresponding neighbor lists.