Magnetic motion tracker with transmitter placed on tracked object

Abstract

The motion of a person is measured in real time using magnetic fields. A magnetic transmitter and a number of magnetic receivers are placed at different points on the person. The transmitter transmits magnetic fields sequentially from three orthogonal coils. The magnetic field is received at each receiver, which consists of three orthogonal coils. The computer resolves the sequential position and orientation coordinates from each receiver into the person's movement, relative to the transmitter, from knowledge of where each receiver is placed on the person. Other embodiments measure the transmitter's position and orientation relative to a fixed location outside of the person. The computer then resolves the position and orientation data into the person's motion relative to the fixed location outside of the person. A second embodiment uses pressure sensitive switches and accelerometers placed on the person's feet and a computer program to find the transmitter's position and orientation relative to a fixed starting location. A third embodiment uses an optical subsystem to find the transmitter's position and orientation relative to a fixed location. A fourth embodiment uses at least one further receiver placed in a fixed location outside of the person to find the transmitter's position and orientation relative to a fixed location. A fifth embodiment utilizes a special magnetic transmitter consisting of a one-axis long range transmitter and a two-axis short range transmitter and two further receivers placed at two fixed locations outside of the person to find the transmitter's position and orientation relative to a fixed location.