System and method for tracking the location of multiple mobile radio transceiver units

• US 7,340,260 B2
• Filed: 10/09/2003
• Issued: 03/04/2008
• Est. Priority Date: 10/09/2002
• Status: Expired due to Term

• Current Assignee: MDF Holdings Incorporated
• Original Assignee: MDF Holdings Incorporated
• Inventors: McAlexander, Joseph C.
• Primary Examiner(s): Nguyen; David Q
• Application Number:
  US10/683,571
• Publication Number:
  US 20050054351A1
• Time in Patent Office: 1,608 Days
• Field of Search: 455/456.1, 455/423, 455/457, 455/463, 701/200, 201/202, 201/213
• US Class Current: 455/456.1
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 19/51 Relative positioning
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems

Abstract

An object locating system (100), the system (100) comprising at least first and second mobile devices (120, 130) associated by a relationship defined at least in part by a threshold. The at least first and second mobile devices are operable to be monitored by a communication network as one mobile device (120) or as separate mobile devices (120, 130) as a function of the relationship relative to the threshold.

Claims

1. A method, comprising:

determining, at a first mobile device capable of operating within a tracking system, a position of the first mobile device;

transmitting, from the first mobile device to a central monitoring system associated with the tracking system, first position information associated with the first mobile device;

relaying, from the first mobile device to the central monitoring system, second position information associated with a second mobile device; and

switching the first mobile device from being a primary mobile unit to a secondary mobile unit such that the first mobile device transmits the first position information to at least one of the second mobile device and a third mobile device for relaying to the central monitoring system, and wherein when the first mobile device is a secondary mobile unit the first mobile device communicates directly only with the at least one of the second mobile device and the third mobile device.

2. The method of claim 1, wherein the relaying of the second position information to the central monitoring system by the first mobile device occurs when the second mobile device is within a threshold distance of the first mobile device.

3. The method of claim 2, wherein the second mobile device is capable of transmitting the second position information directly to the central monitoring system when the second mobile device is not within the threshold distance of the first mobile device.

4. The method of claim 1, further comprising:

transmitting, from the first mobile device to the central monitoring system, a beacon signal only when the first mobile device cannot determine its location.

5. A tracking system, comprising:

a central monitoring system; and

a first mobile device capable of;

determining a position of the first mobile device;

transmitting to the central monitoring system first position information associated with the first mobile device;

relaying to the central monitoring system second position information associated with a second mobile device; and

switching the first mobile device from being a primary mobile unit to a secondary mobile unit such that the first mobile device transmits the first position information to at least one of the second mobile device and a third mobile device for relaying to the central monitoring system, and wherein when the first mobile device is a secondary mobile unit the first mobile device communicates directly only with the at least one of the second mobile device and the third mobile device.

6. The tracking system of claim 5, wherein the first mobile device is capable of relaying the second position information to the central monitoring system when the second mobile device is within a threshold distance of the first mobile device.

7. The tracking system of claim 6, wherein the second mobile device is capable of transmitting the second position information directly to the central monitoring system when the second mobile device is not within the threshold distance of the first mobile device.

8. The tracking system of claim 6, wherein a value of the threshold distance is static.

9. The tracking system of claim 6, wherein a value of the threshold distance is dynamic.

10. The tracking system of claim 5, wherein at least one of the first and second mobile devices comprises a Global Positioning System (GPS) unit.

11. The tracking system of claim 5, wherein at least one of the first and second mobile devices comprises a transceiver capable of receiving signals from an RF transponder.

12. The tracking system of claim 5, wherein the central monitoring system is capable of monitoring one or more positions of at least one of the first and second mobile devices while the at least one of the first and second mobile devices is within a defined geographical boundary.

13. The tracking system of claim 5, wherein the central monitoring system comprises a first base station and a second base station each capable of receiving a beacon signal from the first mobile device.

14. The tracking system of claim 13, wherein the central monitoring system is capable of determining the position of the first mobile device using a triangulation algorithm that uses the beacon signal received from the first mobile device by the first base station and the second base station.

15. A mobile device, comprising:

a position determining unit capable of determining a position of the first mobile device; and

at least one transceiver capable of;

transmitting, to a central monitoring system, first position information associated with the first mobile device;

relaying to the central monitoring system second position information associated with a second mobile device; and

after switching from a primary mobile unit to a secondary mobile unit, the first mobile device transmitting the first position information to at least one of the second mobile device and a third mobile device for relaying to the central monitoring system, and wherein when the first mobile device is a secondary mobile unit the first mobile device communicates directly only with the at least one of the second mobile device and the third mobile device.

16. The mobile device of claim 15, wherein the at least one transceiver is capable of relaying the second position information to the central monitoring system when the second mobile device is within a threshold distance of the first mobile device.

17. The mobile device of claim 16, wherein the second mobile device is capable of transmitting the second position information directly to the central monitoring system when the second mobile device is not within the threshold distance of the first mobile device.

18. The mobile device of claim 15, wherein the position determining unit comprises a Global Positioning System (GPS) unit.

19. The mobile device of claim 15, wherein the position determining unit comprises a transceiver capable of receiving signals from an RF transponder.

20. The mobile device of claim 19, wherein the at least one transceiver is capable of transmitting identification information associated with the RF transponder to the central monitoring system.

21. The mobile device of claim 15, wherein the at least one transceiver is capable of transmitting a beacon signal to a plurality of base stations associated with the central monitoring system.