Altitude estimation using a probability density function

• US 9,918,294 B2
• Filed: 09/22/2016
• Issued: 03/13/2018
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Marti, Lukas M., MacGougan, Glenn Donald, Mayor, Robert, Huang, Ronald K., Dere, Jason, Grosman, Yefim
• Primary Examiner(s): TAYLOR, NATHAN SCOTT
• Application Number:
  US15/273,632
• Publication Number:
  US 20170013589A1
• Time in Patent Office: 537 Days
• Field of Search: 4554561-4563, 34235743
• CPC Class Codes: G01C 5/00 Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels G01C3/20, G01C3/30 take precedence
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

Methods, program products, and systems of location estimation using a probability density function are disclosed. In general, in one aspect, a server can estimate an effective altitude of a wireless access gateway using harvested data. The server can harvest location data from multiple mobile devices. The harvested data can include a location of each mobile device and an identifier of a wireless access gateway that is located within a communication range of the mobile device. The server can calculate an effective altitude of the wireless access gateway using a probability density function of the harvested data. The probability density function can be a sufficient statistic of the received set of location coordinates for calculating an effective altitude of the wireless access gateway. The server can send the effective altitude of the wireless access gateway to other mobile devices for estimating altitudes of the other mobile devices.

Claims

1. A method, comprising:

receiving, by one or more computers, data from one or more sampling devices;

determining, by the one or more computers, geographic coordinates and identifiers of wireless access gateways from the received data;

identifying, by the one or more computers, one or more wireless access gateways that have moved, wherein identifying the one or more wireless access gateway that have moved comprises;

identifying, for each wireless access gateway, a minimum latitude, a maximum latitude, a minimum longitude, and a maximum longitude of the wireless access gateway as represented in the data, and

determining, for each wireless access gateway, whether the wireless access gateway has moved based on the minimum latitude of the wireless, the maximum latitude of the wireless access gateway, the minimum longitude of the wireless access gateway, and the maximum longitude;

removing, by the one or more computers, data of the one or more moved wireless access gateways;

estimating, by the one or more computers, locations of the wireless access gateways that have not moved using the received data; and

transmitting the estimated locations of the wireless access gateways that have not moved to one or more requesting devices.

2. The method of claim 1, wherein

the identifying and the removing are performed by a daemon process in response to receiving the data from the one or more sampling devices;

and

the estimating is performed periodically or in response to a request and is performed independently from the identifying and removing.

3. The method of claim 1, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining a difference between altitudes of a wireless access gateway as represented in the data; and

determining the wireless access gateway has moved in response to determining the difference is greater than a threshold.

4. The method of claim 1, wherein determining whether the wireless access gateway has moved further comprises:

determining a first difference between the maximum longitude and the minimum longitude of the wireless access gateway;

determining a second difference between the maximum latitude and the minimum latitude of the wireless access gateway; and

determining whether the wireless access gateway has moved based on the first difference and the second difference.

5. The method of claim 4, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining the wireless access gateway has moved in response to determining that a weighted combination of the first difference and the second difference is greater than a threshold.

6. At least one non-transitory storage medium storing computer instructions configured to cause one or more computers to perform operations comprising:

receiving, by one or more computers, data from one or more sampling devices;

determining, by the one or more computers, geographic coordinates and identifiers of wireless access gateways from the received data;

identifying, by the one or more computers, one or more wireless access gateways that have moved, wherein identifying the one or more wireless access gateway that have moved comprises;

identifying, for each wireless access gateway, a minimum latitude, a maximum latitude, a minimum longitude, and a maximum longitude of the wireless access gateway as represented in the data, and

determining, for each wireless access gateway, whether the wireless access gateway has moved based on the minimum latitude of the wireless, the maximum latitude of the wireless access gateway, the minimum longitude of the wireless access gateway, and the maximum longitude;

removing, by the one or more computers, data of the one or more moved wireless access gateways;

estimating, by the one or more computers, locations of the wireless access gateways that have not moved using the received data; and

transmitting the estimated locations of the wireless access gateways that have not moved to one or more requesting devices.

7. The non-transitory storage medium of claim 6, wherein

the identifying and the removing are performed by a daemon process in response to receiving the data from the one or more sampling devices;

and

the estimating is performed periodically or in response to a request and is performed independently from the identifying and removing.

8. The non-transitory storage medium of claim 6, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining a difference between altitudes of a wireless access gateway as represented in the data; and

determining the wireless access gateway has moved in response to determining the difference is greater than a threshold.

9. The non-transitory storage medium of claim 6, wherein determining whether the wireless access gateway has moved further comprises:

determining a first difference between the maximum longitude and the minimum longitude of the wireless access gateway;

determining a second difference between the maximum latitude and the minimum latitude of the wireless access gateway; and

determining whether the wireless access gateway has moved based on the first difference and the second difference.

10. The non-transitory storage medium of claim 9, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining the wireless access gateway has moved in response to determining that a weighted combination of the first difference and the second difference is greater than a threshold.

11. A system comprising:

one or more computers; and

at least one non-transitory medium storing computer instructions configured to cause the one or more computers to perform operations comprising;

receiving, by the one or more computers, data from one or more sampling devices;

determining, by the one or more computers, geographic coordinates and identifiers of wireless access gateways from the received data;

identifying, by the one or more computers, one or more wireless access gateways that have moved, wherein identifying the one or more wireless access gateway that have moved comprises;

identifying, for each wireless access gateway, a minimum latitude, a maximum latitude, a minimum longitude, and a maximum longitude of the wireless access gateway as represented in the data, and

determining, for each wireless access gateway, whether the wireless access gateway has moved based on the minimum latitude of the wireless, the maximum latitude of the wireless access gateway, the minimum longitude of the wireless access gateway, and the maximum longitude;

removing, by the one or more computers, data of the one or more moved wireless access gateways;

estimating, by the one or more computers, locations of the wireless access gateways that have not moved using the received data; and

transmitting the estimated locations of the wireless access gateways that have not moved to one or more requesting devices.

12. The system of claim 11, wherein

the identifying and the removing are performed by a daemon process in response to receiving the data from the one or more sampling devices;

and

the estimating is performed periodically or in response to a request and is performed independently from the identifying and removing.

13. The system of claim 11, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining a difference between altitudes of a wireless access gateway as represented in the data; and

determining the wireless access gateway has moved in response to determining the difference is greater than a threshold.

14. The system of claim 11, wherein determining whether the wireless access gateway has moved further comprises:

determining a first difference between the maximum longitude and the minimum longitude of the wireless access gateway;

determining a second difference between the maximum latitude and the minimum latitude of the wireless access gateway; and

determining whether the wireless access gateway has moved based on the first difference and the second difference.

15. The system of claim 14, wherein identifying the one or more wireless access gateway that have moved further comprises:

determining the wireless access gateway has moved in response to determining that a weighted combination of the first difference and the second difference is greater than a threshold.