摘要 |
A method and system of operating a location system to locate objects in space, such as medical instruments (16) within the body of a patient is presented. The method includes cyclically actuating transmitters (10a, 10b, 10c) in a fixed frame of reference for the transmission of magnetic fields to a plurality of sensing units (54a, 54b, 54c). The sensing units detect characteristics of the fields during actuation sequences for determining location. At least one transmitter may be actuated during at least some of the cycles in a plural-value actuation sequence to provide a field with different field strengths during a sequence of plural sensing intervals, and with a progressively varying field strength value during transition intervals between the sensing intervals. |