System for processing asynchronous sensor data

• US 9,596,666 B1
• Filed: 12/11/2015
• Issued: 03/14/2017
• Est. Priority Date: 12/11/2015
• Status: Active Grant

• Current Assignee: Uatc, LLC (Uber Technologies, Inc.)
• Original Assignee: Uber Technologies, Inc.
• Inventors: Strother, Daniel, Sibenac, Mark, Tascione, Daniel, Jones, Morgan, Brindza, Jordan
• Primary Examiner(s): Marcelo, Melvin
• Application Number:
  US14/967,178
• Time in Patent Office: 459 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

A sensor synchronization system for a sensor apparatus. The system synchronizes a local clock signal with an external timing signal. For example, the external timing signal may correspond to a pulse per second (PPS) signal received from a global positioning system (GPS) receiver. The system further generates a plurality of sensor pulses that are each offset in phase relative to the local clock signal by a respective amount. The system then receives sensor data from the sensor apparatus, and determines a timing of the sensor data in relation to the local clock signal based at least in part on the plurality of sensor pulses.

Claims

1. A method of acquiring data from a first sensor apparatus, the method comprising:

synchronizing a local clock signal with an external timing signal;

dividing a clock cycle of the local clock signal into a plurality of timing intervals, wherein the number of timing intervals is based at least in part on a framerate or resolution of a second sensor apparatus;

generating a plurality of sensor pulses based at least in part on framerates or resolutions of each of a plurality of sensors of the first sensor apparatus, wherein each of the plurality of sensor pulses are aligned with a respective one of the timing intervals;

receiving sensor data from the first sensor apparatus; and

determining a timing of the sensor data in relation to the local clock signal based at least in part on the plurality of sensor pulses.

2. The method of claim 1, wherein the timing of the sensor data corresponds to a time at which the sensor data was captured by the first sensor apparatus.

3. The method of claim 2, wherein the determining comprises:

determining which of the plurality of sensor pulses coincides with the time at which the sensor data was captured.

4. The method of claim 1, further comprising:

receiving the external timing signal from a global positioning system (GPS) receiver.

5. The method of claim 4, wherein the external timing signal is a pulse per second (PPS) signal.

6. The method of claim 1, wherein the second sensor apparatus corresponds to a machine vision camera for an autonomous vehicle.

7. The method of claim 6, further comprising:

generating a three-dimensional sensor image for navigating the autonomous vehicle based at least in part on the sensor data received from the first sensor apparatus.

8. The method of claim 1, wherein the first sensor apparatus includes at least one of an inertial measurement unit (IMU), a rotary encoder, or radar.

9. A sensor synchronization system, comprising:

clock synchronization circuitry to synchronize a local clock signal with an external timing signal;

a memory that stores instructions for acquiring data from a first sensor apparatus; and

one or more processors that, upon executing the instructions, cause the sensor synchronization system to;

divide a clock cycle of the local clock signal into a plurality of timing intervals, wherein the number of timing intervals is based at least in part on a framerate or resolution of a second sensor apparatus;

generate a plurality of sensor pulses based at least in part on framerates or resolutions of each of a plurality of sensors of the first sensor apparatus, wherein each of the plurality of sensor pulses are aligned with a respective one of the timing intervals;

receive sensor data from the first sensor apparatus; and

determine a timing of the sensor data in relation to the local clock signal based at least in part on the plurality of sensor pulses.

10. The sensor synchronization system of claim 9, wherein the clock synchronization circuitry comprises a phase-locked loop (PLL).

11. The sensor synchronization system of claim 9, wherein the timing of the sensor data corresponds to a time at which the sensor data was captured by the first sensor apparatus.

12. The sensor synchronization system of claim 11, including further instructions to:

determining which of the plurality of sensor pulses coincides with the time at which the sensor data was captured.

13. The sensor synchronization system of claim 9, wherein the clock synchronization circuitry receives the external timing signal from a global positioning system (GPS) receiver.

14. The sensor synchronization system of claim 13, wherein the external timing signal is a pulse per second (PPS) signal.

15. The sensor synchronization system of claim 9, wherein the number of timing intervals is based at least in part on a framerate or resolution of a machine vision camera for an autonomous vehicle.

16. The sensor synchronization system of claim 15, including further instructions to:

generate a three-dimensional sensor image for navigating the autonomous vehicle based at least in part on the sensor data received form the first sensor apparatus.

17. A non-transitory computer-readable storage medium containing instructions that, when executed by a processor of a sensor synchronization system, causes the sensor synchronization system to:

synchronize a local clock signal with an external timing signal;

divide a clock cycle of the local clock signal into a plurality of timing intervals, wherein the number of timing intervals is based at least in part on a framerate or resolution of a second sensor apparatus;

generate a plurality of sensor pulses based at least in part on framerates or resolutions of each of a plurality of sensors of a first sensor apparatus, wherein each of the plurality of sensor pulses are aligned with a respective one of the timing intervals;

receive sensor data from the first sensor apparatus; and

determine a timing of the sensor data in relation to the local clock signal based at least in part on the plurality of sensor pulses.