System and method for detecting objects and communicating information

• US 20060145853A1
• Filed: 12/22/2004
• Published: 07/06/2006
• Est. Priority Date: 12/22/2004
• Status: Abandoned Application

• Current Assignee: Time Domain Corporation (Humatics Corporation)
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James L., Fullerton, Larry W., Cowie, Ivan A.
• Application Number:
  US11/021,753
• Publication Number:
  US 20060145853A1
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/756 using a signal generator for modifying the reflectivity of the reflector G01S13/758 takes precedence
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G06K 7/10306 ultra wide band

Abstract

A system and method for locating objects and/or receiving data associated with an object. An antenna or similar device that can intercept or modify RF energy is caused to vary its properties in accordance with a predefined time sequence pattern that is associated with the object. The antenna device is located proximate to the object to be located. To locate the object, a wide band radar device is utilized to transmit a probe signal and receive and analyze the return signal to identify the predefined pattern and determine the range to the antenna and thus determine the range to the associated object. The time sequence pattern is optionally modulated by a data stream to convey data associated with the object.

Claims

1. A system for detecting an object, said system comprising:

(1) an ultra wideband transmitter for transmitting an ultra wideband probe signal;

(2) a tag device associated with the object and located proximal to the object, the tag device further comprising;

an antenna for receiving the ultra wideband probe signal;

a switch coupled to the antenna, said switch for modulating the probe signal received by the antenna and reflecting a portion of said signal back to the antenna; and

a controller coupled to the switch, said controller causing the switch to modulate the reflected signal in accordance with a time sequence pattern; and

(3) an ultra wideband receiver for receiving the modulated reflected signal and identifying the time sequence pattern.

2. The system of claim 1, wherein the transmitter is an impulse transmitter.

3. The system of claim 1, wherein the antenna is an elliptical dipole.

4. The system of claim 1, wherein the switch is one of the group:

a FET, a bipolar transistor, a PIN diode, a varactor diode, a variable capacitor, and a MEMS switch.

5. The system of claim 1, wherein the time sequence pattern includes a code pattern.

6. The system of claim 1, wherein the time sequence pattern includes a frequency modulated pattern.

7. The system of claim 1, wherein the modulation of the reflected signal is pulse position modulation.

8. The system of claim 1, further including a transmission line and a plurality of switches, each switch at a different delay along the transmission line, each said switch controlled in accordance with a protocol;

wherein the reflected signal is modulated with pulse position modulation.

9. The system of claim 1, wherein data is encoded on the time sequence pattern.

10. The system of claim 1, further including a plurality of objects, each of said objects having a tag device associated with said object;

wherein the modulated reflected signal from a first object is distinguished from the modulated reflected signal from a second object by range gating the modulated reflected signal from the first object.

11. A method for detecting an object comprising:

transmitting an ultra wideband signal toward an antenna;

modulating the impedance of a load connected to the antenna; and

receiving a reflected ultra wideband signal, said reflected ultra wideband signal being reflected from the load and having modulation resulting from the modulation of the impedance of the load; and

detecting the modulation of the reflected ultra wideband signal.

12. The method of claim 11, further comprising the step of:

determining the radar range to the antenna.

13. The method of claim 11, wherein the impedance is modulated in accordance with data;

the method further comprising the step of;

determining the data from the modulation.

14. The method of claim 13, wherein the modulation includes a code pattern.

15. The method of claim 14, wherein the code is one of a PN code, a Barker code, a Kassami code, and a Gold code.

16. The method of claim 13, wherein the modulation includes a frequency modulated signal.

17. The method of claim 13, wherein the modulation is analog modulation.

18. The method of claim 13, wherein the modulation is pulse position modulation.

19. The method of claim 13, wherein the detecting is performed by a dual channel IQ detector.

20. The method of claim 13, wherein the load is varied by one of a FET, a bipolar transistor, a PIN diode, a varactor diode, a variable capacitor, and a MEMS switch.