Learning, storing, analyzing, and reasoning about the loss of location-identifying signals

• US 20070005243A1
• Filed: 06/29/2005
• Published: 01/04/2007
• Est. Priority Date: 06/29/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Horvitz, Eric, Krumm, John
• Granted Patent: US 7,647,171 B2
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/39 the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO

Abstract

A location-centric signal shadow mapping and storing architecture that creates maps where signals, such as GPS, cannot be seen with ease because of natural or synthetic features such as groups of tall buildings. Such maps are used with other information, such as the dynamics of the sensed velocity that had been seen before the loss of the signals, to reason about the location and likely activities being carried out by one or more people. Inferences can be made based on information about organizations and services associated with structures and locations proximal to the locations where signals were lost. Also, such reasoning can be used to turn off or to reduce the power consumed by the receivers of the location information, potentially with the joint use of accelerometers to identify when significant accelerations occur.

Claims

1. A system that facilitates shadow mapping, comprising:

a processing component that processes location information received from a wireless receiving device; and

an analysis component that facilitates generation of a shadow map of a communications shadow based on the location information.

2. The system of claim 1, wherein the processing component utilizes the location information, which is geographic location information, to compute velocity information at which a device enters a shadow, which velocity information is employed for reasoning about activities and context.

3. The system of claim 1, wherein the wireless receiving device is a mobile communications device that utilizes wireless assisted GPS (WAGPS) to determine the location of an approximate border of the communications shadow.

4. The system of claim 3, wherein the wireless receiving device is a cellular telephone.

5. The system of claim 1, wherein the processing component receives device health data from the wireless receiving device and processes the device health data in combination with the location information to validate the location information.

6. The system of claim 1, further comprising a learning and reasoning component that employs a probabilistic and/or statistical-based analysis to prognose or infer a situation, goal, or an action that a user desires to be automatically performed.

7. A computer-readable medium having stored thereon computer-executable instructions for carrying out the system of claim 1.

8. A server that employs the system of claim 1.

9. The system of claim 1, wherein the location information is geographic coordinates that define a location of the wireless receiving device, and which location information changes as the wireless receiving device is moved across a boundary of the communications shadow.

10. The system of claim 1, further comprising a shadow map data store that provides access to a plurality of generated shadow maps.

11. A method of generating a data store of shadow maps, the method comprising:

receiving device data from a wireless communications device that is moved in relation to a GPS shadow;

analyzing the device data to determine features of the GPS shadow;

processing the features to generate a map of the GPS shadow; and

storing the map in a data store.

12. The method of claim 11, wherein the device data includes device health data that indicates a status of the wireless communications device and GPS location data that defines a location of the wireless communications device.

13. The method of claim 11, further comprising an act of storing the map in association with a GPS shadow-producing structure.

14. The method of claim 11, further comprising an act of processing the device data and other data to determined speed and direction of the wireless communications device.

15. The method of claim 11, further comprising an act of inferring features of the GPS shadow based on device data received, processed, and analyzed from a plurality of wireless communications devices, and other data accessed from other data sources.

16. The method of claim 11, further comprising an act of moving the wireless receiving device through an urban canyon of GPS shadow-producing structures to map GPS shadows associated with the structures.

17. The method of claim 11, wherein an act of receiving is via at least one of a cellular network and an IP network such that the map is stored on the data store which is on the IP network.

18. The method of claim 11, further comprising an act of mapping of the GPS shadow incrementally over time to generate a plurality of maps of the GPS shadow.

19. The method of claim 18, further comprising an act of combining the plurality of maps to define overall dimensions of the GPS shadow.

20. A system that generates a data store of shadow maps, comprising:

means for receiving device data from a plurality of wireless communications devices that indicates a presence or absence of GPS signals;

means for analyzing the presence or absence of the GPS signals to determine a location of a GPS shadow;

means for computing a dimension of the GPS shadow based on the presence or absence of the GPS signals;

means for generating a map of the GPS shadow in relation to a shadow-producing structure; and

means for storing the map in a data store.