System and method for measuring characteristics of a continuous medium and/or localized targets using multiple sensors

• US 7,336,222 B2
• Filed: 06/23/2005
• Issued: 02/26/2008
• Est. Priority Date: 06/23/2005
• Status: Expired due to Fees

• Current Assignee: Enerlab Incorporated
• Original Assignee: Enerlab Incorporated
• Inventors: Praskovskaya, Eleanor, Praskovsky, Alexander
• Primary Examiner(s): Sotomayor; John B.
• Application Number:
  US11/159,581
• Publication Number:
  US 20060290561A1
• Time in Patent Office: 978 Days
• Field of Search: 342/22, 342/27, 342/28, 342/59, 342/90, 342/179, 342194-196, 342/26.R, 342/26.D
• US Class Current: 342/195
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar

Abstract

A method and system is provided for obtaining data indicative of at least one characteristic of a continuous medium or at least one localized target located within a predetermined volume of space. The system includes a sensor configuration and a processing circuit. The sensor configuration includes a plurality of sensors for acquiring a plurality of signals from the continuous medium or the target(s). The plurality of sensors have centers spatially separated from each other in at least one spatial dimension. The processing circuit is configured for obtaining data indicative of the characteristic or characteristics of the medium or the target by calculating a plurality of powered weighted increments using the plurality of signals acquired by the sensor configuration and by using a plurality of models for relating the plurality of powered weighted increments to the characteristic or characteristics of the medium or the target. The selected characteristics of the medium or the target can be estimated with better accuracy and temporal and/or spatial resolution than is possible with prior art correlation function, spectra, and structure function-based methods and systems. In contrast to prior art methods and systems, the invention is not sensitive to signal contaminants with large temporal scale such as ground and sea clutter, and is not sensitive to low frequency external interference. The invention is capable of estimating various characteristics of the medium or target, for example, size, shape, visibility, speed, direction of the motion, and rates of changes of the above characteristics.

Claims

1. A system for obtaining data indicative of at least one characteristic of a continuous medium or at least one localized target located within a predetermined volume of space, which comprises:

a sensor configuration including a plurality of sensors for acquiring a plurality of signals from the continuous medium or the target, said plurality of sensors having centers spatially separated from each other in at least one spatial dimension; and

a processing circuit for obtaining said data indicative of said characteristic of the continuous medium or the target by calculating a plurality of powered weighted increments using said plurality of signals acquired by said sensor configuration and by relating said plurality of powered weighted increments to said characteristic of the continuous medium or the target using a plurality of models.

2. The system according to claim 1, wherein said plurality of sensors is configured for concurrently acquiring said plurality of signals from the continuous medium or the target.

3. The system according to claim 2, wherein each one of said plurality of sensors is positioned at a predetermined location inside the predetermined volume of space.

4. The system according to claim 2, wherein:

said plurality of sensors is positioned outside the predetermined volume of space; and

said plurality of signals acquired by said plurality of sensors is generated by the continuous medium or the target.

5. The system according to claim 2, wherein:

said plurality of sensors is positioned outside the predetermined volume of space; and

said plurality of signals acquired by said plurality of sensors is caused by predetermined radiation that is generated and propagated through the predetermined volume of space to induce backscatter from the continuous medium or the target.

6. The system according to claim 1, wherein said processing circuit is configured for increasing an amount of information extractable from said plurality of signals by modifying said plurality of signals, and subsequently obtaining said data indicative of said characteristic of the continuous medium or the target.

7. The system according to claim 6, wherein said processing circuit is configured for modifying said plurality of signals by performing at least one modification step selected from a group consisting of:

converting said plurality of signals from complex signals to real signals, removing noise from said plurality of signals, removing mean values from said plurality of signals, normalizing each one of said plurality of signals with a standard deviation of the respective one of said plurality of signals, and generating virtual sensors using combinations of said plurality of signals.

8. The system according to claim 1, wherein said processing circuit is configured for calculating said plurality of powered weighted increments for one or more specified orders, specified pairs of signals from said plurality of said sensors, and specified combinations of weights.

