Information gathering using reflected satellite signals

• US 20060077094A1
• Filed: 07/22/2005
• Published: 04/13/2006
• Est. Priority Date: 07/26/2004
• Status: Active Grant

• Current Assignee: Drexel University
• Original Assignee: Drexel University
• Inventors: Eisenstein, Bruce A.
• Granted Patent: US 7,564,402 B2
• Time in Patent Office: Days
• US Class Current: 342/357.310
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems

Abstract

A method of using reflected satellite signals, such as GPS signals or high orbit satellite signals, to determine information including the steps of: receiving direct and reflected satellite signals from the same satellite at one or more receivers, comparing a power of said reflected satellite signal with a power of the direct satellite signal from the same satellite to obtain a ratio, comparing the ratio to at least one calibrated ratio obtained from calibration data; and determining information from a result of said step of comparing said ratios. The method is useful for the purpose of determining information about the presence or absence of an object, person or animal, the volume of motor vehicle or foot traffic, the aridity of land, monitoring an area for intruders, monitoring parking lots and enhancing security systems.

Claims

1. A method of using reflected satellite signals to determine information comprising the steps of:

receiving direct and reflected satellite signals from the same satellite at one or more receivers;

comparing a power of said reflected satellite signal with a power of the direct satellite signal from the same satellite to obtain a ratio;

comparing the ratio to at least one calibrated ratio obtained from calibration data; and

determining information from a result of said step of comparing said ratios.

2. The method of using reflected satellite signals as set forth in claim 1, wherein said step of comparing said reflected satellite signal with said direct satellite signal comprises the steps of:

determining a value for said reflected satellite signal;

determining a value for said direct satellite signal; and

comparing the determined value for said reflected satellite signal to the determined value for said direct satellite signal to obtain a ratio.

3. The method of using reflected satellite signals as set forth in claim 2, further comprising the step of adjusting the calibrated ratio using information obtained from one or more reflected satellite signals.

4. The method of using reflected satellite signals as set forth in claim 1, wherein said determined information is selected from the group consisting of:

traffic volume, aridity of land, a presence or absence of an object, person or animal, topographical features of land, and a number of objects, persons or animals.

5. The method of using reflected satellite signals as set forth in claim 2, further comprising the step of taking an action based on said determined information.

6. The method of using reflected satellite signals as set forth in claim 5, wherein said action is selected from the group consisting of:

providing a notification, activating an alarm, transmitting information, and activating a watering system.

7. The method of using reflected satellite signals as set forth in claim 2, further comprising the step of determining a Doppler shift for said reflected satellite signal.

8. The method of using reflected satellite signals as set forth in claim 7, wherein said system determines information about the speed of movement of an object, person or animal based on said Doppler shift.

9. The method of using reflected satellite signals as set forth in claim 2, further comprising the step of determining information about a phase of said reflected satellite signal.

10. The method of using reflected satellite signals as set forth in claim 1, wherein said reflected satellite signal and said direct satellite signal are from a GPS satellite.

11. A method of using reflected satellite signals to determine information comprising the steps of:

receiving reflected satellite signals from the same satellite at one or more receivers;

determining one or more of a power, a Doppler shift or a phase of said reflected satellite signal;

comparing one or more of the determined power, Doppler shift or phase of said reflected satellite signal to at least one calibrated value of a power, Doppler shift or phase obtained from calibration data; and

determining information from a result of said step of comparing said determined power, Doppler shift or phase.

12. The method of using reflected satellite signals as set forth in claim 11, wherein said determined information is selected from the group consisting of:

traffic volume, aridity of land, a presence or absence of an object, person or animal, topographical features of land, and a number of objects, persons or animals.

13. The method of using reflected satellite signals as set forth in claim 11, further comprising the step of taking an action based on said determined information.

14. The method of using reflected satellite signals as set forth in claim 13, wherein said action is selected from the group consisting of:

providing a notification, activating an alarm, transmitting information, and activating a watering system.

15. The method of using reflected satellite signals as set forth in claim 11, further comprising the step of modifying said calibration data using data obtained from one or more of said reflected satellite signals.

16. The method as claimed in claim 15, wherein said step of modifying said calibration data comprises the steps of obtaining information from said data obtained from one or more of said reflected satellite signals, processing said data, and adjusting a result determinative value obtained from said calibration data based on said information obtained from one or more of said reflected satellite signals.

17. The method as claimed in claim 11, wherein said method is employed to determine the presence or absence of an object, person or animal.

18. The method of using reflected satellite signals as set forth in claim 11, wherein said reflected satellite signal is from a high orbit satellite.

19. The method of using reflected satellite signals as set forth in claim 11, wherein said reflected satellite signal is from a low orbit satellite.

20. The method of using reflected satellite signals as set forth in claim 11, wherein said reflected satellite signal is from a middle orbit satellite.