System for sensing road and traffic conditions

• US 8,423,255 B2
• Filed: 06/26/2008
• Issued: 04/16/2013
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Padmanabhan, Venkata N., Ramjee, Ramachandran, Mohan, Prashanth
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): ALHARBI, ADAM MOHAMED
• Application Number:
  US12/147,438
• Publication Number:
  US 20090192688A1
• Time in Patent Office: 1,755 Days
• Field of Search: 701/1, 701/29, 701/35, 701 45- 49, 701/70, 701/117, 701/200, 701/213, 701/220, 340/901, 340/905, 340/933, 340934-936
• US Class Current: 701/70
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions

Abstract

A traffic sensing system for collecting information on traffic conditions is provided. A traffic sensing system includes a traffic sensing server and a mobile traffic sensing device that sends traffic reports to the traffic sensing server. An MTS device may use an accelerometer integrated into a smart phone to detect potholes, to detect when the vehicle is braking, to detect whether the MTS device is being transported via a vehicle or a pedestrian, to detect horns sounding, and so on. The MTS device reports the various conditions to the traffic sensing server for accurate assessment of traffic conditions at stretches of road through which vehicles transporting MTS devices travel.

Claims

1. A traffic sensing system for collecting information on traffic conditions, the system comprising:

a traffic sensing server for receiving traffic reports from mobile traffic sensing devices and providing aggregate traffic reports from the received traffic reports; and

a plurality of mobile traffic sensing devices for sensing traffic-related information near the devices and sending traffic reports to the traffic sensing server, the mobile traffic sensing devices being smart phones being transported by vehicles, each smart phone being arbitrarily oriented in a vehicle, each smart phone including an accelerometer and a cellular communication device, a component that determines the orientation of the accelerometer based on a direction of travel of the vehicle transporting the smart phone as indicated by a braking force of the vehicle and based on a direction of gravity as indicated by a gravitational force, the orientation being determined even though the accelerometer is included in a smart phone that is arbitrarily oriented in the vehicle, a component that samples the accelerometer, and a component that derives traffic-related information from the accelerometer samples.

2. The traffic sensing system of claim 1 wherein the component that determines the orientation computes a pre-rotation angle, a tilt angle, and a post-rotation angle based on the gravitational and braking forces.

3. The traffic sensing system of claim 2 wherein the accelerometer is virtually re-oriented so that to a canonical direction of X is along the forward direction of a vehicle transporting a mobile traffic sensing device, Y is along the direction to the side of the vehicle, and Z is vertically down.

4. The traffic sensing system of claim 1 wherein the braking forces are generated as a result of movement of a vehicle transporting a mobile traffic sensing device.

5. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a component that detects whether a vehicle that is transporting the device is currently braking.

6. The traffic sensing system of claim 5 wherein a mobile traffic sensing device detects whether the vehicle that is transporting the mobile traffic sensing device is braking based on changes in accelerometer reading.

7. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a microphone for sampling ambient sound near the device and a component that detects whether a horn is sounding based on the sampling of the ambient sound.

8. The traffic sensing system of claim 7 wherein the component that detects whether a horn is sounding does so based on generating a frequency spectrum of the samples of ambient sound and detecting multiple peaks with one peak being within a characteristic frequency associated with a sounding horn.

9. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a component that detects whether a vehicle transporting the device has encountered a pothole.

10. The traffic sensing system of claim 9 wherein the component that detects whether a vehicle has encountered a pothole does so by checking for a spike in accelerometer samples in a vertical direction when the vehicle is traveling faster than a slow speed threshold and by checking for a sustained dip in the accelerometer samples when the vehicle is traveling slower than the slow speed threshold.

11. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a component that detects whether the device is being transported by a vehicle or a pedestrian.

12. The traffic sensing system of claim 11 wherein the component that detects whether the device is being transported by a vehicle or a pedestrian does so by determining whether braking is detected based on changes in accelerometer samples.

13. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a component that determines location of the device based on signals received by the device from cellular transmitters and an intersection of convex hulls that represent transmission range of those cellular transmitters.

14. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a microphone for sampling ambient sound near the device and a component that detects enclosure type of a vehicle transporting the device based on a level of the ambient sound.

15. The traffic sensing system of claim 14 wherein some mobile traffic sensing devices send traffic reports to other mobile traffic sensing devices via a local area wireless network and wherein the enclosure type is based in part on traffic reports received from other mobile traffic sensing devices.

16. The traffic sensing system of claim 1 wherein some mobile traffic sensing devices send traffic reports to other mobile traffic sensing devices via a personal-area wireless network and include a component that detects whether a device is currently being transported by a mass transit vehicle based on proximity to the other devices as indicated by the traffic reports.

17. The traffic sensing system of claim 1 wherein a mobile traffic sensing device includes a higher energy consumption device that is enabled only when an algorithm that uses data of a lower energy consumption device determines that data from the higher energy consumption device is needed.

18. A traffic sensing system for collecting information on traffic conditions, the system comprising:

a traffic sensing server that receives traffic reports from mobile traffic sensing devices and provides aggregate traffic reports generated from the received traffic reports; and

a plurality of mobile traffic sensing devices that each includes;

a cellular phone with a microphone;

a global positioning system device;

an accelerometer; and

a component that generates and sends traffic reports while the mobile traffic sensing device is being transported via a vehicle, the mobile traffic sensing device having an arbitrary orientation within the vehicle, the component including;

a component that determines a current orientation of the accelerometer of the mobile traffic sensing device that has an arbitrary orientation in the vehicle, a component that samples the accelerometer and the global positioning system device,

a component that derives traffic-related information from the accelerometer based on the current orientation and the global positioning device samples, and

a component that samples the microphone as an indicator of ambient noise around the vehicle.

19. A cellular phone for collecting information on traffic conditions, the cellular phone comprising:

a microphone;

a global positioning system device;

an accelerometer;

a personal-area wireless network interface;

a memory storing computer-executable instructions of a component that generates and sends traffic reports while the cellular phone is being transported in a vehicle by determining orientation the accelerometer, sampling the accelerometer, the global positioning system device, and the microphone, inputting traffic reports via the personal-area wireless network interface from neighboring cellular phones that collect information about traffic conditions, and deriving traffic-related information from the accelerometer, the global positioning system device, and the microphone samples and the traffic reports input from neighboring cellular phones; and

a processor executing the instructions stored in the memory.