System And Method For Determining The Location Of A Location Tracking Device

• US 20100035630A1
• Filed: 12/28/2006
• Published: 02/11/2010
• Est. Priority Date: 12/28/2006
• Status: Active Grant

• Current Assignee: Worldscout Corporation
• Original Assignee: Worldscout Corporation
• Inventors: Lazovic, Nenad, Bosnjakovic, Miroslav
• Granted Patent: US 8,121,609 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data

Abstract

A system and method for determining the location of a location tracking device employs a satellite based location determining infrastructure, such as the GPS system, and a wireless data communications network such as a cellular voice and/or data network such as GSM/GPRS. A location tracking device which cannot easily obtain valid ephemeris data, or the like, from the satellite based location determining infrastructure requests the necessary data from a data set stored at a tracking device hub or the like, via the wireless communications network. The tracking device hub determines an estimated position of the location tracking device and this estimated location is transmitted to the location tracking device, along with the appropriate required valid ephemeris data, or the like, to allow the location tracking device to determine its location. If the location tracking device is still unable to make a location determination from the satellite based location determining infrastructure, then the estimated location can be provided. The topography of the base stations, which is used to estimate the location of the location tracking device, is self-determined by a process executing in the system and can include base stations from networks operated by different network operators.

Claims

1. A method for determining the location of a location tracking device which employs a satellite-based positioning system, when the location tracking device does not have at least some of the data required from the satellite-based positioning system to determine a location, comprising the steps of:

(i) the location tracking device sending a request to a remote data device, via a wireless data communication link provided by a radio data communications network, the request including a set of identifiers and respective time delay data for a selected number of wireless network base stations which the location tracking device can receive signals from;

(ii) the remote data device receiving, via the wireless data communication link, the request from the location tracking device and processing the set of identifiers and time delay data against a determined topography of radio data communication network base stations to determine an estimated location of the wireless location tracking device;

(iii) the remote data device selecting, based upon the estimated location, a set of appropriate data for the location tracking device to determine a location with the satellite-based positioning system, and transmitting to the location tracking device, via the wireless data communications link, the estimated location and the set of appropriate data;

(iv) the location tracking device receiving, via the wireless data communications link, and employing the estimated location and the set of appropriate data to receive appropriate signals from the satellite-based positioning system to determine the location of the location tracking device.

2. The method of claim 1 wherein, if at step (iv) the location tracking device cannot determine its location from the satellite-based positioning system, the estimated location created at step (ii) is used as the location of the location tracking device.

3. The method of claim 1 wherein the satellite-based positioning system is the Global Positioning System.

4. The method of claim 3 wherein the set of appropriate data includes ephemeris data for a set of GPS satellites which can be visible to the location tracking device.

5. The method of claim 4 wherein the set of appropriate data further includes an indication of the current time.

6. The method of claim 1 wherein the radio data communications network is a GSM network.

7. The method of claim 1 wherein the radio data communications network is a GSM/GPRS network.

8. The method of claim 1 wherein the time delay data is data transmitted by the wireless network base stations which can be used to estimate the distance between the location tracking device and a radio data communication network base station.

9. The method of claim 6 wherein the time delay data is the time delay data transmitted by the GSM base stations.

10. The method of claim 1 wherein the determined topography is created by receiving location information from at least one location tracking device, the location information including the location of the location tracking device as determined from signals from the satellite-based positioning system and a set of identifiers and respective time delay data for a selected number of radio data communication network base stations which the location tracking device can receive signals from, the topography being determined by processing this information to determine the locations of the radio data communication network base stations.

11. The method of claim 10 wherein the radio data communication network base stations can comprise base stations from radio data communication networks operated by different network operators.

12. The method of claim 10 wherein the radio data communication network base stations can comprise base stations from radio data communication networks employing different multiplexing techniques.

13. The method of claim 10 wherein the determined topography is updated on an ongoing basis.

14. The method of claim 4 wherein the ephemeris data is received by a location tracking device and is forwarded to the remote data device at intervals.

15. A system for determining the location of a location tracking device which employs a satellite-based positioning system, the system comprising:

a plurality of location tracking devices, each location tracking device including a receiver for a satellite-based positioning system and a transceiver for a radio data communications network; and

a tracking device hub, the hub including;

a data connection to the radio data communication network to allow communication between the tracking device hub and each of the plurality of location tracking devices;

storage of data from the satellite-based positioning system, the stored data being useful to the location tracking devices to determine their locations from the satellite-based location system;

a determined topography of base stations of the radio data communication network; and

processing means responsive to time delay data received from a location tracking device to determine from the developed topography an estimated position for the location tracking device.

16. A method of determining a topography of the base stations for at least one radio data communications network, comprising the steps of:

(i) deploying at least one location tracking device within a geographic area served by the at least one radio data communications network;

(ii) receiving, at intervals, transmissions from the at least one location tracking device, the transmissions including the present location of the location tracking device as determined from a satellite-based positioning system and a set of identifiers for at least one base station of the radio data communications network from which the location tracking device can receive signals and time delay data representing the distance of the location tracking device from each of the at least one base station;

(iii) processing the received location, identifiers and time delay data to determine the distance of each of the identified at least one base stations from the determined location of the tracking device;

(iv) compiling a topography of the identified base stations indicating their respective locations.

17. The method of claim 16 wherein the base stations are from radio data communications networks operated by different service providers.

18. The method of claim 17 wherein steps (ii) through (iv) are repeated, at intervals, to update the topography.

19. The method of claim 16 further comprising the steps of:

(a) receiving, from a device operable to receive data from two or more base stations of the radio data communications network, a set of identifiers for the at least two base stations of the radio data communications network and time delay data representing the distance of the device from each of the at least two base station; and

(b) processing the received time delay data and the compiled topography to estimate the location of the device.

20. The method of claim 19 wherein the device is a cellular telephone.

21. A location tracking device, comprising:

a receiver operable to receive and process satellite signals from a satellite-based positioning system;

a data transceiver operable to transmit and receive data through a radio data communications network;

a microcontroller operable to execute at least one program to control operation of the device such that the device can report, via the radio data communications network, a location determined by the receiver and a set of identifiers and respective time delay data for a selected number of radio data communications network base stations which the data transceiver of the location tracking device can receive signals from.