Granted Patent B1

US 10,782,782 · App. 16/515,066 · Granted Sep 22, 2020

Inventors: Riccardo DeSalvo (Pasadena, CA); Giuseppe Castaldi (Apice, IT); Andrea Cusano (Caserta, IT); Vincenzo Galdi (Benevento, IT); Paolo Mattera (Benevento, IT); Roberto Parente (Cerreto Sannita, IT); Fereydoun Daneshgaran (La Crescenta, CA); Joseph Minh Tien (Alhambra, CA); Dustin Krogstad (Chino, CA)

Assignee: Facebook Technologies, LLC

G06F3/014G01S13/767

Abstract

Claims (64)

1. An apparatus comprising:

at least one radar device that transmits a frequency-modulated radar signal to a plurality of transponders located on a wearable device worn by a user; and

a processing device communicatively coupled to the radar device, wherein the processing device:

directs at least one of the plurality of transponders to be in an active state that enables the transponder to receive and transmit signals;

detects, while the transponder is in the active state, a signal returned to the radar device from the transponder in response to the frequency-modulated radar signal;

calculates, based at least in part on the returned signal, a distance between the transponder and the radar device; and

determines, based at least in part on the distance between the transponder and the radar device, a current physical location of at least a portion of the user.

2. The apparatus of claim 1 , further comprising an additional wearable device that:

is worn by the user; and

secures the radar device.

3. The apparatus of claim 1 , wherein the processing device:

directs the transponder to be in the active state for a certain period of time; and

after the certain period of time has lapsed, directs the transponder to enter an inactive state that prevents the transponder from transmitting frequency-modulated radar signals.

4. The apparatus of claim 3 , wherein a duration of the certain period of time is sufficient for at least:

the transponder to receive the frequency-modulated radar signal from the radar device; and

the transponder to transmit the returned signal to the radar device.

5. The apparatus of claim 3 , wherein the processing device directs the transponder to continuously cycle between being in the active state for the certain period of time and being in the inactive state for an additional period of time.

6. The apparatus of claim 3 , wherein the processing device:

receives, from an artificial reality system that provides virtual content to the user, a request to determine the current physical location of the portion of the user; and

directs the transponder to enter the active state in response to the request.

7. The apparatus of claim 3 , wherein the processing device:

directs at least one additional transponder within the plurality of transponders to be in the inactive state while the transponder is in the active state; and

directs the additional transponder to enter the active state at the same time the transponder enters the inactive state.

8. The apparatus of claim 1 , wherein:

the transponder harvests energy from at least one ambient energy source prior to entering the active state; and

the transponder transmits the returned signal to the radar device using the harvested energy rather than energy provided by a power supply.

9. The apparatus of claim 1 , wherein the processing device calculates the distance between the transponder and the radar device based at least in part on extracting, from the returned signal, a beat frequency that:

corresponds to a difference between a frequency of the frequency-modulated radar signal and a frequency of the returned signal; and

is proportional to the distance between the transponder and the radar device.

10. The apparatus of claim 1 , wherein:

the processing device further passes the current physical location of the portion of the user to an artificial reality system that provides virtual content to the user; and

the artificial reality system modifies at least one virtual component of the artificial reality system to account for the current physical location of the portion of the user.

11. A radar system comprising:

a wearable device that:

is worn by a user of an artificial reality system; and

secures a plurality of transponders;

at least one radar device that transmits a frequency-modulated radar signal to the plurality of transponders; and

a processing device communicatively coupled to the radar device, wherein the processing device:

directs at least one of the plurality of transponders to be in an active state that enables the transponder to receive and transmit signals;

detects, while the transponder is in the active state, a signal returned to the radar device from the transponder in response to the frequency-modulated radar signal;

calculates, based at least in part on the returned signal, a distance between the transponder and the radar device; and

determines, based at least in part on the distance between the transponder and the radar device, a current physical location of at least a portion of the user.

12. The radar system of claim 11 , wherein the processing device:

directs the transponder to be in the active state for a certain period of time; and

after the certain period of time has lapsed, directs the transponder to enter an inactive state that prevents the transponder from transmitting frequency-modulated radar signals.

13. The radar system of claim 12 , wherein the processing device directs the transponder to enter the inactive state by directing the transponder to disable at least a portion of the functionality of the transponder.

14. The radar system of claim 13 , wherein disabling the portion of the functionality of the transponder reduces a power consumption level of the transponder while in the inactive state by at least a certain amount compared to a power consumption level of the transponder while in the active state.

15. The radar system of claim 11 , wherein the processing device directs each of the plurality of transponders to switch between the active state and the inactive state at various points in time.

16. The radar system of claim 15 , wherein the processing device identifies a particular transponder within the plurality of transponders that returned a signal to the radar device based at least in part on which transponders are in the active state at a point in time at which the signal was received by the radar device.

17. The radar system of claim 11 , wherein the processing device:

establishes, with the transponder, a separate communication channel that is not used by at least a portion of the other transponders within the plurality of transponders; and

directs the transponder to be in the active state via the separate communication channel.

18. The radar system of claim 11 , further comprising an additional wearable device that:

is worn by the user; and

secures the radar device.

19. The radar system of claim 18 , wherein:

the wearable device comprises an artificial reality glove; and

the additional wearable device comprises an artificial reality helmet.

20. A method comprising:

transmitting, from at least one radar device, a frequency-modulated radar signal to a plurality of transponders located on a wearable device worn by a user; and

directing at least one of the plurality of transponders to be in an active state that enables the transponder to receive and transmit signals;

detecting, while the transponder is in the active state, a signal returned to the radar device from the transponder in response to the frequency-modulated radar signal;

calculating, based at least in part on the returned signal, a distance between the transponder and the radar device; and

determining, based at least in part on the distance between the transponder and the radar device, a current physical location of at least a portion of the user.

Assignments (2)

Continuity (1)

Cited By (15)

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