Robust, efficient, localization system

• US 6,047,192 A
• Filed: 05/13/1997
• Issued: 04/04/2000
• Est. Priority Date: 05/13/1996
• Status: Expired due to Term

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: KSI Inc. (Liberty Broadband Corp.)
• Inventors: Maloney, John E., Stevenson, James O.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US08/855,589
• Time in Patent Office: 1,057 Days
• Field of Search: 455/405, 455/440, 455/441, 455/446, 342/362, 342/378, 342/456, 342/457, 342/461, 342/450, 342/417, 342/387, 342/388
• US Class Current: 455/456.2
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

Replica correlation processing, and associated representative signal-data reduction and reconstruction techniques, are used to detect signals of interest and obtain robust measures of received-signal parameters, such as time differences of signal arrival and directional angles of arrival, that can be used to estimate the location of a cellularized-communications signal source. The new use in the present invention of signal-correlation processing for locating communications transmitters. This enables accurate and efficient extraction of parameters for a particular signal even in a frequency band that contains multiple received transmissions, such as occurs with code-division-multiple-access (CDMA) communications. Correlation processing as disclosed herein further enables extended processing integration times to facilitate the effective detection of desired communications-signal effects and replication measurement of their location-related parameters, even for the communications signals modulated to convey voice conversations or those weakened through propagation effects. Using prior, constructed, signal replicas in the correlation processing enables elimination of the inter-site communications of the signal representations that support the correlation analyses. Reduced-data representations of the modulated signals for voiced conversation, or for the variable components of data communications, are used to significantly reduce the inter-site communications that support the correlation analyses.

Claims

1. An apparatus for locating a standard, mobile-communications, radio transmitter in a cellularized communications system, comprising:

at least first and second sensor stations, each sensor station having an antenna and associated signal conditioning means for receiving a signal from the mobile radio transmitter and a timing mechanism to time-tag an identified, representative instant of the received signal to produce time-tagged received signal data;

at least first and second signal replica units at the first and second sensor stations, respectively, each signal replica unit providing replicated signal data,

at least first and second signal correlation and measurement extraction processing units at the first and second sensor stations, respectively, each correlation and measurement extraction processing unit performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

a communications system for communicating the location-related signal parameters from the first and second sensor stations to a central site;

means for estimating the position of the mobile transmitter from the location-related signal parameters produced at only the first and second sensor stations; and

an output for indicating the estimated position of the mobile transmitter,

wherein

the signal replica unit at at least the first sensor station comprises a reduction mechanism to reduce the time-tagged received signal data,

the communications system communicates the reduced time-tagged received signal data between at least the first sensor station and the second sensor station, and

the signal replica unit at at least the second sensor station comprises a reconstruction mechanism to reconstruct the reduced time-tagged received signal data and to use the reconstructed time-tagged received data as the replicated signal data.

2. An apparatus for locating a standard, mobile-communications, radio transmitter in a cellularized communications system as claimed in claim 1, wherein the location-related signal parameters comprise times-of-arrival information.

3. An apparatus for locating a standard, mobile-communications, radio transmitter in a cellularized communications system as claimed in claim 1, wherein the location-related signal parameters comprise time-differences-of-arrival parameters.

4. An apparatus for locating a standard, mobile-communications, radio transmitter in a cellularized communications system as claimed in claim 1, wherein the location-related signal parameters comprise angle-of-arrival information.

5. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system as claimed in claim 1, wherein the replicated signal data comprises control information of the cellularized communications system.

6. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system as claimed in claim 5, wherein the control information includes overhead information on a voice channel.

7. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system as claimed in claim 5, wherein the control information includes control channel data.

8. An apparatus for locating a standard, mobile-communications, radio transmitter in a cellularized communications system as in claim 1, further comprising means for estimating motion of the mobile transmitter.

9. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system as claimed in claim 1, wherein the signal replication data is selected from among the group consisting of:

prior known protocol forms of the received signal, representative signal data derived from the received signal, voice channel signals, and digital data information.

10. An apparatus as claimed in claim 1, wherein the replicated signal data comprises voice related data.

11. An apparatus according to claim 1, wherein the replicated signal data comprises information received over a traffic channel.

12. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system, comprising:

at least first and second sensor stations, each sensor station having an antenna and associated signal conditioning means for receiving a signal from the mobile radio transmitter and a timing mechanism to time-tag an identified, representative instant of the received signal to produce time-tagged received signal data;

at least first and second signal replica units at the first and second sensor stations, respectively, each signal replica unit providing replicated signal data,

at least first and second signal correlation and measurement extraction processing units at the first and second sensor stations, respectively, each correlation and measurement extraction processing unit performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

a communications system for communicating the location-related signal parameters from the first and second sensor stations to a central site;

means for estimating the position of the mobile transmitter from the location-related signal parameters produced at only the first and second sensor stations; and

an output for indicating the estimated position of the mobile transmitter,

wherein

the signal replica unit at at least one sensor station of the first and second sensor stations comprises a reduction mechanism to reduce the signal from the mobile radio transmitter and a reconstruction mechanism to reconstruct the signal from the mobile radio transmitter from a reduced data representation, and

the signal correlation and measurement extraction processing unit at the at least one sensor station correlates the reconstructed signal with the replicated signal data.

