Dead reconing system based on locally measured movement

• US 9,602,974 B2
• Filed: 05/02/2014
• Issued: 03/21/2017
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Trimble Inc.
• Original Assignee: Trimble Inc.
• Inventors: Wold, Robert, Rudow, Richard, Kasirajan, Venkateswaran, Talbot, Nicholas C., Loomis, Peter Van Wyck, Weisenburger, Shawn D., Janky, James M.
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US14/268,993
• Publication Number:
  US 20140378170A1
• Time in Patent Office: 1,054 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
• CPC Class Codes: G01S 19/485 whereby the further system is an optical system or imaging system
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• 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 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A Global Navigation Satellite System (GNSS) chipset embedded within the cellular device is accessed. The GNSS chipset calculates raw pseudoranges. The raw pseudoranges are extracted from the GNSS chipset for processing elsewhere in the cellular device outside of the GNSS chipset. A position fix is calculated based on the raw pseudoranges. At a first point in time, a first image, and at a second point in time, a second image are obtained with an image capturing device that is in a known physical relationship with the cellular device. An estimate of a distance that the cellular device moved from the first point in time to the second point in time is calculated by processing image data collected from the first point in time to the second point in time. The position fix is processed based on the estimate of the distance.

Claims

1. A method of improving position determination of a cellular device using locally measured movement, the method comprising:

accessing a Global Navigation Satellite System (GNSS) chipset embedded within the cellular device, wherein the GNSS chipset calculates raw pseudoranges;

extracting the raw pseudoranges from the GNSS chipset for processing elsewhere in the cellular device outside of the GNSS chipset;

calculating a position fix based on the raw pseudoranges;

obtaining, at a first point in time, a first image with an image capturing device that is in a known physical relationship with the cellular device;

obtaining, at a second point in time, a second image with the image capturing device;

calculating an estimate of a distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for a time frame from the first point in time to the second point in time; and

processing the position fix based on the estimate of the distance,

wherein the accessing, the extracting, the calculating of the position fix, the obtaining the first image, the obtaining the second image, the calculating of the estimate, and the processing of the position fix are performed by one or more hardware processors located in the cellular device and outside of the GNSS chipset.

2. The method as recited by claim 1, wherein the estimate is a first estimate and wherein the method further comprises:

obtaining, at the first point in time, first accelerometer data from an accelerometer that is part of the cellular device;

obtaining, at the second point in time, second accelerometer data from the accelerometer;

calculating a second estimate of the distance based on the first accelerometer data and the second accelerometer data; and

determining a third estimate by blending the first estimate and the second estimate using a filter,

wherein the obtaining of the first accelerometer data, the obtaining of the second accelerometer data, the calculating of the second estimate and the determining of the third estimate are performed by the one or more hardware processors.

3. The method as recited by claim 1, wherein the processing of the position fix further comprises:

determining whether to discard the position fix based on the estimate of the distance; and

if the position fix is discarded,

interpolating a new position fix based on the distance and two or more position fixes that precede the discarded position fix; and

replacing the discarded position fix with the new position fix,

wherein the determining whether to discard, the interpolating and the replacing are performed by the one or more hardware processors.

4. The method as recited by claim 3, wherein the raw pseudoranges are current raw pseudoranges, wherein the position fix is a current position fix at the second point in time, and wherein the method further comprises:

extracting previous raw pseudoranges from the GNSS chipset, wherein the previous raw pseudoranges are extracted before the current raw pseudoranges are extracted;

determining a previous position fix, for the first point in time, based on the previous raw pseudoranges;

determining a position fix distance that is a difference between the current position fix and the previous position fix;

determining a second difference between the estimate of the distance and the position fix distance; and

if the second difference exceeds a metric threshold, discarding the current position fix,

wherein the extracting of the previous raw pseudoranges, the determining of the previous position fix, the determining of the position fix distance, the determining of the second difference and the discarding of the current position fix are performed by the one or more hardware processors.

5. The method as recited by claim 4, wherein the position fix is a current position fix of the cellular device and wherein the interpolating of the new position fix further comprises:

determining a trajectory of movement of the cellular device based on two or more position fixes, which are previous to the current position fix, of the cellular device; and

interpolating the new position fix based on the estimate of the distance and the trajectory.

6. The method as recited by claim 1, wherein the calculating of the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time further comprises:

replacing a set of image data related to at least five key-points included in the first image with a set of image data related to at least five same key-points included in the second image.

7. The method as recited by claim 1, wherein the obtaining, at the first point in time, of the first image with the image capturing device further comprises:

calibrating the image capturing device to correct the image for lens distortion, the lens distortion selected from a group consisting of a principal distance distortion, a focal length, a principal point offset, a radial distortion, and a tangential distortion.

8. The method as recited by claim 1, wherein the calculating the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time further comprises:

calculating the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time using a sequential rolling bundle adjustment algorithm.

9. The method as recited by claim 1, wherein the position fix is a current position fix of the cellular device and wherein the method further comprises:

obtaining a set of images 1 to n using the image capturing device from at least the first point in time to the second point in time, each image of the set of images 1 to n includes a set of image data and images 1 to n−

1 has at least one respective subsequent image and images 2 to n has at least one respective previous image;

calculating position fix estimates of positions of the cellular device between the first point in time and the second point in time by replacing a set of image data included in an image with a set of image data included in a respective subsequent image;

determining a previous position fix, based on previous raw pseudoranges, wherein the previous position fix correlates with a position of the cellular device at a time that is less than or equal to the second point in time; and

determining the estimate of the distance based on the previous position fix and at least one of the position fix estimates.

