Patent attributes
A calibration system for a position determination system, the calibration system includes, in one embodiment, a calibration transmitter producing a calibration signal, a plurality of calibration receivers for receiving the calibration signal, each of the calibration receivers of the plurality of calibration receivers having a respective known calibration receiver position, and each of the calibration receivers of the plurality of calibration receivers including means for receiving a first signal characteristic of said calibration signal, means for receiving a second signal characteristic of said calibration signal, and a comparison unit for comparing said first signal characteristic and said second signal characteristic of said calibration signal to generate a calibration comparison result. In various embodiments, signal comparisons may be differences between electric and magnetic field phase or may utilize signal amplitude differences. A system utilizing a receiver and multiple transmitter locations is disclosed. Position may be determined using existing wiring.