Method and apparatus for attenuating of a broadcasting received signal for achieving a better distance resolution in monitoring systems

• US 20050012656A1
• Filed: 07/16/2003
• Published: 01/20/2005
• Est. Priority Date: 07/16/2003
• Status: Active Grant

• Current Assignee: Attenti Electronic Monitoring Ltd.
• Original Assignee: Dmatek, Ltd.
• Inventors: Rusman, Lev, Gemer, Gil, Greitser, Guy, Reisman, Yoav, Zeeli, Dan, Galperin, Natan
• Granted Patent: US 6,992,581 B2
• Time in Patent Office: Days
• US Class Current: 342/118
• CPC Class Codes: G01S 11/06 using intensity measurements

Abstract

A receiving unit and method for determining the distance of an object from a receiving unit in a monitoring system, the receiving unit receives transmitted signals, the receiving unit comprises an attenuating unit for attenuating the transmitted signals by a controlled factor; a receiver for receiving and processing the transmitted signals into readable data; a microcontroller for controlling the operation of the local monitoring unit; and an electronic circuitry for calculating the received strength signal indication, whereby the distance of an object from the receiving unit can be determined.

Claims

1. A receiving unit associated with at least one local monitoring unit for use in a monitoring system, the receiving unit receives signals transmitted from at least one transmitting tag, the receiving unit comprising:

an attenuating unit (110) for attenuating the transmitted signals by a controlled factor;

a receiver (120) for receiving and processing the transmitted signals into readable data;

a microcontroller (130) for determining the distance between the at least one transmitting tags and the receiving unit; and

an electronic circuitry (150) for calculating the received strength signal indication.

2. The receiving unit of claim 1 further comprising an antenna (100) for receiving the transmitted signal by the at least one transmitting tag.

3. The receiving unit of claim 1 further comprising an analog to digital converter (140) for converting the transmitted signals into digital signals.

4. The receiving unit of claim 1 wherein the transmitted signals are radio frequency signals.

5. A method for determining the distance of an at least one transmitting tags from a receiving unit, the method comprising the steps of:

waiting (210) for a signal to be received from an at least one transmitting tag;

receiving (220) the received signal, the received signal passes to a microcontroller for processing;

measuring (230) the received signal and calculating the received strength signal indication of the received signal;

If the received strength signal indication is stronger than a threshold level (240) the microcontroller is updated (241) and the attenuation is increased (step 242).

6. The method of claim 5 further comprising the steps of:

if the received signal strength indication is smaller than the threshold level (240), the microcontroller is queried to obtain a current attenuation factor value (243) and a distance between the receiver and the at least one transmitting tags is calculated (250).

7. The method of claim 5 wherein the receiver is a radio frequency receiver.

8. The method of claim 5 wherein the threshold level is pre calculated based on the receiver parameters.

9. The method of claim 6 wherein the calculation is performed using a lookup table.

10. The method of claim 5 wherein the at least one transmitting tag is worn by a monitored person.

11. The method of claim 5 wherein the at least one transmitting tag is worn by a monitored animal.

12. The method of claim 5 wherein the at least one transmitting tag is a securely device attached by a fixed or mobile object.