Method and system of providing clustered networks of bearing-measuring sensors

• US 20060227664A1
• Filed: 04/08/2005
• Published: 10/12/2006
• Est. Priority Date: 04/08/2005
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Horak, Dan T.
• Granted Patent: US 7,372,773 B2
• Time in Patent Office: Days
• US Class Current: 367/136
• CPC Class Codes: G01S 5/20 Position of source determined by a plurality of spaced direction-finders

Abstract

System and method for determining a location of a first target. The sensor network comprises a first sensor cluster comprising a first plurality of bearing measuring sensors. A first gateway is operatively coupled to the first plurality of bearing measuring sensors. A second sensor cluster comprises a second plurality of bearing measuring sensors. A second gateway is operatively coupled to the second plurality of bearing measuring sensors. A central command node is operatively coupled to the first and the second gateways. A first limited set of pre-computed numbers representative of information for generating a global target location estimation is transmitted from the first gateway to the central command node. A second limited set of pre-computed numbers representative of information for generating the global target location estimation is transmitted from the second gateway to the central command node. A global target location estimate of the first target is computed by the central command node based on the first and second limited set of pre-computed numbers.

Claims

1. A sensor network for determining a location of a first target, said sensor network comprising:

a first sensor cluster, said first cluster comprising a first plurality of bearing measuring sensors;

a first gateway operatively coupled to said first plurality of bearing measuring sensors;

a second sensor cluster, said second cluster comprising a second plurality of bearing measuring sensors;

a second gateway operatively coupled to said second plurality of bearing measuring sensors;

a central command node operatively coupled to said first and said second gateways;

a first limited set of pre-computed numbers representative of information for generating a global target location estimation, said first limited set of pre-computed numbers transmitted from said first gateway to said central command node;

a second limited set of pre-computed numbers representative of information for generating said global target location estimation, said second limited set of pre-computed numbers transmitted from said second gateway to said central command node; and

a global target location estimate of said first target computed by said central command node based on said first and said second limited set of pre-computed numbers.

2. The invention of claim 1 wherein said first limited set of pre-computed numbers includes information needed by said central command node to account for all measurements of said first target made by said first plurality of sensors.

3. The invention of claim 1 wherein said second limited set of pre-computed numbers includes information needed by said central command node to account for all measurements of said first target made by said second plurality of sensors.

4. The invention of claim 1 wherein said central command node utilizes a target location algorithm, said algorithm computes said global target location estimate of said first target based on said first and said second limited set of pre-computed numbers, said algorithm computing said estimated location of said first target as if each sensor in said first and second cluster transmitted a representative bearing estimate to said central command node.

5. The invention of claim 1 further comprising

a second target;

a third limited set of pre-computed numbers representative of information for generating a global target location estimation of said second target, said third limited set of pre-computed numbers transmitted from said first gateway to said central command node;

a fourth limited set of pre-computed numbers representative of information for generating said global target location estimation of said second target, said fourth limited set of pre-computed numbers transmitted from said second gateway to said central command node; and

a global target location estimate of said second target computed by said central command node based on said third and said fourth limited set of pre-computed numbers.

6. The invention of claim 1 wherein at least one of said first plurality of bearing measuring sensors comprises an acoustic sensor.

7. The invention of claim 1 wherein said first limited set of pre-computed numbers comprises approximately ten pre-computed numbers.

8. The invention of claim 1 wherein said first limited set of pre-computed numbers is derived in part based on the following equations:

x=[(Σ

w+Σ

a²)(Σ

b−

Σ

α

β

)+(Σ

α

−

Σ

a)(Σ

ab−

Σ

β

)]/D
y=[(Σ

v+Σ

α

²)(Σ

ab−

Σ

β

)+(Σ

α

−

Σ

a)(Σ

b+Σ

α

β

)]/D

where

D=(Σ

v+Σ

α

²)(Σ

w+Σ

a²)+Σ

α

−

Σ

a

and

Σ

a=a₁/v₁+a₂/v₂+ . . . +a_m/v_m
Σ

b=b₁/v₁+b₂/v₂+ . . . +b_m/v_m
Σ

a²=a₁²/v₁+a₂²/v₂+ . . . +a_m²/v_m
Σ

ab=a₁b₁/v₁+a₂b₂/v₂+ . . . +a_mb_m/v_m
Σ

v=1/v₁+1/v₂+ . . . +1/v_m
Σ

α

=α

₁/w₁+α

₂/w₂+ . . . +α

_n/w_n
Σ

β

=β

₁/w₁+β

₂/w₂+ . . . +β

_n/w_n
Σ

α

²=α

₁²/w₁α

₂²/w₂+ . . . +α

_n²/w_n
Σ

α

β

=α

₁β

₁/w₁+α

₂β

₂/w₂+ . . . +α

_nβ

_n/w_n
Σ

w=1/w₁+1/w₂+ . . . +1/w_n

9. The invention of claim 1 wherein said first limited set of pre-computed numbers is periodically transmitted from said first gateway to said central command node.

