Handset agent calibration for timing based locating systems

• US 9,026,133 B2
• Filed: 11/28/2011
• Issued: 05/05/2015
• Est. Priority Date: 11/28/2011
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Fix, Jeremy, Martinez, Francisco, Meredith, Sheldon Kent
• Primary Examiner(s): Prez-Gutirrez, Rafael
• Assistant Examiner(s): VU, QUOC THAI NGOC
• Application Number:
  US13/305,276
• Publication Number:
  US 20130137465A1
• Time in Patent Office: 1,254 Days
• Field of Search: 455/404.2, 455/433, 455/440, 455/456.1, 455/457
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 64/003 locating network equipment
• CPC Class Codes: H04W 8/16 selectively restricting mobility data tracking

Abstract

The systems and methods disclosed herein can implement a handset agent calibration solution that uses the GPS receivers on mobile devices to determine a location of the mobile device to calibrate timing based locating systems. The handset agent can be installed on the mobile device and can upload to an internet server the coordinates captured by the GPS receiver along with the observed time differences. The observed time differences and the location of the mobile device can be used to solve for reference time differences to calibrate unsynchronized macrocells. The reference time difference can be used to solve for the location of other mobile devices if the observed time differences between that mobile device and the macrocells are known. The solution can include receiving measurement reports from many mobile devices to obtain averaged observed time differences at a reference location to achieve more accurate reference time differences.

Claims

1. A method, comprising:

receiving, by a system comprising a processor, measurement report data representing a location of a first mobile device and observed time differences for signals that were received by the first mobile device and sent from macrocell devices in range of the first mobile device, wherein the location represents the location of the first mobile device at a time corresponding to the observed time differences being determined and wherein an observed time difference of the observed time differences is a difference between a first time indicating when a signal of the signals was sent from a macrocell device and a second time determined based on when the signal was received at the first mobile device;

translating, by the system, the observed time differences that correspond to the location to a set of translated observed time differences that correspond to a reference location, wherein the reference location and the location are different from each other;

determining, by the system, reference time differences for the macrocell devices as a function of the reference location and the set of translated observed time differences;

receiving, by the system, second observed time differences of signals from a second mobile device, wherein the second mobile device is different from the first mobile device;

calibrating the second observed time differences of signals with the reference time differences to create calibrated second observed time differences of signals wherein the calibrating the second observed time differences further comprises subtracting the reference time differences from the second observed time differences of signals for the macrocell devices; and

determining, by the system, a second location of the second mobile device based on the calibrated second observed time differences of signals.

2. The method of claim 1, wherein the determining the reference time differences comprises determining the reference time differences using locations of the macrocell devices.

3. The method of claim 1, wherein the translating the observed time differences comprises generating virtual observed time differences for virtual signals sent from the macrocell devices to the reference location, wherein the virtual observed time differences represent time differences that would be observed if the virtual signals were received at the reference location.

4. The method of claim 1, wherein the receiving the measurement report data comprises receiving the measurement report data from the first mobile device via a network device configured for communication according to an internet protocol.

5. The method of claim 1, wherein the receiving the measurement report data representing the location of the first mobile device comprises receiving coordinates from an agent that executes on the first mobile device.

6. The method of claim 1, wherein the set of translated observed time differences is a first set of translated observed time differences, the receiving comprises receiving the measurement report data from a plurality of mobile devices and the translating comprises translating a plurality of observed time differences for the plurality of mobile devices to a second set of translated observed time differences that correspond to the reference location, and further comprising:

averaging, by the system, the second set of translated observed time differences; and

determining, by the system, a second set of reference time differences based on the averaging the second set of translated observed time differences and the reference location.

7. The method of claim 1, wherein the reference time differences for the macrocell device are synchronization variations for the macrocell devices.

8. A system, comprising:

a memory that stores executable instructions; and

a processor, coupled to the memory, to facilitate execution of the executable instructions to perform operations, comprising;

receiving a measurement report that represents observed time differences for signals sent to a first mobile device from macrocell devices in range of the first mobile device and represents a location of the first mobile device corresponding to when the signals were received by the first mobile device, wherein the observed time differences represent differences between first times indicating when the signals were sent from the macrocell devices and second times determined based on when the signals were received at the first mobile device;

translating the observed time differences that correspond to the location to a set of translated observed time differences that correspond to a reference location, wherein the reference location and the location are different locations;

determining reference time differences for the macrocell devices as a function of the reference location and the set of translated observed time differences;

receiving second observed time differences of signals from a second mobile device, wherein the second mobile device is different from the first mobile device;

calibrating the second observed time differences with the reference time difference to create calibrated second observed time differences, wherein the calibrating the second observed time differences further comprises subtracting the reference time differences from the second observed time differences of signals for the macrocell devices; and

locating the second mobile device based on the calibrated second observed time differences.

9. The system of claim 8, wherein the determining comprises generating the reference time differences based on locations of the macrocell devices.

10. The system of claim 8, wherein the set of translated observed time differences are virtual observed time differences for virtual signals sent from the macrocell devices to the reference location, wherein the virtual observed time differences represent time differences that would be observed if the virtual signals were received at the reference location.

11. The system of claim 8, wherein the receiving the measurement report that represents the location comprises receiving the location of the first mobile device from an agent of the first mobile device.

12. The system of claim 8, wherein the receiving the measurement report comprises collecting measurement reports from a plurality of mobile devices determined to be in range of the macrocell devices.

13. The system of claim 12, wherein the translating comprises translating a plurality of observed time differences from the plurality of mobile devices to a plurality of virtual observed time differences that correspond to the reference location, wherein the plurality of virtual observed time differences represent time differences that would be observed if the virtual signals were received at the reference location.

14. The system of claim 13, wherein the operations further comprise:

averaging the virtual observed time differences as input to determining a second set of reference time differences.

15. The system of claim 8, wherein the operations further comprise:

receiving a primary scrambling code that identifies a macrocell device of the macrocell devices that corresponds to an observed time difference of the observed time differences.

16. The system of claim 8, wherein the measurement report comprises an indication of a strength of a signal of the signals.

17. A tangible computer-readable device comprising computer-executable instructions that, in response to execution, cause a computing device comprising a processor to perform operations, comprising:

receiving a measurement report representing observed time differences for signals received at a first mobile device and sent from macrocell devices in range of the first mobile device and representing a location of the first mobile device where the observed time differences were obtained, wherein an observed time difference of the observed time differences is a difference between a first time indicating when a signal of the signals was sent from a macrocell device and a second time determined based on when the signal was received at the first mobile device;

translating the observed time differences to a set of translated observed time differences that correspond to the location that correspond to a reference location, wherein the reference location is different than the location;

determining reference time differences for the macrocell devices based on the reference location and the set of translated observed time differences;

receiving second observed time differences of signals from a second mobile device, wherein the second mobile device is different from the first mobile device;

calibrating the second observed time differences with the reference time differences to create calibrated second observed time differences, wherein the calibrating the second observed time differences further comprises subtracting the reference time differences from the second observed time differences of signals for the macrocell devices; and

locating the second mobile device based on the calibrated second observed time differences.

18. The tangible computer-readable device of claim 17, wherein the operations further comprise:

determining virtual time differences for the reference location and the macrocell devices, wherein the virtual time differences are a function of distances between the reference location and the macrocell devices; and

determining reference time deviations between reference time differences and the virtual time differences.

19. The tangible computer-readable device of claim 18, wherein the operations further comprise:

calibrating the second observed time differences based on the reference time deviations.