Telematics using personal mobile devices

• US 8,457,880 B1
• Filed: 11/28/2012
• Issued: 06/04/2013
• Est. Priority Date: 11/28/2012
• Status: Active Grant

• Current Assignee: Cambridge Mobile Telematics, Inc.
• Original Assignee: Cambridge Mobile Telematics, Inc.
• Inventors: Balakrishnan, Hari, Malalur, Paresh Govind, Madden, Samuel Ross
• Primary Examiner(s): Nguyen, Kim T
• Application Number:
  US13/687,479
• Time in Patent Office: 188 Days
• Field of Search: 701/408, 701/409, 701/410, 701/522, 701/541
• US Class Current: 701/410
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G06Q 40/08 Insurance
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An approach to telematics using mobile devices provides battery-efficient trajectory and mileage inference from inaccurate and intermittent location data. Accurate trajectories of how users or vehicles move in the physical world are formed by processing raw position estimates obtained from noisy, inaccurate, and error-prone position sensors on mobile devices, where the position data may also arrive intermittently with long time gaps. The trajectory is formed using the process of map matching, which determines the trajectory on a map that best explains the sequence of position observations.

Claims

1. A method for map-based telematics comprising:

acquiring data representing a sequence of position-related measurements O₁ . . . , O_t of a device traveling along segments s of a transportation network;

processing data representing the position measurements to form a sequence of segment sets S₀, . . . , S_D, each segment set being associated with a set of one or more position measurements in the sequence of position measurements; and

applying a computer-implemented path forming procedure to form a path set between the segment sets (S₀,S_D) including determining a plurality of subsequences of the sequence S₀, . . . , S_D and forming paths through the determined subsequences; and

providing data representation of a characteristic of the traversal of the device based on the formed path set.

2. The method of claim 1 wherein determining the plurality of subsequences comprises determining substantially all subsequences of the sequence S₁, . . . S_D−

1.

3. The method of claim 1 wherein applying a computer-implemented path forming procedure to form the path set representing a traversal of the transportation network between a pair of segment sets (S₀,S_D) further includes:

determining a path set between segments in segment set S_i and segments in segment set S_j,

applying the path forming procedure to form a first intermediate path set representing traversal of the network between an intermediate pair of segments (S_i′

,S_j′

), where i≦

i′

<

j′

≦

j; and

determining the path set at least in part according to the formed first intermediate path set.

4. The method of claim 3 wherein applying the path forming procedure for the pair of segments (S_i,S_j) further includes selecting a k^th segment set S_k that is intermediate to the i^th and j^th segment sets such that i<

k<

j, and wherein the first intermediate path set represents traversal between either segment sets (S_i,S_k) or (S_k,S_i).

5. The method of claim 4 wherein applying the path forming procedure for the pair of segments (S_i,S_j) further includes applying the path forming procedure to form a second intermediate path set representing traversal of the network over between an intermediate pair of segment sets (S_i,S_k) or (S_k,S_i), and wherein determining the path set is according to the formed first intermediate path set and the formed second intermediate path set.

6. The method of claim 1 wherein the path forming procedure applied to a pair of segment sets (S_a,S_b) forms a path set consisting of a single best path representing a path between a segment of S_a and a segment of S_b.

7. The method of claim 1 wherein the path forming procedure applied to a pair of segment sets (S_a,S_b) forms a path set comprising a plurality of best paths each best path representing a path between a pair of segments (s_a,s_b) in the corresponding pair of segment sets (S_a,S_b).

8. The method of claim 1 wherein at least one of the segment sets is associated with more than one of the position-related measurements.

9. The method of claim 8 further comprising grouping the position-related measurements, and forming each segment set according to a corresponding one of the groups of measurements.

10. The method of claim 1 wherein providing the data representation of the characteristic of the traversal of the device comprises providing data representing a path of the traversal of the device through the transportation network.

11. The method of claim 10 wherein determining a best path between a segment of S_i and a segment of S_j includes determining an overall score for the path by applying a precomputed map-based score for traversal of the network between pairs of segments of segment sets S_i and S_j.

12. The method of claim 11 determining a best path between a segment of S_i and a segment of S_j further includes applying measurement data acquired during travel of the device along the network in determining the overall score for the path.

13. The method of claim 12 wherein the measurement data comprises at least some of the position-related measurements.

14. The method of claim 12 wherein the method further comprises acquiring sensor measurement data at the device during the travel of the device, and the measurement data applied in determining the overall score for a path includes at least some of the sensor measurement data.

15. The method of claim 14 wherein the sensor measurement data comprises inertial measurement data.

16. The method of claim 14 wherein the sensor measurement data comprises acoustic measurement data.

17. The method of claim 1 wherein providing the data representation of the characteristic of the traversal of the device comprises providing data representing a distance of a path in the formed path set and a velocity characteristic of a traversal of a path in the formed path set.

18. The method of claim 1 wherein providing the data representation of the characteristic of the traversal of the device comprises providing driver risk data to an insurance provider.

19. The method of claim 1 wherein the path set between segments in segment set S_i and segments in segment set S_j consists of a single best path between a segment of S_i and a segment of S_j.

20. The method of claim 1 wherein the position-related measurements comprise positioning system measurements.

21. The method of claim 20 wherein the positioning system measurements comprise satellite positioning system measurements.

22. The method of claim 1 wherein the position-related measurements comprise measurements based on radio transmissions between the device and stationary transmitters.

23. The method of claim 22 wherein the radio transmissions between the device and stationary transmitters comprise cellular telephone transmissions between the device and cellular telephone base stations.

24. The method of claim 22 wherein the radio transmissions between the device and stationary transmitters comprise transmissions from known wireless local area network stations to the device.

25. The method of claim 24 further comprising selecting whether to cause the acquisition according to a cost of the acquisition.

26. The method of claim 25 wherein the cost of the acquisition comprises a power consumption cost.

27. The method of claim 1 further comprising causing acquisition of further position-related measurements according to a result of the path forming procedure.

28. The method of claim 1 wherein the device comprises a personal communication device.

29. The method of claim 28 wherein the personal communication device travels within a vehicle along a road transportation network.

30. Software stored on a non-transitory computer-readable medium comprising instructions for causing a data processing system to:

acquire data representing a sequence of position-related measurements O₁, . . . , O_t of a device traveling along segments s of a transportation network;

process data representing the position measurements to form a sequence of segment sets S₀, . . . , S_D, each segment set being associated with a set of one or more position measurements in the sequence of position measurements; and

apply a path forming procedure to form a path set between the segment sets (S₀,S_D) including determining a plurality of subsequences of the sequence S₀, . . . , S_D and forming paths through the determined subsequences; and

provide data representation of a characteristic of the traversal of the device based on the formed path set.