System for using cellular phones as traffic probes

• US 7,650,227 B2
• Filed: 03/17/2005
• Issued: 01/19/2010
• Est. Priority Date: 03/17/2004
• Status: Expired due to Fees

• Current Assignee: Globis Data, Inc.
• Original Assignee: Globis Data, Inc.
• Inventors: Kirk, Barrie, Fagan, Keith
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US10/598,625
• Publication Number:
  US 20070189181A1
• Time in Patent Office: 1,769 Days
• Field of Search: 701117-119, 701/207, 701/213, 701/214, 701/216, 370/252, 370/260, 370/349, 455/456.1, 455/403, 340/995.13, 340/995.27, 340/905, 340/992
• US Class Current: 701/117
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• 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: H04L 43/106 using time related information in packets, e.g. by adding timestamps
• CPC Class Codes: H04L 43/12 Network monitoring probes
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 67/52 specially adapted for the location of the user terminal

Abstract

A system and method for determining the flow of traffic in a monitored route segment using global positioning system, or assisted global positioning system, enabled cellular phones as traffic probes takes advantage of the existing cellular infrastructure to deploy traffic probes to determine the flow of traffic based on the speed and direction of probes. Filtering of probe data can be used to remove probes having outlying results such as excessive speed, or probes that do not fit the general trend already observed on a traffic route segment.

Claims

1. A method of determining the flow of traffic on a monitored route segment comprising:

obtaining and storing location information for a plurality of assisted global positioning system enabled cellular traffic probes;

determining the speed of each of the plurality of cellular traffic probes based only on the stored location including determining a distance traveled by each probe having a database entry with a most recent timestamp since a previous timestamp, and dividing the determined distance by the time between timestamps;

selecting a subset of the plurality of cellular traffic probes corresponding to probes having a location in the monitored route segment; and

determining the traffic flow for the monitored route segment on the basis of the determined speed of the probes in the selected subset.

2. The method of claim 1 wherein the step of determining the speed includes determining the speed of each of the plurality of probes based on the stored location and historical data.

3. The method of claim 1 wherein the step of obtaining includes requesting location information from a location based service platform.

4. The method of claim 3 wherein requesting location information includes transmitting a request over a virtual private network to a cellular carrier location based service platform.

5. The method of claim 1 wherein the step of storing the location information includes storing a probe identifier, a timestamp and a probe location in a database.

6. The method of claim 1 wherein the step of determining the speed includes obtaining a velocity vector from the location information.

7. The method claim 1 wherein the step of determining the speed includes determining a direction of travel for each probe having a database entry.

8. The method of claim 7 wherein the step of determining a direction includes comparing a most recently stored location to a previously stored location.

9. The method of claim 7 wherein the step of selecting a subset includes selecting all probe locations in a defined area having a defined determined direction of travel.

10. The method of claim 1 wherein the step of selecting a subset includes selecting all probe locations in a defined area.

11. The method of claim 1 wherein the step of determining the traffic flow includes grading the traffic flow in accordance with the speed of the selected subset of probes.

12. The method of claim 1 further including the step of filtering the selected subset to remove outlying probe values prior to the step of determining the traffic flow.

13. The method of claim 12 wherein the step of filtering includes determining a distribution of the probes in the subset, and removing from the subset any probe having speed more than two standard deviations from the normal of the distribution.

14. The method of claim 12 wherein the step of filtering includes determining an average speed of the probes in the subset, and removing from the subset any probe having a speed more than a predetermined amount away from the determined average speed.

15. A system for monitoring and determining the flow of traffic on a monitored route segment, the system comprising:

a location fetcher for obtaining and storing location information for a plurality of assisted global positioning system enabled cellular traffic probes;

a location processor for determining the speed of each of the plurality of cellular traffic probes based only on the stored location information by determining a distance traveled by each probe having a database entry with a most recent timestamp since a previous timestamp, and dividing the determined distance by the time between timestamps; and

a mapping engine for selecting a subset of the plurality of cellular traffic probes corresponding to probes having a location in the monitored route segment and for determining a traffic flow rating on the basis of the determined speed of the probes in the selected subset.

16. The system of claim 15 wherein the location information includes position and velocity vectors.

17. The system of claim 15 wherein the location fetcher includes a location based service platform interface for connecting to a location based service platform to request and receive location information for the plurality of assisted global positioning system enabled cellular traffic probes.

18. The system of claim 15 wherein the mapping engine includes a filter for selecting a subset of the plurality of probes corresponding to probes having a location in the monitored route segment, a speed within a ranged determined in accordance with the speed of other probes in the subset, and a predetermined direction.