Low-cost tracking system
View Patent ↗A method of tracking a second electronic device with respect to a first electronic device is disclosed. The method includes transmitting a first waveform of a first frequency along a first fixed path associated with the first device. A second waveform having a frequency based on the first frequency is wirelessly transmitted from the first device to the second device along a first wireless path. The second waveform is wirelessly transmitted from the second device to the first device along a second wireless path. The first and second waveforms are received at the phase comparator circuit. A first phase relationship of the received first waveform is then compared to a second phase relationship of the received re-transmitted waveform. A coordinate of the second device is determined with respect to a reference coordinate based on the comparing.
1. A method of tracking a target device with respect to a tracking device, the method comprising:
generating by a reference signal source in the tracking device, a reference signal;
transmitting the reference signal along a first fixed wired path to first gating logic and along a second fixed wired path to a plurality of receivers;
gating the reference signal by the first gating logic to feed the reference signal to a transmitter only during time intervals when the first gating logic is enabled;
generating, by the transmitter, a wireless reference burst signal representing the gated reference signal, the wireless reference burst signal comprising a plurality of signal bursts during the time intervals when the first gating logic is enabled;
receiving at each of the plurality of receivers, a re-transmitted wireless reference burst signal transmitted from the target device, the re-transmitted second wireless reference burst signal re-transmitted by the target device to the plurality of receivers in response to the target device receiving the wireless reference burst signal;
comparing, with each of the phase comparator circuits, a first phase of the received reference signal to a second phase of the re-transmitted wireless reference burst signal when it is respectively received by each of the phase comparator circuits to generate respective phase comparison signals for each of the phase comparator circuits;
in each of the plurality of receivers, enabling second gating logic during respective second time intervals following detection of the re-transmitted wireless reference burst signal by the respective phase comparator circuits;
in each of the plurality of receivers, gating the respective phase comparison signals by the respective second gating logics in each of the plurality of receivers to feed the respective phase comparison signals to respective state machines of each of the plurality of receivers only during the second time intervals when the respective second gating logics is enabled to generate respective gated phase comparison signals for each of the respective receivers; and
determining, by the state machines for each of the plurality of receivers, a coordinate of the target device in three-dimensional space with respect to a reference coordinate based on the respective gated phase comparison signals generated at each of the respective receivers.
2. The method according to claim 1 wherein determining the coordinate comprises triangulating a position of the target device with respect to the tracking device.
3. The method according to claim 1 wherein the re-transmitted wireless reference burst signal comprises a frequency different from a frequency of the wireless reference burst signal and a phase substantially in-phase with a phase of the wireless reference burst signal.
4. The method according to claim 1 , further comprising receiving additional re-transmitted wireless reference burst signals from additional target devices, the additional re-transmitted wireless reference burst signals each having different frequencies.
5. The method of claim 1 , further comprising rendering a gaming application environment based on the determined coordinate.
6. The method of claim 1 , further comprising directing a medical procedure to a location in a human body based on the determined coordinate.
7. A tracking circuit in an electronic console for detecting the position of a target device, the tracking circuit comprising:
a reference signal generator to generate a reference signal and to transmit the reference signal along a first fixed wired path and along a second fixed wired path;
first gating logic coupled to receive the reference signal from the reference signal generator via the first fixed wired path, and to gate the reference signal to pass the reference signal through the first gating logic only during time intervals when the first gating logic is enabled;
a wireless transmitter coupled to receive the gated reference signal from the first gating logic and to generate a wireless reference burst signal representing the gated reference signal, the wireless reference burst signal comprising a plurality of signal bursts during the time intervals when the first gating logic is enabled;
a plurality of receivers to receive a retransmitted wireless reference burst signal transmitted from the target device, the retransmitted wireless reference burst signal retransmitted by the target device to the plurality of receivers in response to the target device receiving the wireless reference burst signal;
a plurality of phase comparison circuits corresponding to the plurality of receivers, each phase comparison circuit having a first input to receive the reference signal and a second input to receive the retransmitted wireless reference burst signal received by an associated one of the plurality of receivers, each phase comparison circuit comparing a first phase of the reference signal to a second phase of the retransmitted wireless reference burst signal when it is respectively received by each of the phase comparator circuits to generate respective phase comparison signals for each of the phase comparator circuits;
second gating logic in each of the plurality of receivers that are enabled during respective second time intervals following detection of the retransmitted wireless reference burst signal, each second gating logic gating respective phase comparison signals to pass through respective phase comparison signals of each of the plurality of receivers only during the second time intervals to generate respective gated phase comparison signals for each of the plurality of receivers; and
state machines in each of the plurality of receivers to receive the respective gated phase comparison signals and determine a coordinate of the target device in three-dimensional space with respect to a reference coordinated based on the respective gated phase comparison signals.
8. The tracking circuit according to claim 7 wherein the plurality of receivers are user positionable in a non-colinear configuration.
9. The tracking circuit according to claim 8 wherein the transmit circuitry resides at a position coinciding with a position of at least one of the sensor circuits.
10. The tracking circuit according to claim 8 wherein the transmit circuitry resides at a position different from any of the positions of the respective sensor circuits.
11. The tracking circuit according to claim 7 wherein the tracking circuit applies a fixed delay applied to the reference signal, the fixed delay comprising an integer number of waveform cycle times.
12. The tracking circuit according to claim 7 wherein the tracking device is disposed in a video game console.