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

• US 7,647,171 B2
• Filed: 06/29/2005
• Issued: 01/12/2010
• Est. Priority Date: 06/29/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Krumm, John C., Horvitz, Eric I.
• Primary Examiner(s): Tran; Dalena
• Application Number:
  US11/171,891
• Publication Number:
  US 20070005243A1
• Time in Patent Office: 1,658 Days
• Field of Search: 701/213, 701/201, 701/208, 701/211, 701/212, 340/995.1, 340/990, 348/14.07, 348/42, 345418-422, 345/426
• 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 receives and processes location information from a plurality of wireless receiving devices that generate the location information based at least in part on GPS signals, the location information received from each wireless receiving device of the plurality of wireless receiving devices indicating locations of the wireless receiving device upon entering and exiting an area of interruption or total blockage of the GPS signals; and

an analysis component that generates a shadow map of a communications shadow based on the location information, the shadow map representing areas of interruption or total blockage of the GPS signals, and the analysis component comprising at least one processor.

2. The system of claim 1, wherein:

the processing component utilizes the location information, which is geographic location information, and the shadow map to compute velocity information at which a device of the plurality of wireless devices enters a shadow; and

the velocity information is employed for reasoning about activities and context of a user of the device.

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

4. The system of claim 3, wherein the plurality of wireless receiving devices comprise cellular telephones.

5. The system of claim 1, wherein the processing component receives device health data from the wireless receiving devices 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 of a device with a GPS receiver desires to be automatically performed.

7. The system of claim 1, wherein the at least one processor comprises a processor of a server coupled to the plurality of wireless receiving devices over an IP network.

8. The system of claim 1, wherein the location information is geographic coordinates that define locations of the plurality of wireless receiving devices, and which location information changes as the wireless receiving across a boundary of the communications shadow.

9. The system of claim 1, further comprising a shadow map data store that provides access to a plurality of generated shadow maps to the plurality of wireless receiving devices.

10. A method of operating a computing system to generating a data store of shadow maps for determining context of wireless communications devices, the method comprising:

with at least one processor;

receiving device location data from a plurality of wireless communications devices that move in relation to a GPS shadow, the GPS shadow representing areas of interruption or total blockage of GPS signals, and the device location data from each wireless communications device indicating locations of the wireless communications device upon entering and exiting the GPS shadow;

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

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

storing the map in a data store;

relating an organization to a location within the GPS shadow;

inferring that a wireless communication device of the plurality of wireless communication devices has entered the organization based on a loss of GPS signal near the location; and

inferring an activity of a user of the wireless communication device based on a type of the organization related to the location.

11. The method of claim 10, wherein:

the device location data includes device health data that indicates a status of the wireless communications devices; and

analyzing the device location data comprises excluding from the analysis device location data from one or more wireless communication devices for which the device health data does not indicate correct operation.

12. The method of claim 10, further comprising an act of storing the map in association with a GPS shadow-producing structure.

13. The method of claim 10, further comprising an act of processing the device location data and other data to determined speed and direction of the wireless communications device.

14. The method of claim 10, further comprising an act of inferring features of the GPS shadow based on device location data received, processed, and analyzed from a plurality of wireless communications devices, and other data accessed from other data sources.

15. The method of claim 10, 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.

16. The method of claim 10, 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.

17. The method of claim 10, further comprising an act of mapping of the GPS shadow incrementally over time to generate a plurality of maps of the GPS shadow applicable at different times based on relative motion of the earth and one or more GPS satellites.

18. The method of claim 17, further comprising an act of combining the plurality of maps to define overall dimensions of the GPS shadow.

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

a server comprising at least one processor implementing;

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, the GPS shadow representing areas of interruption or total blockage of GPS signals;

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.

20. The system of claim 19, further comprising:

means for disabling a GPS receiver on a wireless communication device of the plurality of wireless communication devices upon entering the GPS shadow and re-enabling the GPS receiver on the wireless communication device in response to a measured acceleration of the wireless communication device that exceeds a threshold.