10. A system for improving position determination of a cellular device using locally measured movement, the system comprising:

accessing logic that accesses a Global Navigation Satellite System (GNSS) chipset embedded within the cellular device, wherein the GNSS chipset calculates raw pseudoranges;

extracting logic that extracts the raw pseudoranges from the GNSS chipset for processing elsewhere in the cellular device outside of the GNSS chipset;

position fix determining logic that calculates a position fix based on the raw pseudoranges;

image capturing device movement information accessing logic that obtains, at a first point in time, a first image with an image capturing device that is in a known physical relationship with the cellular device and that obtains, at a second point in time, a second image with the image capturing device; and

processing logic that calculates an estimate of a distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for a time frame from the first point in time to the second point in time, and that processes the position fix based on the estimate of the distance,

wherein the accessing logic, the extracting logic, the image capturing device movement information accessing logic and the processing logic are performed by one or more hardware processors located in the cellular device and outside of the GNSS chipset.

11. The system of claim 10, wherein the image capturing device is selected from a group consisting of:

a digital camera, a digital video camera, a digital camcorder, a stereo digital camera, a stereo video camera, a motion picture camera, and a television camera.

12. The system as recited by claim 10, wherein the processing logic further comprises logic that:

determines whether to discard the position fix based on the estimate of the distance; and

if the position fix is discarded,

interpolates a new position fix based on the distance and two or more position fixes that precede the discarded position fix; and

replaces the discarded position fix with the new position fix.

13. The system as recited by claim 12, wherein the raw pseudoranges are current raw pseudoranges, wherein the position fix is a current position fix at the second point in time, and wherein:

the extracting logic further comprises logic that extracts previous raw pseudoranges from the GNSS chipset, wherein the previous raw pseudoranges are extracted before the current raw pseudoranges are extracted;

the position fix determining logic further comprises logic that determines a previous position fix, for the first point in time, based on the previous raw pseudoranges; and

the processing logic further comprises logic that determines a position fix distance that is a difference between the current position fix and the previous position fix and determines a difference between the estimate of the distance and the position fix distance, and if the difference exceeds a metric threshold, discards the current position fix.

14. The system as recited by claim 13, wherein the position fix is a current position fix of the cellular device and wherein the processing logic further comprises logic that:

determines a trajectory of movement of the cellular device based on two or more position fixes, which are previous to the current position fix, of the cellular device; and

interpolates the new position fix based on the estimate of the distance and the trajectory.

15. The system as recited by claim 10, wherein the processing logic further comprises logic that:

replaces a set of image data related to at least five key-points included in the first image with a set of image data related to at least five same key-points included in the second image as a part of calculating the estimate of the distance.

16. The system as recited by claim 10, wherein image capturing device movement information accessing logic further comprises logic that:

calibrates the image capturing device to correct the image for lens distortion, the lens distortion selected from a group consisting of a principal distance distortion, a focal length, a principal point offset, a radial distortion, and a tangential distortion.

17. The system as recited by claim 10, wherein the processing logic further comprises logic that:

calculates the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time using a sequential rolling bundle adjustment algorithm.

18. The system as recited by claim 10, wherein the cellular device comprises a cellular communication enabled mobile communications device.

19. A non-transitory computer readable storage medium having computer readable instructions stored thereon for causing a computer system to perform a method of improving position determination of a cellular device using locally measured movement, the method comprising:

accessing a Global Navigation Satellite System (GNSS) chipset embedded within the cellular device, wherein the GNSS chipset calculates raw pseudoranges;

extracting the raw pseudoranges from the GNSS chipset for processing elsewhere in the cellular device outside of the GNSS chipset;

calculating a position fix based on the raw pseudoranges;

obtaining, at a first point in time, a first image with an image capturing device that is in a known physical relationship with the cellular device;

obtaining, at a second point in time, a second image with the image capturing device;

calculating an estimate of a distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for a time frame from the first point in time to the second point in time; and

processing the position fix based on the estimate of the distance,

wherein the accessing, the extracting, the calculating of the position fix, the obtaining the first image, the obtaining the second image, the calculating of the estimate, and the processing of the position fix are performed by one or more hardware processors located in the cellular device and outside of the GNSS chipset.

20. The non-transitory computer readable storage medium as recited by claim 19, wherein the calculating the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time further comprises:

calculating the estimate of the distance that the cellular device moved from the first point in time to the second point in time by processing image data collected for the time frame from the first point in time to the second point in time using a sequential rolling bundle adjustment algorithm.

21. The non-transitory computer readable storage medium as recited by claim 19, wherein the processing of the position fix further comprises:

determining whether to discard the position fix based on the estimate of the distance; and

if the position fix is discarded,

interpolating a new position fix based on the distance and two or more position fixes that precede the discarded position fix; and

replacing the discarded position fix with the new position fix,

wherein the determining whether to discard, the interpolating and the replacing are performed by the one or more hardware processors.

22. The non-transitory computer readable storage medium as recited by claim 19, wherein the method further comprises:

collecting position fixes from the first point in time to the second point in time;

collecting synchronized video that includes a plurality of images from the first point in time to the second point time;

initializing an image processing algorithm;

locating correspondences;

performing sequential rolling bundle adjustment;

adding new locally measured movement information from new images, wherein the new images are taken with the cellular device; and

adding new position fixes based on the new measurements,

wherein the collecting of the position fixes, the collecting of synchronized video, the initializing of the image processing algorithm, the locating of correspondences, the performing of the sequential rolling bundle adjustment, the adding of new locally measured movement information and the adding of new position fixes are performed by the one or more hardware processors.