Method and system for relative geometry tracking utilizing multiple distributed emitter/detector local nodes and mutual local node tracking

• US 5,307,289 A
• Filed: 09/12/1991
• Issued: 04/26/1994
• Est. Priority Date: 09/12/1991
• Status: Expired due to Fees

• Current Assignee: Sesco Corporation
• Original Assignee: Sesco Corporation
• Inventors: Harris, James C.
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Pesso, Thomas
• Application Number:
  US07/758,782
• Time in Patent Office: 957 Days
• Field of Search: 364/460, 364/559, 364/516, 342/352, 342/457, 342/191, 342/356
• US Class Current: 700/90
• CPC Class Codes: G01S 5/0249 Determining position using measurements made by a non-stationary device other than the device whose position is being determined
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

A method and system for tracking various objects utilizing a plurality of sensors. Separate locations or platforms are provided with a number of sensors collocated with an energy generation/ reflection device, and also a communication device. Each of the platforms is termed local nodes of a multi-sensor fusion system, and possibly can experience relative translational and/or rotational motion in as many as three dimensions with respect to itself and with respect to similar local nodes. Each local node is capable of measuring some combination of bearing angles and/or range and/or respective derivatives from the local node to cooperative local nodes by generating or reflecting energy such that cooperative local nodes may obtain mutual sensor measurements. Information obtained or processed by each local node, including track data or track estimates, are possibly transmitted to one or more central nodes denoted as fusion centers provided with processing capabilities. In addition, when an object or multiple objects which are not local nodes are being tracked, at least one cooperative local node can measure bearing angles and/or range and/or respective derivatives from the local node to the other object. After undergoing a series of processes, sensor data from multiple local nodes are combined at the fusion centers to provide estimates of both the relative geometry and relative orientation of each cooperative local node with respect to other cooperative local nodes and the relative geometry of other sensed objects with respect to each cooperative local node. Estimated relative geometries are either range normalized or scaled with actual ranges depending upon sensor capabilities.

Claims

1. A method of tracking the relative geometry and relative orientation of two or more tracking stations, and the additional relative geometry of other objects with respect to said tracking stations utilizing at least two tracking stations and at least one fusion center, including the steps of:

sensing, at each tracking station, energy emissions arriving from other tracking stations and other objects, said energy emissions including information relating to the relative geometry of the tracking stations and the other objects;

forwarding sensor data relating to the relative geometry of each tracking station with respect to other tracking stations and with respect to other objects to a means for processing said sensor data, which determines the mutual relative geometry of each tracking station with respect to a second tracking station without utilizing attitude information local to each tracking station;

estimating components of the relative geometry of each tracking station with respect to other tracking stations and other objects, said estimating components step conducted in said processing means;

forwarding information between said means for processing said sensor data and at least one fusion center regarding the relative geometry of each tracking station with respect to other tracking stations and other objects;

estimating the relative orientation of pairs of tracking station Egocentric Coordinate Frames, said estimating step conducted in said means for processing said sensor data; and

estimating the relative geometry of triplets of two tracking stations and one other object, said estimating step conducted in said means for processing said sensor data.

2. The method in accordance with claim 1 further including the step of mapping information regarding the relative geometry, and dynamics thereof, of objects represented within the Egocentric Coordinate Frame of tracking stations onto the Egocentric Coordinate Frame of other tracking stations, and further refining estimates of the relative geometries of each tracking station with respect to other tracking stations and other objects by combining multiple estimates of objects which are represented within common Egocentric Coordinate Frames, said means for processing said sensor data.

3. The method in accordance with claim 1, wherein said step of estimating components of the relative geometry of each tracking station with respect to other tracking stations, additionally includes the step of estimating the associated dynamics of the relative geometries of each tracking station with respect to other tracking stations, said step of estimating the associated dynamics conducted in said means for processing said sensor data.

4. The method in accordance with claim 1, wherein said step of forwarding information between said means for processing said sensor data and at least one fusion center additionally includes the exchange of information regarding estimates of the dynamics of said relative geometries.

5. The method in accordance with claim 1, wherein the said step of estimating the relative orientation of pairs of Egocentric Coordinate Frames additionally includes the step of estimating the associated dynamics of said relative orientations, said additional step conducted in said means for processing said sensor data.

6. The method in accordance with claim 1, wherein the said step of estimating the relative orientation of triplets of two tracking stations additionally includes the step of estimating the associated dynamics of the relative geometry of triplets of two tracking systems, said additional step conducted in said means for processing said sensor data.

