Orientation estimation based on backward-forward bayesian filtering

• US 9,769,620 B1
• Filed: 01/19/2017
• Issued: 09/19/2017
• Est. Priority Date: 05/13/2016
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Khider, Mohammed, Williams, Brian, Le Grand, Etienne, Robertson, Patrick
• Primary Examiner(s): Sarwar, Babar
• Application Number:
  US15/409,890
• Time in Patent Office: 243 Days
• Field of Search: 4554041, 4554121-4142, 455 411- 412, 455418-4221, 4554561, 4554562, 4554563, 455457, 455566, 4555521, 4555502
• CPC Class Codes: G01C 19/00 Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
• CPC Class Codes: G01C 25/005 initial alignment, calibration or starting-up of inertial devices
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/025 using location based information parameters
• CPC Class Codes: H04W 4/026 using orientation information, e.g. compass
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings

Abstract

A system includes one or more processors, and data storage configured to store instructions that, when executed by the one or more processors, cause the system to perform functions. In this example, the functions include receiving sensor data that is collected by one or more sensors of a device over one or more locations and over a time period. Further, in the present example, the functions also include determining location estimates of the device by performing filtering of the sensor data to determine offsets for a least one sensor providing sensor data. The filtering is an iterative process of filtering control input data to determine the sensor bias based on data from a second sensor of the at least two sensors and adjusting the set of sensor data based on the determined bias.

Claims

1. A method comprising:

receiving a set of sensor data, wherein the set of sensor data comprises data from at least two movement sensors of a device and wherein the sensor data corresponds to a movement of the device, and wherein the movement sensors include at least one of a gyroscope, a magnetometer, and an accelerometer;

communicating at least a subset of the set of sensor data to a remote server;

determining a sensor bias for a first sensor of the at least two movement sensors by iteratively;

filtering data from a first sensor of the two movement sensors a first time to determine the sensor bias based on data from a second sensor of the at least two movement sensors, and wherein the filtering of the data the first time filters the data in one of a forward-in-time direction or a backward-in-time direction;

adjusting the set of sensor data based on the determined bias;

filtering the data from the first sensor a second time to revise the determined sensor bias, wherein the filtering is performed based on the data from the second sensor of the at least two movement sensors, and wherein the filtering of the data the second time filters the data in the other one of the forward-in-time direction or the backward-in-time direction;

adjusting the set of sensor data based on the revised determined bias; and

storing the adjusted sensor data; and

supplementing the adjusted sensor data based on calculations performed by the server.

2. The method of claim 1, wherein:

the filtering of the set of sensor data the first time is further based on data from a third sensor of the at least two sensors; and

the filtering of the set of sensor data the second time is further based on data from a third sensor of the at least two sensors.

3. The method of claim 2, wherein the third sensor is one of a magnetometer and an accelerometer.

4. The method of claim 1, wherein the first sensor is a gyroscopic sensor and wherein the second sensor is one of a magnetometer and an accelerometer.

5. The method of claim 1, wherein the filtering is performed with a Bayesian filter.

6. The method of claim 1, wherein the filtering of the set of sensor data the first time filters the data in a forward-in-time direction and the filtering of the set of sensor data the second time filters the data in a backward-in-time direction.

7. The method of claim 1, wherein the set of sensor data is received from a mobile device and wherein the method further comprises communicating the revised determined bias in response to the sensor bias converging.

8. A non-transitory computer-readable medium having stored thereon program instructions that when executed by one or more processors cause performance of functions in connection with a computing device, the functions comprising:

receiving a set of sensor data, wherein the set of sensor data comprises data from at least two movement sensors of a device and wherein the sensor data corresponds to a movement of the device, and wherein the movement sensors include at least one of a gyroscope, a magnetometer, and an accelerometer;

communicating at least a subset of the set of sensor data to a remote server;

determining a sensor bias for a first sensor of the at least two movement sensors by iteratively;

filtering data from a first sensor of the two movement sensors a first time to determine the sensor bias based on data from a second sensor of the at least two movement sensors, and wherein the filtering of the data the first time filters the data in one of a forward-in-time direction or a backward-in-time direction;

adjusting the set of sensor data based on the determined bias;

filtering the data from the first sensor a second time to revise the determined sensor bias, wherein the filtering is performed based on the data from the second sensor of the at least two movement sensors, and wherein the filtering of the data the second time filters the data in the other one of the forward-in-time direction or the backward-in-time direction;

adjusting the set of sensor data based on the revised determined bias; and

storing the adjusted sensor data; and

supplementing the adjusted sensor data based on calculations performed by the server.

9. The computer-readable medium of claim 8, wherein:

the filtering of the set of sensor data in the first direction to determine the sensor bias is further based on data from a third sensor of the at least two sensors; and

the filtering of the set of sensor data in the second direction to determine the sensor bias is further based on data from a third sensor of the at least two sensors.

10. The computer-readable medium of claim 9, wherein the third sensor is one of a magnetometer and an accelerometer.

11. The computer-readable medium of claim 8, wherein the first sensor is a gyroscopic sensor and wherein the second sensor is one of a magnetometer and an accelerometer.

12. The computer-readable medium of claim 8, wherein the filtering is performed with a Bayesian filter.

13. The computer-readable medium of claim 8, wherein the filtering of the set of sensor data the first time filters the data in a forward-in-time direction and the filtering of the set of sensor data the second time filters the data in a backward-in-time direction.

14. The computer-readable medium of claim 8, wherein the set of sensor data is received from a mobile device and wherein the method further comprises communicating the revised determined bias in response to the sensor bias converging.

15. A mobile device comprising:

a plurality of movement sensors, wherein the plurality of sensors comprises at least two movement sensors;

a processor configured to;

receive a set of sensor data, wherein the set of sensor data comprises data from at least two movement sensors of a device and wherein the sensor data corresponds to a movement of the device, and wherein the movement sensors include at least one of a gyroscope, a magnetometer, and an accelerometer;

communicate at least a subset of the set of sensor data to a remote server;

determine a sensor bias for a first sensor of the at least two movement sensors by iteratively;

filtering data from a first sensor of the two movement sensors a first time to determine the sensor bias based on data from a second sensor of the at least two movement sensors, and wherein the filtering of the data the first time filters the data in one of a forward-in-time direction or a backward-in-time direction;

adjusting the set of sensor data based on the determined bias;

filtering the data from the first sensor a second time to revise the determined sensor bias, wherein the filtering is performed based on the data from the second sensor of the at least two movement sensors, and wherein the filtering of the data the second time filters the data in the other one of the forward-in-time direction or the backward-in-time direction;

adjusting the set of sensor data based on the revised determined bias; and

supplementing the adjusted sensor data based on calculations performed by the server;

a memory configured to store the adjusted sensor data in a memory.

16. The mobile device of claim 15, wherein:

the filtering of the set of sensor data in the first direction to determine the sensor bias is further based on data from a third sensor of the plurality of movement sensors; and

the filtering of the set of sensor data in the second direction to determine the sensor bias is further based on data from a third sensor of the plurality of movement sensors.

17. The mobile device of claim 16, wherein the third sensor is one of a magnetometer and an accelerometer.

18. The mobile device of claim 15, wherein the first sensor is a gyroscopic sensor and wherein the second sensor is one of a magnetometer and an accelerometer.

19. The mobile device of claim 15, wherein the filtering is performed with a Bayesian filter.

20. The mobile device of claim 15, wherein the filtering of the set of sensor data the first time filters the data in a forward-in-time direction and the filtering of the set of sensor data the second time filters the data in a backward-in-time direction.