Robust, efficient, localization system

• US 20030129996A1
• Filed: 01/17/2003
• Published: 07/10/2003
• Est. Priority Date: 05/13/1996
• Status: Active Grant

• Current Assignee: Skyhook Holding, Inc. (Liberty Broadband Corp.)
• Original Assignee: KSI Inc. (Liberty Broadband Corp.)
• Inventors: Maloney, John E., Stevenson, James O.
• Granted Patent: US 7,340,259 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• 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 characterization processing units at the first and second sensor stations, respectively, each signal characterization processing unit generating replicated signal data,

at least first and second signal correlation processing units at the first and second sensor stations, respectively, each correlation 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.

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 signal characterization processing 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 the time-tagged received signal data between at least the first sensor station and the second sensor station;

the signal characterization processing 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.

6. 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.

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

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

9. An apparatus for locating a standard, mobile-communications radio transmitter in a cellularized communications system as claimed in claim 1, wherein:

the signal characterization processing unit at at least one sensor station 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 processing unit at the at least one sensor station correlates the reconstructed signal with the replicated signal data.

10. 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.

17. 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.

11. An apparatus for measuring an angle-of-arrival of a signal from a mobile radio transmitter, comprising:

a local phased-array antenna and associated signal conditioning means for receiving a signal from the mobile radio transmitter;

a signal characterization processing unit for generating replicated signal data; and

a signal correlation processing unit at the sensor station for performing matched-replica correlation processing with the received signal data and the replicated signal data to produce an angle of arrival of the received signal.

12. An apparatus for measuring an angle-of-arrival of a signal from a mobile radio transmitter as claimed in claim 11, wherein the replicated signal data comprises prior known protocol forms of the signal from the mobile radio transmitter.

13. An apparatus for measuring an angle-of-arrival of a signal from a mobile radio transmitter as claimed in claim 11, wherein the replicated signal data comprises representative signal data derived from the received signal.

14. An apparatus for measuring an angle-of-arrival of a signal from a mobile radio transmitter as claimed in claim 11, further comprising an antenna and a signal

signal characterization processing unit that are remote from the local phased-array antenna, the remote antenna and signal characterization processing unit generating the representative signal data.

15. An apparatus for measuring an angle-of-arrival of a signal from a mobile radio transmitter as claimed in claim 11, wherein the correlation processor correlates the representative signal data for an extended integration time.

16. An apparatus as in claim 11 wherein the correlation processor correlates the received signal data to produce coefficients incorporating the inter-element phase information which are themselves used in a correlation to obtain measurements of signal angle-of-arrival (AOA) according to the relation:

18. 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 location-related signal parameters obtained at the central site; and

indicating the estimated position of the mobile transmitter.

19. A method of measuring an angle-of-arrival of a signal from a mobile radio transmitter, comprising:

receiving a signal from the mobile radio transmitter at a local phased-array antenna;

generating replicated signal data; and

performing matched-replica correlation processing with the received signal data and the replicated signal data to produce an angle of arrival of the signal from the mobile radio transmitter at the local phased-array antenna.