Mobile geolocation
A method and apparatus for generating reference signatures for use in geolocation in a cellular wireless communication system is provided. A first signature for a mobile communication unit comprises location information, a timestamp, and radio frequency measurement information obtained by a mobile communication unit at a location, but does not contain identification information for the mobile communication unit. The first signature is compared to signatures in a database, to identify a second signature that has a timestamp and radio frequency measurement information that correspond to those of the first signature. A reference signature is created by combining at least a part of the first signature with at least a part of the second signature. Repetition of the comparison and combination steps creates a database of reference signatures, for use in geolocating other received call signatures.
1. A method comprising:
obtaining, by a device, a signature associated with a mobile communication unit,
the signature including identification information of the mobile communication unit, non-radio frequency control information, and a first timestamp,
the signature not including location information,
identifying, by the device, a first reference signature in a reference signature database based on the identification information,
the first reference signature including first location information, a second timestamp indicating a time before the first timestamp, and radio frequency information,
identifying, by the device, a second reference signature in the reference signature database based on the identification information,
the second reference signature including second location information, a third timestamp indicating a time after the first timestamp, and radio frequency information,
interpolating, by the device, the first location information from the first reference signature and the second location information from the second reference signature to provide a location estimate associated with the signature,
creating, by the device, a third reference signature by combining information identifying the location estimate and at least a part of the signature,
the third reference signature being for use in geolocation in a wireless communication system.
2. The method of claim 1 , further comprising:
adding the third reference signature to the reference signature database.
3. The method of claim 1 , where the signature is obtained from a first database that includes signatures that do not include location information, and
where the first reference signature and the second reference signature are created by combining signatures from the first database with anonymized signatures of a second database,
the anonymized signatures including location information.
4. The method of claim 3 , where the first database is an Operation Support System database of the wireless communication system.
5. The method of claim 1 , where the non-radio frequency control information includes at least one of:
channel quality index information,
burst rate information, or
serving cell information.
6. The method of claim 1 , where the interpolating includes:
determining a spatial separation between a first location, indicated by the first location information, and a second location, indicated by the second location information,
generating the location estimate based on:
the spatial separation, and
a ratio of a first time difference between the first timestamp and the second timestamp and a second time difference between the second timestamp and the third timestamp.
7. The method of claim 1 , where the third reference signature includes the identification information of the mobile communication unit, the non-radio frequency control information, and the information identifying the location estimate.
8. A device comprising:
one or more processors to:
obtain a signature associated with a mobile communication unit,
the signature including identification information of the mobile communication unit, non-radio frequency control information, and a first timestamp,
the signature not including location information,
identify a first reference signature in a reference signature database based on the identification information,
the first reference signature including first location information, a second timestamp indicating a time before the first timestamp, and radio frequency information,
identify a second reference signature in the reference signature database based on the identification information,
the second reference signature including second location information, a third timestamp indicating a time after the first timestamp, and radio frequency information,
interpolate or extrapolate at least one of the first location information from the first reference signature or the second location information from the second reference signature to provide a location estimate associated with the signature,
create a third reference signature by combining information identifying the location estimate and at least a part of the signature,
the third reference signature being for use in geolocation in a wireless communication system.
9. The device of claim 8 , where the one or more processors are further to:
add the third reference signature to the reference signature database.
10. The device of claim 8 , where the signature is obtained from a first database that includes signatures that do not include location information, and
where the first reference signature and the second reference signature are created by combining signatures from the first database with anonymized signatures of a second database,
the anonymized signatures including location information.
11. The device of claim 10 , where the first database is an Operation Support System database of the wireless communication system.
12. The device of claim 8 , where the non-radio frequency control information includes at least one of:
channel quality index information,
burst rate information, or
serving cell information.
13. The device of claim 8 , where the one or more processors, when interpolating or extrapolating, are to:
interpolate the first location information from the first reference signature and the second location information from the second reference signature to provide the location estimate associated with the signature.
14. The device of claim 8 , where the one or more processors, when interpolating or extrapolating, are to:
extrapolate the first location information from the first reference signature or the second location information from the second reference signature to provide the location estimate associated with the signature.
15. A non-transitory computer-readable medium storing instructions, the instructions comprising:
one or more instructions that, when executed by a device, cause the device to:
obtain a signature associated with a mobile communication unit,
the signature including identification information of the mobile communication unit, non-radio frequency control information, and a first timestamp,
the signature not including location information,
identify a reference signature in a reference signature database based on the identification information,
the reference signature including first location information, a second timestamp indicating a time before or after the first timestamp, and radio frequency information,
extrapolate, by the device, the first location information from the reference signature to provide a location estimate associated with the signature,
create, by the device, a second reference signature by combining information identifying the location estimate and at least a part of the signature,
the second reference signature being for use in geolocation in a wireless communication system.
16. The non-transitory computer-readable medium of claim 15 , where the one or more instructions further cause the device to:
add the second reference signature to the reference signature database.
17. The non-transitory computer-readable medium of claim 15 , where the signature is obtained from a first database that includes signatures that do not include location information, and
where the reference signature is created by combining another signature from the first database with an anonymized signature of a second database,
the anonymized signature including the first location information.
18. The non-transitory computer-readable medium of claim 17 , where the first database is an Operation Support System database of the wireless communication system.
19. The non-transitory computer-readable medium of claim 15 , where the non-radio frequency control information includes at least one of:
channel quality index information,
burst rate information, or
serving cell information.
20. The non-transitory computer-readable medium of claim 15 , where the second reference signature includes the identification information of the mobile communication unit, the non-radio frequency control information, and the information identifying the location estimate.