METHOD OF CREATING A SPEED ESTIMATION

• US 20100318286A1
• Filed: 04/22/2009
• Published: 12/16/2010
• Est. Priority Date: 04/23/2008
• Status: Abandoned Application

• Current Assignee: TomTom International BV (TomTom NV)
• Original Assignee: TomTom International BV (TomTom NV)
• Inventors: Schafer, Ralf-Peter, Lorkowski, Stefan, Schuurbiers, Rob, Groenhuijzen, Lucien, Mieth, Peter
• Application Number:
  US12/735,635
• Publication Number:
  US 20100318286A1
• Time in Patent Office: Days
• US Class Current: 701/119
• CPC Class Codes: G01S 19/52 Determining velocity
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions
• CPC Class Codes: G08G 1/0112 from the vehicle, e.g. floating car data [FCD]
• CPC Class Codes: G08G 1/0116 from roadside infrastructure, e.g. beacons
• CPC Class Codes: G08G 1/012 from other sources than vehicle or roadside beacons, e.g. mobile networks
• CPC Class Codes: G08G 1/0129 for creating historical data or processing based on historical data
• CPC Class Codes: G08G 1/0133 for classifying traffic situation
• CPC Class Codes: G08G 1/0141 for traffic information dissemination
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination

Abstract

A method of creating a speed estimation representative of vehicle speed along one or more road segments. In at least one embodiment, the method includes obtaining at least reference speed data from a reference source of data and second speed data from a second source of data, wherein the second source is different from the reference and the speed data is indicative of vehicle speed along the or each road segment; using the reference speed data to verify the second speed data and modifying the second speed data according to the verification; and generating an estimation of vehicle speed for the or each road segment based upon the verified second speed data.

Claims

1. A method of creating a speed estimation representative of vehicle speed along one or more road segments, the method comprising:

obtaining at least reference speed data from a reference source of data and second speed data from a second source of data, the second source of data being different from the reference source of data and the speed data being indicative of vehicle speed along the one or more road segments;

using the reference speed data to verify the second speed data and modifying the second speed data according to the verification; and

generating an estimation of vehicle speed for the one or more road segments based upon at least the verified second speed data.

2. A method according to claim 1, further comprising:

initially generating at least one of the reference speed data and the second speed data from position data obtained, respectively, from the reference source and second data sources.

3. A method according to claim 1, wherein the verification includes weighting speed data with one or more weighting factors, determinable for a given source of speed data, by learning from earlier data.

4. A method according to claim 1, arranged to generate a road segment weighting factor based upon the outcome of previous verifications.

5. A method according to claim 3, the one or more weighting factors applied to given speed data is decayed with time.

6. A method according to claim 4, further comprising:

assigning a probability to the speed data from each of the data sources having been generated from a vehicle upon the same road segment and using the assigned probability to generate, or at least modify, the road segment weighting factor.

7. A method according to claim 1, further comprising:

calculating a distribution between speed data from the reference data source and the second data source, which may be a normal distribution.

8. A method according to claim 7, wherein the calculating includes calculating at least one of a mean and a variance of the normal distribution.

9. A method according to claim 1, further comprising:

determining a speed bias within the speed data generated from second data source and subsequently modifying the second speed data to take account of the bias.

10. A method according to claim 8, further comprising utilizing the variance to determine a level of noise within the speed data generated from the second data source, the determination being utilizable in generating the road segment weighting factor.

11. A method according to claim 1, further comprising:

reporting a delay for the one or more road segments upon the generated speed estimation falling below a threshold.

14. A machine readable medium containing instructions which, when loaded onto a machine,

cause the machine to perform the method of claim 1.

15. A method according to claim 2, wherein the verification includes weighting speed data with one or more weighting factors, determinable for a given source of speed data, by learning from earlier data.

16. A method according to claim 4, the one or more weighting factors applied to given speed data is decayed with time.

17. A method according to claim 5, further comprising:

assigning a probability to the speed data from each of the data sources having been generated from a vehicle upon the same road segment and using the assigned probability to generate, or at least modify, the road segment weighting factor.

18. A method according to claim 9, further comprising utilizing the variance to determine a level of noise within the speed data generated from the second data source, the determination being utilizable in generating the road segment weighting factor.

12. A road traffic network reporting system arranged to monitor speed data for one or more road segments, the road traffic network reporting system comprising:

a storage device; and

processing circuitry connected to the storage device, the storage device being arranged to store reference speed data generated from position data received from a reference source of position data and to store second speed data generated from position data received from a second source of position data, the processing circuitry being arranged to

process the reference and second speed data to verify the second speed data,

modify the second speed data according to the verification, and

generate a fused speed data by fusing the reference and second speed data to generate an estimation of vehicle speed for the one or more road segments.

13. A system according to claim 12, wherein the processing circuitry is arranged to generate a delay warning upon the speed estimation falling below a threshold.

19. A machine readable medium containing instructions which, when loaded onto a machine, cause the machine to function as the, or at least part of, the system of claim 12.