9. The system according to claim 1, wherein said processing circuit is configured for relating said plurality of powered weighted increments to said characteristic of the medium or target by:

fitting said plurality of powered weighted increments to a plurality of predetermined models, estimating a plurality of adjustable parameters in said plurality of predetermined models, and relating said plurality of adjustable parameters to said characteristic of the continuous medium or the target.

10. The system according to claim 9, wherein at least one of said plurality of predetermined models is formed as a decomposition into a Taylor series.

11. The system according to claim 9, wherein each one of said plurality of predetermined models is constructed from at least one model selected from a group consisting of an analytically derived operational equation formed as a decomposition into a polynomial function over a selected parameter, a tabulated function obtained using a numerical simulation, and a tabulated function obtained using a physical experiment.

12. The system according to claim 1, wherein said processing circuit is configured for increasing an accuracy of said data indicative of said characteristic of the medium or the target by analyzing multiple estimates of said data indicative of said characteristic of the continuous medium or the target.

13. The system according to claim 1, further comprising an output circuit for outputting said data indicative of said characteristic of the continuous medium or the target.

14. A method for obtaining data indicative of at least one characteristic of a continuous medium or at least one localized target located within a predetermined volume of space, which comprises:

using a sensor configuration having a plurality of sensors with centers spatially separated from each other in at least one spatial dimension to acquire a plurality of signals from the continuous medium or the target; and

obtaining the data indicative of the characteristic of the continuous medium or the target by calculating a plurality of powered weighted increments using the plurality of signals acquired by the plurality of sensors and by relating the plurality of powered weighted increments to the characteristic of the medium or the target using a plurality of models.

15. The method according to claim 14, which comprises concurrently acquiring the plurality of signals from the continuous medium or the target with the plurality of sensors.

16. The method according to claim 14, which comprises positioning each one of the plurality of sensors at a predetermined location inside the predetermined volume of space.

17. The method according to claim 14, which comprises positioning each one of the plurality of sensors at a predetermined location outside the predetermined volume of space;

the plurality of signals acquired by the plurality of sensors being generated by the continuous medium or the target.

18. The method according to claim 14, which comprises:

positioning each one of the plurality of sensors at a predetermined location outside the predetermined volume of space; and

generating and propagating predetermined radiation through the predetermined volume of space to induce backscatter from the continuous medium or the target in a manner enabling the plurality of signals to be acquired by the plurality of sensors.

19. The method according to claim 14, which comprises:

increasing an amount of information extractable from the plurality of signals by modifying the plurality of signals; and

subsequently performing the step of obtaining the data indicative of the characteristic of the continuous medium or the target.

20. The method according to claim 14, which comprises:

increasing an amount of information extractable from the plurality of signals by performing at least one modification step selected from a group consisting of;

converting the plurality of signals from complex signals to real signals, removing noise from the plurality of signals, removing mean values from the plurality of signals, normalizing each one of the plurality of signals with a standard deviation of the respective one of the plurality of signals, and generating virtual sensors using combinations of the plurality of signals; and

subsequently performing the step of obtaining the data indicative of the characteristic of the continuous medium or the target.

21. The method according to claim 14, which comprises calculating the plurality of powered weighted increments for one or more specified orders, specified pairs of signals from the plurality of the sensors, and specified combinations of weights.

22. The method according to claim 14, which comprises relating the plurality of powered weighted increments to the characteristic of the medium or target by:

fitting the plurality of powered weighted increments to a plurality of predetermined models, estimating a plurality of adjustable parameters in the plurality of predetermined models, and relating the plurality of adjustable parameters to the characteristic of the continuous medium or the target.

23. The method according to claim 22, which comprises forming at least one of the plurality of predetermined models as a decomposition into a Taylor series.

24. The method according to claim 22, which comprises constructing each one of the plurality of predetermined models from at least one model selected from a group consisting of:

an analytically derived operational equation formed as a decomposition into a polynomial function over a selected parameter, a tabulated function obtained using a numerical simulation, and a tabulated function obtained using a physical experiment.

25. The method according to claim 14, which comprises increasing an accuracy of the data indicative of the characteristic of the continuous medium or the target by analyzing multiple estimates of the data indicative of the characteristic of the continuous medium or the target.

26. The method according to claim 14, which comprises outputting the data indicative of the characteristic of the continuous medium or the target.