7. The method in accordance with claim 1, wherein the results of said step of estimating the relative orientation of triplets of two tracking stations are transmitted to said step of estimating components of relative geometries.

8. The method in accordance with claim 2, wherein the results of said steps of mapping information and further refining estimates of the relative geometries is forwarded to said step of estimating components of the relative geometry of each tracking station with respect to other tracking stations.

9. The method in accordance with claim 1, wherein said means for processing said sensor data is provided at any number of tracking station locations, at any number of remote locations, or at a combination of any number of tracking station locations and remote locations.

10. The method in accordance with claim 1, including the step of generating an energy beam from each of the tracking stations directed at an object other than another tracking station.

11. The method in accordance with claim 1, including the step of generating an energy beam which emanates from a tracking station and arrives at any number of other tracking stations.

12. The method in accordance with claim 11 wherein said energy beam includes a code unique to the tracking station generating said energy beam.

18. The method in accordance with claim 1 including the steps of mapping sensor data onto a coordinate frame related to the orientation of the tracking station if said tracking station does not experience rotational rigid body motion, and forwarding the data generated by this step to said processing means, said mapping sensor data onto a coordinate frame step conducted in said means for processing said sensor data.

19. The method in accordance with claim 1, wherein relative range and/or bearing and/or the respective time derivative information is estimated.

13. The method in accordance with claim including the steps of estimating any time parameters of the rotational motion of any number of the tracking stations, and forwarding the data generated by this step to said means for processing said sensor data, said step of estimating any time parameters being conducted in said means for processing said sensor data.

14. The method in accordance with claim 13, including the steps of utilizing said time parameters to map the sensor data measured by said tracking stations onto a coordinate frame referenced to an inertial reference or a pseudo-inertial reference, and forwarding the data generated by this step to said processing means, said step of utilizing said time parameters to map the sensor data conducted in said means for processing said sensor data.

15. The method in accordance with claim 13, including the steps of utilizing said time parameters to map the results of said step of estimating components of relative geometry of each tracking stations with respect to other tracking stations onto a coordinate frame referenced to an inertial reference or a pseudo-inertial reference, and forwarding the data generated by this step to said means for processing said sensor data, said step of utilizing said time parameters to map the step of estimating components conducted in said means for processing said sensor data.

16. The method in accordance with claim 14 wherein said inertial reference or said pseudo-inertial reference utilizes the angular momentum vector of said tracking station and an additional reference about said angular momentum vector, wherein said additional reference may be provided by an inertial reference or by reference to an energy source or to a field of potential energy.

17. The method in accordance with claim 15 wherein said inertial reference or said pseudo-inertial reference utilizes the angular momentum vector of said tracking station and an additional reference about said angular momentum vector, wherein said additional reference may be provided by an inertial reference or by reference to an energy source or to a field of potential energy.

20. A system for tracking the relative geometry and relative orientation of two or more tracking stations, and the additional relative geometry of other objects with respect to said tracking stations including:

any number of fusion centers including a receiver and an information processor which determines the mutual relative geometry of each tracking station with respect to a second tracking station without utilizing attitude information local to each tracking station;

the present of at least one information processor within the collection of said tracking stations and said fusion centers;

a plurality of tracking stations for sensing of information related to the relative geometry of said tracking stations and possibly other objects, each of said tracking station including,

energy generating means for directing energy emission toward at least one other tracking station;

sensing means for sensing energy emissions arriving at each of said tracking stations, said energy emissions including data relating to the relative geometry of said tracking station with respect to any combination of other tracking stations and other objects; and

communication device provided on each of said tracking stations for exchanging data with, or transmitting data to, any combination of other said tracking stations and said fusion centers.

21. The system in accordance with claim 20, wherein any number of said tracking stations also has energy generating means for directing energy emission toward at least one object other than said tracking stations.

22. The system in accordance with claim 20, wherein any number of said tracking stations has information processing means.

23. The system in accordance with claim 20, wherein any number of said fusion centers has communications transmission means.

24. The system in accordance with claim 20, wherein any number of said fusion centers is remote from each of said tracking station.

25. The system in accordance with claim 20 wherein any number of said tracking stations is provided with a means for sensing time parameters of the motion of each respective tracking station.

26. The system in accordance with claim 20, wherein each of said energy generating means generates a code unique to each of said tracking stations.

27. The system in accordance with claim 21, wherein each of said energy generating means generates a code unique to each of said tracking stations.