Ultrawideband asynchronous tracking system and method

• US 8,116,350 B1
• Filed: 01/14/2009
• Issued: 02/14/2012
• Est. Priority Date: 01/14/2009
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Arndt, G. Dickey, Ngo, Phong H., Dusl, John, Phan, Chau T., Gross, Julia A., Ni, Jianjun
• Primary Examiner(s): Tran, Khanh C
• Assistant Examiner(s): HAILEGIORGIS, FITWI Y
• Application Number:
  US12/353,755
• Time in Patent Office: 1,126 Days
• Field of Search: 375/130, 375/267, 342/126, 342/133, 342/147, 342/465, 455/456.1, 324/318, 324/322
• US Class Current: 375/130
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A passive tracking system is provided with a plurality of ultrawideband (UWB) receivers that is asynchronous with respect to a UWB transmitter. A geometry of the tracking system may utilize a plurality of clusters with each cluster comprising a plurality of antennas. Time Difference of Arrival (TDOA) may be determined for the antennas in each cluster and utilized to determine Angle of Arrival (AOA) based on a far field assumption regarding the geometry. Parallel software communication sockets may be established with each of the plurality of UWB receivers. Transfer of waveform data may be processed by alternately receiving packets of waveform data from each UWB receiver. Cross Correlation Peak Detection (CCPD) is utilized to estimate TDOA information to reduce errors in a noisy, multipath environment.

Claims

1. An ultrawideband tracking system for tracking a position of an ultrawideband transmitter that produces a plurality of ultrawideband pulses, comprising:

a plurality of clusters, said plurality of clusters being spaced apart at a predetermined cluster separation distance from each other, wherein each of said plurality clusters is comprised of;

at least two antennas, said at least two antennas being spaced apart from each other by a predetermined antenna separation distance; and

at least one ultrawideband receiver operable for receiving said plurality of ultrawideband pulses and producing ultrawideband pulse waveforms data, wherein each of said at least one ultrawideband receiver is operably connected to said at least two antennas, wherein said at least one ultrawideband receiver is asynchronous with respect to said ultrawideband transmitter, and wherein said at least one ultrawideband receiver is programmed to divide a scan of said ultrawideband pulse waveform data into a pluralit of segments; and

at least one computer operably connected with each of said at least one ultrawideband receiver and capable of receiving said ultrawideband pulse waveform data from each of said at least one ultrawideband receiver, wherein said at least one computer is programmed to separately and near simultaneously receive multiple streams of said plurality of segments of said ultrawideband pulse waveform data from multiple ultrawideband receivers associated with said plurality of clusters until all of said plurality of segments has been received, wherein said at least one computer is programmed to utilize said ultrawideband pulse waveform data to produce time difference of arrival information for said at least two antennas for each of said plurality of clusters, wherein said at least one computer is programmed to determine an angle of arrival information from said time difference of arrival information, and wherein said at least one computer is programmed to utilize said angle of arrival information for tracking said ultrawideband transmitter,

wherein said at least one computer is programmed to interface with each of said at least one ultrawideband receiver, associated with said plurality of clusters, by creating a separate software socket for each of said at least one ultrawideband receiver whereby each separate software socket receives said ultrawideband pulse waveform data from a predetermined at least one ultrawideband receiver.

2. The ultrawideband tracking system of claim 1, wherein said at least one computer is programmed to determine said angle of arrival information from said time difference of arrival information based on a far field assumption.

3. The ultrawideband tracking system of claim 2, wherein said far field assumption comprises assuming a distance of said ultrawideband transmitter from said plurality of clusters is snore than ten times greater than said predetermined antenna separation distance.

4. The ultrawideband tracking system of claim 1, wherein said at least one computer is programmed to assemble said plurality of segments of said ultrawideband pulse waveform data from said at least one ultrawideband receiver as part of said plurality of clusters into one full representation of said ultrawideband pulse waveform data.

5. An ultrawideband tracking system for tracking a position of an ultrawideband transmitter that produces a plurality of ultrawideband pulses, comprising:

a plurality of clusters, said plurality of clusters being spaced apart at a predetermined cluster separation distance from each other, wherein each of said plurality of clusters is comprised of;

at east two antennas, said at least two antennas being spaced apart from each other by a predetermined antenna separation distance; and

at least one ultrawideband receiver operable for receiving said plurality of ultrawideband pulses and producing ultrawideband pulse waveform data wherein each of said at least one ultrawideband receiver is operably connected to said at least two antennas, wherein said at least one ultrawideband receiver is asynchronous with respect to said ultrawideband transmitter, and wherein said at least one ultrawideband receiver is programmed to divide a scan of said ultrawideband pulse waveform data into a plurality of segments, and

at least one computer operably connected with each of said at least one ultrawideband receiver and capable of receiving said ultrawideband pulse waveform data from each of said at least one ultrawideband receiver, wherein said at least one computer is programmed to separately and near simultaneously receive multiple streams of said plurality of segments of said ultrawideband pulse waveform data from multiple ultrawideband receivers associated with said plurality of clusters until all of said plurality of segments has been received, wherein said at least one computer is programmed to utilize said ultrawideband pulse waveform data to produce time difference of arrival information for said at least two antennas for each of said plurality of clusters, wherein said at least one computer is programmed to determine angle of arrival information from said time difference of arrival information, and wherein said at least one computer is programmed to utilize said angle of arrival information for racking said ultrawideband transmitter,

wherein said at least one computer is programmed to alternatively receive multiple streams of said plurality of segments of said ultrawideband pulse waveform data from multiple ultrawideband receivers associated with said plurality of clusters, wherein said capability to alternatively receive multiple streams is performed by programming multiple sections, wherein said multiple sections operate to alternatively receive data from said multiple receivers until all of said plurality of segments has been received.

