System and method for the mitigation of multipath and the improvement of signal-to-noise ratios in time division multiple access(tdma) location networks

• US 20060012521A1
• Filed: 09/19/2003
• Published: 01/19/2006
• Est. Priority Date: 09/20/2002
• Status: Active Grant

• Current Assignee: David Small
• Original Assignee: David Small
• Inventors: Small, David
• Granted Patent: US 7,652,625 B2
• Time in Patent Office: Days
• US Class Current: 342/386
• CPC Class Codes: G01S 5/0215 Interference
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0247 Determining attitude
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0848 Joint weighting

Abstract

A positioning system that includes a plurality of chronologically synchronized Time Division Multiple Access (TDMA) Positioning-Unit Devices and a position receiver incorporating a TDMA Adaptive Directional Antenna Array is disclosed. The plurality of chronologically synchronized Positioning-Unit Devices, positioned at known locations, transmit positioning signals in a predetermined Time Division Multiple Access (TDMA) sequence, such that each Positioning-Unit Device has a unique transmission time slot. The TDMA Adaptive Directional Antenna Array is configured to consecutively steer a directional receive antenna in spatial synchronization with the plurality of Time Division Multiple Access (TDMA) Positioning-Unit Device transmissions, such that the directional receive antenna is oriented toward the currently transmitting Positioning-Unit Device, or the directional receive antenna is oriented toward the origin of the currently received positioning signal. The TDMA Adaptive Directional Antenna Array is controlled by a deterministic algorithm based on the knowledge of the Positioning-Unit Device locations, TDMA Adaptive Directional Antenna Array location, TDMA Adaptive Directional Antenna Array attitude, network Time Division Multiple Access (TDMA) transmission sequencing, Positioning-Unit Device positioning signal propagation delays, and network time.

Claims

1. A method for mitigating multipath and improving received signal-to-noise ratios in a Time Division Multiple Access location network, the method comprising:

a) deploying a plurality of chronologically synchronized positioning-unit devices, positioned at known locations, and transmitting positioning signals in a predetermined Time Division Multiple Access sequence, such that each said positioning-unit device transmits a unique positioning signal in a unique transmission time slot;

b) deploying a position receiver configured with a directionally agile beam antenna;

c) receiving and interpreting said unique positioning signals to determine directionally agile beam antenna circumstance;

d) consecutively steering said directionally agile beam antenna, based on said determined directionally agile beam antenna circumstance, in spatial synchronization with said Time Division Multiple Access positioning-unit device positioning signal transmissions,

such that said directionally agile beam antenna directional gain pattern remains oriented toward the currently transmitting positioning-unit device, or remains oriented toward the origin of the currently received positioning-unit device positioning signal.

2. The method of claim 1, wherein said directionally agile beam antenna circumstance may include determination of one or more input variables selected from the group consisting of positioning-unit device locations, positioning-unit device Time Division Multiple Access transmission sequences, directionally agile beam antenna position, positioning-unit device positioning signal propagation delays, and network time.

3. The method of claim 1, wherein said spatial synchronization may be offset from network time in order to allow for positioning-unit device positioning signal propagation delays.

4. A method for mitigating multipath and improving received signal-to-noise ratios in a Time Division Multiple Access location network, the method comprising:

a) deploying a plurality of chronologically synchronized positioning-unit devices, positioned at known locations, and transmitting positioning signals in a predetermined Time Division Multiple Access sequence, such that each said positioning-unit device transmits a unique positioning signal in a unique transmission time slot;

b) deploying a position receiver configured with a directionally agile beam antenna, and an attitude determination means to provide attitude data for said directionally agile beam antenna;

c) receiving and interpreting said unique positioning signals and said attitude data to determine directionally agile beam antenna circumstance;

d) consecutively steering said directionally agile beam antenna, based on said determined directionally agile beam antenna circumstance, in spatial synchronization with said Time Division Multiple Access positioning-unit device positioning signal transmissions,

such that said directionally agile beam antenna directional gain pattern remains oriented toward the currently transmitting positioning-unit device, or remains oriented toward the origin of the currently received positioning-unit device positioning signal.

5. The method of claim 4, wherein said directionally agile beam antenna circumstance may include determination of one or more input variables selected from the group consisting of positioning-unit device locations, positioning-unit device Time Division Multiple Access transmission sequences, directionally agile beam antenna position, directionally agile beam antenna attitude, positioning-unit device positioning signal propagation delays, and network time.

6. The method of claim 4, wherein said spatial synchronization may be offset from network time in order to allow for positioning-unit device positioning signal propagation delays.

7. A system configured to mitigate multipath and improve received signal-to-noise ratios in a Time Division Multiple Access location network, the system comprising:

a) a plurality of chronologically synchronized positioning-unit devices, positioned at known locations, and configured to transmit positioning signals in a predetermined Time Division Multiple Access sequence, such that each said positioning-unit device transmits a unique positioning signal in a unique transmission time slot;

b) a position receiver configured with a directionally agile beam antenna, configured to consecutively steer a directional gain pattern in a plurality of directions;

c) said position receiver configured to receive and interpret said unique positioning signals to determine directionally agile beam antenna circumstance;

e) said directionally agile beam antenna configured to consecutively steer said directional gain pattern, based on said determined directionally agile beam antenna circumstance, in spatial synchronization with said Time Division Multiple Access positioning-unit device positioning signal transmissions,

such that said directionally agile beam antenna directional gain pattern remains oriented toward the currently transmitting positioning-unit device, or remains oriented toward the origin of the currently received positioning-unit device positioning signal.

8. The system of claim 7, wherein said directionally agile beam antenna circumstance may include determination of one or more input variables selected from the group consisting of positioning-unit device locations, positioning-unit device Time Division Multiple Access transmission sequences, directionally agile beam antenna position, positioning-unit device positioning signal propagation delays, and network time.

9. The system of claim 7, wherein said spatial synchronization may be offset from network time in order to allow for positioning-unit device positioning signal propagation delays.

10. A system configured to mitigate multipath and improve received signal-to-noise ratios in a Time Division Multiple Access location network, the system comprising:

a) a plurality of chronologically synchronized positioning-unit devices, positioned at known locations, and configured to transmit positioning signals in a predetermined Time Division Multiple Access sequence, such that each said positioning-unit device transmits a unique positioning signal in a unique transmission time slot;

b) a position receiver configured with a directionally agile beam antenna, configured to consecutively steer a directional gain pattern in a plurality of directions;

c) an attitude determination means configured to provide attitude data for said directionally agile beam antenna;

d) said position receiver configured to receive and interpret said unique positioning signals and said attitude data to determine directionally agile beam antenna circumstance;

e) said directionally agile beam antenna configured to consecutively steer said directional gain pattern, based on said determined directionally agile beam antenna circumstance, in spatial synchronization with said Time Division Multiple Access positioning-unit device positioning signal transmissions,

such that said directionally agile beam antenna directional gain pattern remains oriented toward the currently transmitting positioning-unit device, or remains oriented toward the origin of the currently received positioning-unit device positioning signal.

11. The system of claim 10, wherein said directionally agile beam antenna circumstance may include determination of one or more input variables selected from the group consisting of positioning-unit device locations, positioning-unit device Time Division Multiple Access transmission sequences, directionally agile beam antenna position, directionally agile beam antenna attitude, positioning-unit device positioning signal propagation delays, and network time.

12. The system of claim 10, wherein said spatial synchronization may be offset from network time in order to allow for positioning-unit device positioning signal propagation delays.