Technique for Detecting Tracking Device Tampering

• US 20100090825A1
• Filed: 10/08/2009
• Published: 04/15/2010
• Est. Priority Date: 10/10/2008
• Status: Active Grant

• Current Assignee: Securus Technologies Incorporated (Securus Special Investments LLC)
• Original Assignee: Satellite Tracking of People LLC (Securus Special Investments LLC)
• Inventors: Freathy, Stephen Geoffrey
• Granted Patent: US 8,723,669 B2
• Time in Patent Office: Days
• US Class Current: 340/539.13
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article
• CPC Class Codes: G08B 21/22 responsive to presence or absence of persons

Abstract

A technique is disclosed for detecting the presence of a certain form of tampering with respect to the operation of a location tracking device. The tracking device is of the kind that receives signals from which the location of the tracking device is determined and the tampering that is detected is of the kind wherein signal shielding material is placed around the device and/or a signal jamming device is used. In accordance with one aspect of the present invention, the location tracking device includes a metal detector whose output is processed to provide a shielding alarm signal. In accordance with another aspect of the present invention, the gain provided by the AGC circuit in the GPS or other wireless signal receiver within the location tracking device is processed to form a shielding alarm signal. These alarm signals may be distinct so as to distinguish between the different forms of tampering. In addition, either one of these described aspects may be used alone or in combination with one another.

Claims

1. An improved location tracking device of the type having one or more receivers wherein each receiver receives associated signals at different times from which the device generates data representative of the location of the tracking device at such different times and wherein each receiver has associated automatic gain control circuitry for providing varying levels of gain, the improvement comprising at least one of the following (i) a metal detector disposed in location tracking device, said detector being tuned to detect metal provided it is within close proximity of the device and wherein said metal detector is used to generate an indication of a first form of tampering with the operation of the location tracking device and (ii) circuitry disposed in the location tracking device that analyzes the gain provided by said gain control circuitry and wherein said circuitry is used to generate an indication of a second form of tampering with the operation of the location tracking device.

2. The location tracking device of claim 1 wherein the first form of tampering involves use of signal shielding material and the second form involves use of a signal jamming device.

3. The location tracking device of claim 1 wherein the operation of the receivers is also examined and used along with the metal detector to generate said indication of the first form of tampering.

4. The location tracking device of claim 1 wherein the operation of the receivers is also examined and used along with the circuitry to generate said indication of the second form of tampering.

5. The location tracking device of claim 3 wherein a signal shielding alarm signal is generated if the indication of the first form of tampering occurs a predetermined number of times in a predetermined time interval.

6. The location tracking device of claim 5 further including a transmitter for transmitting the signal shielding alarm to a remote location.

7. The location tracking device of claim 5 wherein the location tracking device includes a memory to log the occurrence of the shielding alarm signal if the transmitter is unable to transmit this signal to the remote location.

8. The location tracking device of claim 6 wherein the transmitter repeatedly transmits the signal shielding alarm signal to the remote location until an acknowledgement signal is received from such location.

9. The location tracking device of claim 1 wherein the one or more receivers includes a UPS receiver.

10. The location tracking device of claim 9 wherein the circuitry which examines the gain control circuitry in each receiver compares the gain provide by such gain control circuitry to a predetermined threshold.

11. The location tracking device of claim 1 wherein the one or more receivers includes a wireless signal receiver.

12. The location tracking device of claim 11 wherein the circuitry which examines the gain control circuitry in each receiver compares the gain provide by such gain control circuitry to a predetermined threshold.

14. A method for countering attempts to thwart the operation of a location tracking device that generates data representative of its location at different times in response to signals received by a signal receiver, said method comprising the steps of:

providing a metal detector in the location tracking device configured to detect metal only if it is within close proximity of the device and providing an output signal indicating such detection and

generating a signal shielding alarm signal if the output signal meets prescribed criteria.

15. A method for countering attempts to thwart the operation of a location tracking device that generates data representative of the location of the location tracking device at different times in response to signals received by a receiver having associated gain control circuitry, said method comprising the steps of providing circuitry that analyzes the gain provided by said gain control circuitry to determine if a signal jamming device is interfering with the operation of that receiver and, if so, providing an output signal, and

generating a signal jamming alarm if the output signal meets prescribed criteria.