SYSTEM AND METHOD FOR POSITIONING IN CONFIGURED ENVIRONMENTS

• US 20090256750A1
• Filed: 02/17/2009
• Published: 10/15/2009
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Original Assignee: Loctronix Corp. (Comtech Telecommunications Corporation)
• Inventors: Mathews, Michael B., Gold, Kenn L., MacDoran, Peter F.
• Granted Patent: US 7,916,074 B2
• Time in Patent Office: Days
• US Class Current: 342/450
• CPC Class Codes: G01S 19/11 wherein the cooperating elements are pseudolites or satellite radio beacon positioning system signal repeaters
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

The present invention relates to a system and method for providing location determination in a configured environment in which Global Navigation Satellite System Signals are not available. In this regard, local beacon systems generate spread spectrum CDMA signals that are received by spectral compression units that derive physically meaningful observations without a requirement for correlation of the intercepted energy by means of the known spreading codes. The invention can coexist with communication assets already in place, and the design allows for self calibration, which simplifies installation and usage. The invention has utility in applications in which GNSS signals are unavailable or limited, for example, in warehouse inventory management, in search and rescue operations and in asset tracking in indoor environments.

Claims

1. A system for providing physical state information within a configured environment, comprising:

at least one emitter that emits energy within a transmission medium;

at least one interceptor that receives energy propagated through a transmission medium from the at least one emitter, wherein the interceptor is configured to

process the received emissions using spectral compression to produce a set of observables suitable for physical state estimation; and

communicate the set of observables to a physical state estimator; and

a physical state estimator configured to

determine at least one member of the relative physical state between the interceptor and emitter based on the set of observables received from the at least one interceptor; and

report the at least one member of the relative physical state based on the set of observables received from at least one interceptor.

2. The system of claim 1, wherein the transmission medium is comprised of at least one of a free space, gas and a weak plasma.

3. The system of claim 1, wherein the transmission medium is comprised of solid material.

4. The system of claim 1, wherein the transmission medium is comprised of a liquid.

5. The system of claim 1, wherein the interceptor is configured to simultaneously receive both structured and unstructured energy emissions.

6. The system of claim 5, wherein the energy emission comprises a structured signal having predetermined general characteristics that can be represented within the system configuration.

7. The system of claim 6, wherein the structured energy emission comprises a positioning and navigation signal.

8. The system of claim 7, wherein the structured energy emission comprises a signal within a Global Navigation Satellite System.

9. The system of claim 6, wherein the structured energy emission comprises a communications signal.

10. The system of claim 5, wherein the energy emission comprises an unstructured signal having general characteristics that are not predetermined.

11. The system of claim 10, wherein the energy emission comprises electromagnetic energy.

12. The system of claim 11, wherein the electromagnetic energy is in the radio frequency or optical bands.

13. The system of claim 10, wherein the energy emission comprises acoustic energy.

14. The system of claim 1, wherein the emitter is explicitly deployed for the purpose of physical state estimation in the configured environment.

15. The system of claim 1, wherein spectral compression comprises extracting at least one known physical characteristic of the energy emission from the emitter.

16. The system of claim 15, wherein the extraction of at least one known physical characteristic of the energy emission from the emitter occurs without regard to modulated information content of the energy emission.

17. The system of claim 1, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the intercepted energy as it propagates through a transmission medium without regard to the preservation of information content modulated within the energy emissions.

18. The system of claim 1, wherein the physical state estimator is configured to

reference stored configuration data;

and

use the referenced stored configuration data in determining the at least one member of the relative physical state between the interceptor and emitter based on the set of observables received from the interceptor

19. A method for providing physical state information within a configured environment, comprising:

emitting energy from at least one emitter through a propagation medium;

intercepting the energy emission at least one interceptor;

processing the received energy emission using spectral compression to produce a set of observables associated with the emission;

receiving configuration data pertaining to the deployment and configuration of at least one of the emitter and interceptor within the configured environment;

determining at least one member of the relative physical state between the interceptor and emitter based on the set of observables and the configuration data; and

reporting the at least one member of the relative physical state.

20. The method of claims 19, wherein the set of observables associated with the emission is suitable for physical state estimation.

21. The method of claims 19, wherein the set of observables associated with the emission is used for determining at least one physical characteristics of the emission through the propagation medium.

22. The method of claim 19, wherein processing the received energy emission using spectral compression to produce a set of observables associated with the emission is performed by squaring the energy emission recovering second harmonic amplitude, frequency and phase of the suppressed carrier.

23. The method of claim 19, wherein processing the received energy emission using spectral compression to produce a set of observables associated with the emission is performed by delay and multiply recovery of the characteristics comprising frequency, amplitude and phase of at least one periodic modulation defined over an interval of time within the energy emission.

24. The method of claim 19, wherein processing the received energy emission using spectral compression to produce a set of observables associated with the emission is performed by bandwidth synthesis where at least two modulations within the energy emission are multiplied together to recover the frequency, amplitude and phase of the frequency of the differential carriers or modulated sub-carriers.

25. The method of claim 19, wherein processing the received energy emission using spectral compression to produce a set of observables associated with the emission uses differentiation to recover the frequency, amplitude, and phase any periodic modulations over a defined interval of time.

26. The method of claim 19, wherein

the energy emission from an emitter is intercepted by first and second interceptors;

and

processing the received energy emission using spectral compression to produce a set of observables associated with the emission is performed by cross-correlation of the emissions intercepted by the first and second interceptors to produce an interferometric response comprising the amplitude, phase and temporal derivatives between the two interceptors.

27. The method of claim 26, wherein

the cross-correlation is performed on at least two distinct frequency channels of the energy emission;

and

processing proceeds by differencing the two interferometric responses to yield a new amplitude, phase and temporal derivatives between the two channels such that the phase ambiguity interval is determined by the inter-channel frequency separation.

28. The method of claim 27, wherein the cross-correlation is performed by offsetting in time the energy emission intercepted by the first interceptor with respect to the energy emission intercepted by the second interceptor as a function of the difference in physical state between the first interceptor and the second interceptor.

29. The method of claim 19, wherein the set of observables produced using spectral compression includes at least one of the physical characteristics in the form of amplitude, phase and temporal derivatives of the received energy as it propagates through a transmission medium without regard to the preservation of information content modulated within the energy emissions.

30. The method of claim 19, wherein determining the relative physical state of the emitter using the set of observables and configuration data comprises:

estimating the physical state of at least one of the emitter and the interceptor relative to a designated reference point; and

calibrating the physical state of the reference point relative to the configured environment using the configuration data.

31. The method of claim 19, further comprising:

estimating the physical state of at least one of the emitter and the interceptor relative to a designated reference point; and

updating configuration data pertaining to the deployment and configuration of at least one of the emitter and interceptor within the configured environment.

32. The method of claim 19, wherein within the configured environment

at least one of the emitter or interceptor is designated as a reference point wherein at least one member of the physical state of the reference point is predetermined;

and

at least one of the emitter or interceptor is designated a physical state sensor wherein the physical state of the physical state sensor is determined relative to the physical state of the reference point.

33. The method of claim 32, wherein

the physical state sensor is designated as a second reference point;

and

at least one of the emitter or interceptor is designated a second physical state sensor wherein the physical state of the second physical state sensor is determined relative to the physical state of the second reference point.

34. The method of claim 32, where the physical state of the reference point is calibrated relative to an external reference such that the physical state of the physical state sensor can be estimated relative to an external reference frame.

35. The method of claim 32, where a plurality of reference points are assigned to a zone such that the relative physical states of all reference points in the zone are calibrated with respect to each other.