**Field Generator** ======= The field generator (FG) creates a time-varying magnetic field in the working volume of the tracking system. This working volume forms a 25cmx25cmx25cm volume in which an electromagnetic tracking sensor may be used. The FG establishes the magnetic field using eight planar coils, each powered by a single current driver channel described in sections 1-2. The field generator consists of two components - The transmitter coils - The coil housing **Transmitter coil** ---------------- A transmitter coil consists of a square printed circuit board (PCB) with a single winding of 25 turns shared between the top and bottom layers of the board. The coil turn dimensions are precisely known thus allowing precise modelling of the coil in software. Anser utilises eight transmitter coils for the field generator unit. **Coil housing** ------- Each of the eight transmitter coils are secured in a planar housing. The coils are sandwiched between the two halves of the housing. Each coil sits inside a precisely machined recess. The coordinates of each coil recess within the housing is known respect to its origin (center of the housing). The coordinates of each coil are used in the magnetic field model as part of the position and orientation solver.