A POSITIONING DEVICE AND A SYSTEM FOR DETECTING THE POSITION OF SUCH A DEVICE

摘要

The present invention relates to a positioning device 10, 20, 30, 40, 50 arranged in relation to a target area inside a body. The device comprises at least one transmitter 11, 21-22, 32, 41, 51, and each transmitter is arranged to emit an electromagnetic signal. The electromagnetic signal is adapted to propagate with a wavelength in the body so that a phase difference and/ or an amplitude difference of said electromagnetic signal in at least three positions (18) is detectable by a receiver (19) for tracking variations of a position of the positioning device relative to the receiver. The wavelength is selected so that a distance from the transmitter to each of the three positions is within the same integer number of wavelengths of the electromagnetic signal. Each transmitter is connectable to an externally arranged control unit (15), where said electromagnetic signal of each transmitter is generated before transmission. Each transmitter and receiver preferably operates in a near field region. The invention also relates to a system for tracking the position of a target area using a positioning device.