10. The invention of claim 1 wherein said first target location estimate is periodically computed by said central command node based in part on said first and said second limited set of pre-computed numbers.

11. The invention of claim 1 wherein said first plurality of sensors comprise at least 100 sensors.

12. The invention of claim 1 wherein said first target comprises a ground asset.

13. The invention of claim 1 wherein said first target comprises an airborne asset.

14. The invention of claim 1 wherein said computing node is stationary.

15. A method of computing a location of a first target in a sensor network, said method comprising the steps of:

defining a first network cluster with a first plurality of bearing measuring sensors;

operatively coupling said first network cluster to a first gateway;

defining a second network cluster with a second plurality of bearing measuring sensors;

operatively coupling said second network cluster to a second gateway;

operatively coupling said first and said second gateway to a central command node;

transmitting a first set of pre-computed numbers representative of information needed for global target location estimation of said first target from said first gateway to said central command node; and

transmitting a second set of pre-computed numbers representative of information needed for global target location estimation of the first target from said second gateway to said central command node; and

estimating said location of said first target by said central command node based in part on said first and said second limited set of pre-computed numbers.

16. The invention of claim 15 wherein said first limited set of pre-computed numbers includes information needed by said central command node to account for all measurements of said first target made by said first plurality of sensors.

17. The invention of claim 15 wherein said second limited set of pre-computed numbers includes information needed by said central command node to account for all measurements of said first target made by said second plurality of sensors.

18. The invention of claim 15, further comprising the step of

utilizing a target location algorithm, said algorithm computes said global target location estimate of said first target based on said first and said second limited set of pre-computed numbers, said algorithm computing said estimated location of said first target as if each sensor in said first and second cluster transmitted a representative bearing estimate to said central command node.

19. The invention of claim 15 further comprising the steps of

transmitting a third set of pre-computed numbers representative of information needed for global target location estimation of a second target from said first gateway to said central command node;

transmitting a fourth set of pre-computed numbers representative of information needed for global target location estimation of said second target from said second gateway to said central command node; and

estimating said location of said second target by said central command node based in part on said third and said fourth limited set of pre-computed numbers.

20. The invention of claim 15 wherein at least one of said first plurality of bearing measuring sensors comprises an acoustic sensor.

21. The invention of claim 15 wherein said first limited set of pre-computed numbers comprises approximately ten pre-computed numbers.

22. The invention of claim 15 further comprising the step of

computing said first limited set of pre-computed numbers in part based on the following equations:

x=[(Σ

w+Σ

a²)(Σ

b+Σ

α

β

)+(Σ

α

−

Σ

a)(Σ

ab−

Σ

β

)]/D
y=[(Σ

v+Σ

α

²)(Σ

ab−

Σ

β

)+(Σ

α

−

Σ

a)(Σ

b+Σ

α

β

)]/D

where

D=(Σ

v+Σ

α

²)(Σ

w+Σ

a²)+Σ

α

−

Σ

a

and

Σ

a=a₁/v₁+a₂/v₂+ . . . +a_m/v_m
Σ

b=b₁/v₁+b₂/v₂+ . . . +b_m/v_m
Σ

a²=a₁²/v₁+a₂²/v₂+ . . . +a_m²/v_m
Σ

ab=a₁b₁/v₁+a₂b₂/v₂+ . . . +a_mb_m/v_m
Σ

v=1/v₁+1/v₂+ . . . +1/v_m
Σ

α

=α

₁/w₁+α

₂/w₂+ . . . +α

_n/w_n
Σ

β

=β

₁/w₁+β

₂/w₂+ . . . +β

_n/w_n
Σ

α

²=α

₁²/w₁α

₂²/w₂+ . . . +α

_n²/w_n
Σ

α

β

=α

₁β

₁/w₁+α

₂β

₂/w₂+ . . . +α

_nβ

_n/w_n
Σ

w=1/w₁+1/w₂+ . . . +1/w_n

23. The invention of claim 15 further comprising the step of

periodically transmitting said first limited set of pre-computed numbers from said first gateway to said central command node.

24. The invention of claim 15 further comprising the step of

periodically computing said first target location estimate by said central command node based on said first and said second limited set of pre-computed numbers.