13. A method of locating a standard, mobile-communications, radio transmitter in a cellularized communications system, comprising:

receiving a signal from the mobile radio transmitter at at least first and second sensor stations;

time-tagging an identified, representative instant of the received signal to produce time-tagged received signal data;

generating replicated signal data at the first and second sensor stations,

performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

communicating the location-related signal parameters from the first and second sensor stations to a central site;

estimating the position of the mobile transmitter from the enhanced location-related signal parameters produced by only the first and second sensor stations and obtained at the central site; and

indicating the estimated position of the mobile transmitter,

wherein the step of generating replicated signal data at the first and second sensor stations further comprises the steps of

reducing the time-tagged received signal data at at least the first sensor station,

communicating the reduced the time-tagged received signal data between at least the first sensor station and the second sensor station, and

reconstructing the reduced time-tagged received signal data at at least the second sensor station, and

wherein the step of performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters, further comprises the step of

using the reconstructed time-tagged received data as the replicated signal data at at least the second sensor station.

14. A system for locating a mobile radio transmitter, comprising:

at least first and second sensor stations, each sensor station having an antenna for receiving a signal from the mobile radio transmitter and a timing mechanism to time-tag an identified, representative instant of the received signal to produce time-tagged received signal data;

at least first and second signal replica units at the first and second sensor stations, respectively, each signal replica unit providing replicated signal data,

at least first and second signal correlation and measurement extraction processing units at the first and second sensor stations, respectively, each correlation and measurement extraction processing unit performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

a communications system for communicating the location-related signal parameters from the sensor stations to a central site;

means for estimating the position of the mobile transmitter from the location-related signal parameters; and

an output for indicating the estimated position of the mobile transmitter,

wherein

the signal replica unit at at least the first sensor station comprises a reduction mechanism to reduce the time-tagged received signal data,

the communications system communicates the reduced time-tagged received signal data between at least the first sensor station and the second sensor station, and

the signal replica unit at at least the second sensor station comprises a reconstruction mechanism to reconstruct the reduced time-tagged received signal data and to use the reconstructed time-tagged received data as the replicated signal data,

wherein the location-related signal parameters comprise angle-of-arrival information.

15. An system for locating a mobile radio transmitter, comprising:

at least first and second sensor stations, each sensor station having an antenna for receiving a signal from the mobile radio transmitter and a timing mechanism to time-tag an identified, representative instant of the received signal to produce time-tagged received signal data;

at least first and second signal replica units at the first and second sensor stations, respectively, each signal replica unit providing replicated signal data,

at least first and second signal correlation and measurement extraction processing units at the first and second sensor stations, respectively, each correlation and measurement extraction processing unit performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

a communications system for communicating the location-related signal parameters from the sensor stations to a central site;

means for estimating the position of the mobile transmitter from the location-related signal parameters; and

an output for indicating the estimated position of the mobile transmitter,

wherein

the signal replica unit at at least the first sensor station comprises a reduction mechanism to reduce the time-tagged received signal data,

the communications system communicates the reduced time-tagged received signal data between at least the first sensor station and the second sensor station, and

the signal replica unit at at least the second sensor station comprises a reconstruction mechanism to reconstruct the reduced time-tagged received signal data and to use the reconstructed time-tagged received data as the replicated signal data,

wherein the replicated signal data comprises voice related data.

16. A system according to claim 15, wherein the location-related signal parameters comprise times-of-arrival information.

17. A system according to claim 15, wherein the location-related signal parameters comprise time-differences-of-arrival parameters.

18. An system according to claim 15, wherein the location-related signal parameters comprise angle-of-arrival information.

19. A method of locating a standard, mobile-communications, radio transmitter in a cellularized communications system, comprising:

receiving a signal from the mobile radio transmitter at at least first and second sensor stations;

time-tagging an identified, representative instant of the received signal to produce time-tagged received signal data;

generating replicated signal data at the first and second sensor stations,

performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

communicating the location-related signal parameters from the sensor stations to a central site;

estimating the position of the mobile transmitter from the enhanced location-related signal parameters obtained at the central site; and

indicating the estimated position of the mobile transmitter,

wherein the step of generating replicated signal data at the first and second sensor stations further comprises the steps of

reducing the time-tagged received signal data at at least the first sensor station,

communicating the reduced the time-tagged received signal data between at least the first sensor station and the second sensor station, and

reconstructing the reduced time-tagged received signal data at at least the second sensor station, and

wherein the step of performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters, further comprises the step of

using the reconstructed time-tagged received data as the replicated signal data at at least the second sensor station,

wherein the location-related signal parameters comprise angle-of-arrival information.

20. A method of locating a standard, mobile-communications, radio transmitter in a cellularized communications system, comprising:

receiving a signal from the mobile radio transmitter at at least first and second sensor stations;

time-tagging an identified, representative instant of the received signal to produce time-tagged received signal data;

generating replicated signal data at the first and second sensor stations,

performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters;

communicating the location-related signal parameters from the sensor stations to a central site;

estimating the position of the mobile transmitter from the enhanced location-related signal parameters obtained at the central site; and

indicating the estimated position of the mobile transmitter,

wherein the step of generating replicated signal data at the first and second sensor stations further comprises the steps of

reducing the time-tagged received signal data at at least the first sensor station,

communicating the reduced the time-tagged received signal data between at least the first sensor station and the second sensor station, and

reconstructing the reduced time-tagged received signal data at at least the second sensor station, and

wherein the step of performing matched-replica correlation processing with the time-tagged received signal data and the replicated signal data to produce location-related signal parameters, further comprises the step of

using the reconstructed time-tagged received data as the replicated signal data at at least the second sensor station,

wherein the replicated signal data comprises voice related data.