6. The ultrawideband tracking system of claim 5, wherein said at least one computer is programmed to utilize peak detection on said plurality of ultrawideband pulses to determine a plurality of cross-correlation windows, and wherein said at least one computer is programmed to cross-correlate said ultrawideband pulse waveform data in said plurality of cross-correlation windows thereby estimating said time difference of arrival information.

7. A method for tracking a position of an ultrawideband transmitter which produces a plurality of ultrawideband pulses, comprising:

providing an ultrawideband tracking system comprised of;

a plurality of clusters, said plurality of clusters being spaced apart at a predetermined cluster separation distance from each other, wherein each of said plurality of clusters is comprised of;

at least two antennas said at least two antennas being spaced a art from each other by a predetermined antenna separation distance;

at least one ultrawideband receiver capable of receiving said plurality of ultrawideband pulses and capable of producing ultrawideband pulse waveform data, wherein each of said at least one ultrawideband receiver is operably connected to said at least two antennas, and wherein said at least one ultrawideband receiver is asynchronous with respect to said ultrawideband transmitter; and

at least one computer capable of interfacing with said at least one ultrawideband receiver and capable of receiving said ultrawideband pulse waveform data;

receiving said plurality of ultrawideband pulses by said at least one ultrawideband receiver associated with said plurality of clusters;

producing a plurality of ultrawideband pulse waveform data sets b said at least one ultrawideband receiver associated with said plurality of clusters;

interfacing said at least one computer with said at least one ultrawideband receiver associated with said plurality of clusters, wherein said step of interfacing is comprised of;

creating a separate software socket for each of said at least one ultrawideband receiver, wherein each separate software socket receives said ultrawideband pulse waveform data from, a predetermined at least one ultrawideband receiver;

scanning each of said plurality of ultrawideband pulse waveform data sets, wherein said step of scanning is performed by said at least one computer and is comprised of;

dividing a scan of each of said plurality of ultrawideband pulse waveform data sets into a plurality of segments; and

alternately receiving said plurality of ultrawideband pulse waveform data sets until all of said plurality of segments from all plurality of ultrawideband pulse waveform data sets has been received by said at least one computer; and

programming said at least one computer to utilize said plurality of ultrawideband pulse waveform data sets for tracking said ultrawideband transmitter, wherein said step of programming is comprised of;

utilizing said ultrawideband pulse waveform data to produce time difference of arrival information for said at least two antennas for each of said plurality of clusters;

determining angle of arrival information from said time difference of arrival information; and

utilizing said angle of arrival information for tracking said ultrawideband transmitter.

8. The method of claim 7, further comprising the step of:

programming said at least one computer to determine said angle of arrival information from said time difference of arrival information through the use of a far field assumption.

9. The method of claim 8, wherein the far field assumption comprises assuming that a distance of said ultrawideband transmitter from said plurality of clusters is more than ten times greater than said predetermined antenna separation distance.

10. The method of claim 7, wherein the step of programming is further comprised of:

detecting peaks of a plurality of pulses in said ultrawideband pulse waveform data;

determining a plurality of cross-correlation windows for said plurality of pulses; and

estimating time difference of arrival information by cross-correlating said ultrawideband pulse waveform data in said plurality of cross-correlation windows.

11. An ultrawideband tracking system for tracking a position of an ultrawideband transmitter which produces ultrawideband pulses, comprising:

a plurality of ultrawideband receivers operable for receiving said ultrawideband pulses and producing ultrawideband pulse waveform data;

at least one computer programmed to interface with said plurality of ultrawideband receivers and receive said ultrawideband else waveform data, wherein said at least one computer is programmed to utilize peak detection on said plurality of pulses in said ultrawideband pulse waveform data to determine a plurality of cross-correlation windows for said plurality of pulses, wherein said at least one computer is programmed to cross-correlate said ultrawideband pulse waveform data in said plurality of cross-correlation windows, and wherein said at least one computer estimates time difference of arrival information for use in tracking the position of said ultrawideband transmitter, wherein said at least one computer is programmed to interface with said plurality of ultrawideband receivers which divide a scan of said ultrawideband pulse waveform data into a plurality of segments and to alternately receive said ultrawideband pulse waveform data from different ones of said plurality of ultrawideband receivers until all of said plurality of segments has been received; and

a plurality of at least two antennas operably connected to each of said plurality of ultrawideband receivers, wherein said at least two antennas being spaced apart from each other by an antenna separation distance, wherein said at least one computer is programmed to utilize said ultrawideband pulse waveform data to produce said time difference of arrival information for said at least two antennas for each of said plurality of receivers, wherein said at least one computer is programmed to determine angle of arrival information from said time difference of arrival information based on a far field assumption that a distance of said ultrawideband transmitter from said plurality of clusters is more than ten times greater than said antenna separation distance, and wherein said at least one computer is programmed to utilize said angle of arrival information for tracking said ultrawideband transmitter.

12. The ultrawideband tracking system of claim 11, wherein said plurality of ultrawideband receivers is asynchronous with respect to said ultrawideband transmitter.

13. The ultrawideband tracking system of claim 11, wherein said at least one computer is programmed to interface with said plurality of ultrawideband receivers by creating a separate software socket for each of said plurality of ultrawideband receivers whereby each separate software socket receives said ultrawideband pulse waveform data from a particular one of said plurality of ultrawideband receivers.