Wireless position determination

A non-transitory computer-readable storage medium having stored a computer program comprising instructions, which, when executed by a processor, cause the processor to:

• cause an RF emitter to emit a first plurality of RF signals for energizing an RF transponder circuit;
• cause an ultrasound emitter to emit a plurality of ultrasound signals;
• cause the RF transponder circuit configured to reflect the first plurality of RF signals or emit a second plurality of RF signals, the RF transponder circuit comprising circuitry configured to, based on the plurality of ultrasound signals, electrically generate a modulation of the second plurality of RF signals emitted or a modulation of the first plurality of RF signals reflected by the RF transponder circuit, wherein the modulation includes at least one of:
• phase modulation, amplitude modulation, pulse sequence modulation, and code modulation;
• cause an RF detector to detect modulation of the second plurality of RF signals emitted or the modulation of the first plurality of RF signals reflected by the RF transponder circuit;
• and
• determine a position of the RF transponder circuit respective the ultrasound emitter based on a time difference between emission of an ultrasound signal of the plurality of ultrasound signals by the ultrasound emitter and detection by the RF detector of a corresponding modulation in a RF signal of the second plurality of RF signals emitted or a corresponding modulation of a RF signal of the first plurality of RF signals reflected by the RF transponder circuit.

A computer-implemented method for determining a position of an RF transponder circuit, the method comprising:

• causing an RF emitter to emit a first plurality of RF signals for energizing the RF transponder circuit;
• causing an ultrasound emitter to emit a plurality of ultrasound signals;
• causing the RF transponder circuit configured to reflect the first plurality of RF signals or emit a second plurality of RF signals, the RF transponder circuit comprising circuitry configured to, based on the plurality of ultrasound signals, electrically generate a modulation of the second plurality of RF signals emitted or a modulation of the first plurality of RF signals reflected by the RF transponder circuit, wherein the modulation includes at least one of:
• phase modulation, amplitude modulation, pulse sequence modulation, and code modulation;
• causing an RF detector to detect the modulation of the second plurality of RF signals emitted or the modulation of the first plurality of RF signals reflected by the RF transponder circuit;
• and
• determining the position of the RF transponder circuit respective the ultrasound emitter based on a time difference between emission of an ultrasound signal of the plurality of ultrasound signals by the ultrasound emitter and detection by the RF detector of a corresponding modulation in a RF signal of the second plurality of RF signals emitted or a corresponding modulation of a RF signal of the first plurality of RF signals reflected by the RF transponder circuit.