Method and apparatus for synchronizing multiple magnetic tracking systems

A method of allowing two magnetic tracking systems to operate in the same physical environment, each magnetic tracking system comprising one or more tracking devices, each tracking device containing a plurality of source magnetic coils configured to generate a magnetic field, a receiver containing a plurality of sensor magnetic coils configured to sense the magnetic field and generate magnetic sensor data, a communication link for communicating between the receiver and the one or more tracking devices, and between the first and second magnetic tracking systems, the communication link operating in a manner other than on the generated magnetic field, and a processor, the method comprising;

• determining by the processor from the communication link whether the magnetic tracking system is a first system of the first and second magnetic tracking systems to be active in the same physical environment;
• when the magnetic tracking system is the first of the first and second magnetic tracking systems to be active in the same physical environment:
• assigning, by the processor, the magnetic tracking system a master identification;
• generating and transmitting a synchronization signal corresponding to a series of time slots;
• sequentially instructing, by the processor using the communication link, the one or more tracking devices to each generate a magnetic field during a different time slot in the series of time slots;
• and
• determining by the processor that the other of the first and second magnetic tracking systems has requested a slave identification, and assign the other of the first and second magnetic tracking systems a slave identification from which the other of the first and second magnetic tracking systems can determine further sequential time slots during which the one or more tracking devices in the other of the first and second magnetic tracking systems are to generate a magnetic field;
• when the magnetic tracking system is not the first of the first and second magnetic tracking systems to be active in the same physical environment:
• requesting by the processor from the other of the first and second magnetic tracking systems a slave identification from which further sequential time slots for generating a magnetic field can be determined;
• receiving, using the communication link, from the other of the first and second magnetic tracking systems the synchronization signal;
• and
• instructing, by the processor using the communication link, the one or more tracking devices to sequentially generate a magnetic field during the determined further sequential time slots;
• and
• determining by the processor the position and orientation of the one or more tracking devices on the user relative to the receiver from the magnetic sensor data.

A non-transitory computer readable storage medium having embodied thereon instructions for causing a computing device to execute a method of allowing two magnetic tracking systems to operate in the same physical environment, each magnetic tracking system comprising one or more tracking devices, each tracking device containing a plurality of source magnetic coils configured to generate a magnetic field, a receiver containing a plurality of sensor magnetic coils configured to sense the magnetic field and generate magnetic sensor data, a communication link for communicating between the receiver and the one or more tracking devices on the user, and between the first and second magnetic tracking systems, the communication link operating in a manner other than on the generated magnetic field, and a processor, the method comprising:

• determining by the processor from the communication link whether the magnetic tracking system is a first system of the first and second magnetic tracking systems to be active in the same physical environment,
• when the magnetic tracking system is the first of the first and second magnetic tracking systems to be active in the same physical environment:
• assigning, by the processor, the magnetic tracking system a master identification;
• generating and transmitting a synchronization signal corresponding to a series of time slots;
• sequentially instructing, by the processor using the communication link, the one or more tracking devices to each generate a magnetic field during a different time slot in the series of time slots;
• and
• determining by the processor that the other of the first and second magnetic tracking systems has requested a slave identification, and assign the other of the first and second magnetic tracking systems a slave identification from which the other of the first and second magnetic tracking systems can determine further sequential time slots during which the one or more tracking devices in the other of the first and second magnetic tracking systems are to generate a magnetic field;
• when the magnetic tracking system is not the first of the first and
• second magnetic tracking systems to be active in the same physical environment:
• requesting by the processor from the other of the first and second magnetic tracking systems a slave identification from which further sequential time slots for generating a magnetic field can be determined;
• receiving, using the communication link, from the other of the first and second magnetic tracking systems the synchronization signal, and
• instructing, by the processor using the communication link, the one or more tracking devices to sequentially generate a magnetic field during the determined further sequential time slots;
• and determining by the processor the position and orientation of the one or more tracking devices on the user relative to the receiver from the magnetic sensor data.