METHOD AND APPARATUS FOR GEOLOCATING A WIRELESS COMMUNICATION UNIT

• US 20130210450A1
• Filed: 02/09/2012
• Published: 08/15/2013
• Est. Priority Date: 02/09/2012
• Status: Active Grant

• Current Assignee: Viavi Solutions UK Limted (Lumentum Holdings Inc.)
• Original Assignee: Viavi Solutions UK Limted (Lumentum Holdings Inc.)
• Inventors: Kenington, Peter, Randell, Nicholas James
• Granted Patent: US 9,213,079 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/02526 using non-dedicated equipment, e.g. user equipment or crowd-sourcing

Abstract

A method for geolocating a wireless communication unit. The method comprises receiving measurement data for radio frequency (RF) signals between the wireless communication unit and at least one base transceiver station, calculating an RF measurement based geolocation estimate for the wireless communication unit based at least partly on the received RF signal measurement data, obtaining geographical area data for at least one wireless coverage area visible to the wireless communication unit, determining a geolocation validation area based at least partly on the obtained geographical area data for the at least one wireless coverage area visible to the wireless communication unit, and deriving a confidence factor for the RF measurement based geolocation estimate based at least partly on the determined geolocation validation area.

Claims

1. A method for geolocating a wireless communication unit, the method comprising:

receiving measurement data for radio frequency (RF) signals between the wireless communication unit and at least one base transceiver station;

calculating an RF measurement based geolocation estimate for the wireless communication unit based at least partly on the received RF signal measurement data;

obtaining geographical area data for at least one wireless coverage area visible to the wireless communication unit;

determining a geolocation validation area based at least partly on the obtained geographical area data for the at least one wireless coverage area visible to the wireless communication unit; and

deriving a confidence factor for the RF measurement based geolocation estimate based at least partly on the determined geolocation validation area.

2. The method of claim 1, wherein the method comprises determining a geolocation validation area by calculating an area of overlap of coverage areas for the at least one wireless coverage area visible to the wireless communication unit.

3. The method of claim 2, wherein the method further comprises refining a geolocation validation area using received RF signal measurement data for at least one wireless coverage area visible to the wireless communication unit.

4. The method of claim 3, wherein the method comprises receiving signal strength information from the wireless communication unit for at least one wireless coverage area visible to the wireless communication unit, and refining the geolocation validation area based at least partly on the received signal strength information.

5. The method of claim 3, wherein the method comprises receiving link quality information from the wireless communication unit for at least one wireless coverage area visible to the wireless communication unit, and refining the geolocation validation area based at least partly on the received link quality information.

6. The method of claim 3, wherein the method further comprises:

receiving propagation delay information from the wireless communication unit for at least one wireless coverage area visible to the wireless communication unit;

estimating a distance between the wireless communication unit and the at least one wireless coverage area visible to the wireless communication unit; and

refining the geolocation validation area for the wireless communication unit within the area of overlap based at least partly on the estimated distance(s).

7. The method of claim 1, wherein the obtained geographical area data for the at least one wireless coverage area visible to the wireless communication unit comprises, for each wireless coverage area:

an indication of a geographical location representative of a central point within the wireless coverage area; and

an indication of a radius of the wireless coverage area.

8. The method of claim 1, wherein the geographical area data for the at least one wireless coverage area visible to the wireless communication unit is obtained from at least one third party database.

9. The method of claim 8, wherein the geographical area data for the at least one wireless coverage area visible to the wireless communication unit is obtained from at least one of:

at least one publicly available on-line database; and

at least one proprietary third party database.

10. The method of claim 1, wherein the obtained geographical area data comprises at least one from a group comprising at least one of:

crowd-sourced coverage data;

network planning/configuration data; and

drive test data.

11. The method of claim 1, wherein the method comprises calculating an RF measurement based geolocation estimate for the wireless communication unit by deriving a probability density function for a location of the wireless communication unit from the received RF signal measurement data and network configuration data.

12. The method of claim 1, wherein the received RF signal measurement data comprises at least one from a group comprising at least one of:

signal strength measurement data;

link quality measurement data; and

propagation delay measurement data.

13. The method of claim 1, wherein the method comprises setting the confidence factor to comprise a lower confidence value if the RF measurement based geolocation estimate is located outside the geolocation validation area, and setting the confidence factor to comprise a higher confidence value if the RF measurement based geolocation estimate is located inside the geolocation validation area.

14. The method of claim 13, wherein if the RF measurement based geolocation estimate is located outside the geolocation validation area, the further from the geolocation validation area the RF measurement based geolocation estimate is located, the lower the confidence value is set for the confidence factor.

15. The method of claim 1, wherein the method further comprises providing to a user an indication of the derived confidence factor for the RF measurement based geolocation estimate.

16. The method of claim 1, wherein, if the derived confidence factor for the RF measurement based geolocation estimate comprises a confidence value below a predetermined confidence level, the method further comprises performing at least one of:

discarding the RF measurement based geolocation estimate; and

calculating a replacement geolocation estimate for the wireless communication unit based at least partly on the geolocation validation area.

17. The method of claim 1, wherein the method comprises receiving RF signal measurement data from the wireless communication unit as part of a periodic measurement reporting process.

18. A geolocation system arranged to perform geolocation of a wireless communication unit, the geolocation system comprising at least one signal processing module arranged to:

receive measurement data for radio frequency (RF) signals between the wireless communication unit and at least one base transceiver station;

calculate an RF measurement based geolocation estimate for the wireless communication unit based at least partly on the received RF signal measurement data;

obtain geographical area data for at least one wireless coverage area visible to the wireless communication unit;

determine a geolocation validation area based at least partly on the obtained geographical area data for the at least one wireless coverage area visible to the wireless communication unit; and

derive a confidence factor for the RF measurement based geolocation estimate based at least partly on the determined geolocation validation area.

19. A cellular communication system incorporating a geolocation system in accordance with claim 18.

20. A non-transitory computer program product having computer-readable code stored thereon for programming a signal processing module to perform a method for geolocating a wireless communication unit, the code operable for:

receiving measurement data for radio frequency (RF) signals between the wireless communication unit and at least one base transceiver station;

calculating an RF measurement based geolocation estimate for the wireless communication unit based at least partly on the received RF signal measurement data;

obtaining geographical area data for at least one wireless coverage area visible to the wireless communication unit;

determining a geolocation validation area based at least partly on the obtained geographical area data for the at least one wireless coverage area visible to the wireless communication unit; and

deriving a confidence factor for the RF measurement based geolocation estimate based at least partly on the determined geolocation validation area.