Location determination system and method therefor

• US 6,972,719 B1
• Filed: 09/30/2004
• Issued: 12/06/2005
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Swope, Charles B., Rapps, Jason A., Tealdi, Daniel A., Sanchez, Julio A.
• Primary Examiner(s): Phan, Dao
• Application Number:
  US10/954,431
• Time in Patent Office: 432 Days
• Field of Search: 342/357.02, 342/357.06, 342/357.07, 342/450, 342/453, 342/417, 701/207, 701/213, 701/215
• US Class Current: 342/450
• 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 5/02216 Timing or synchronisation of the receivers
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A location determination system (100) utilizes a low accuracy timing infrastructure (106) to synchronize a personal tracking device (120) having high accuracy timing location determination devices integrated therein. The PTD (120) includes a radio frequency (RF) location unit (102) and integrated sensors, such as altimeter (132), GPS receiver (134) and inertial navigation unit (IMU) (136). The RF location unit (102) receives a synchronization command from the low accuracy timing infrastructure (106) and provides timing data representing range information in response thereto. The range information is used by the high accuracy timing infrastructure (180) to compute updated X, Y, Z coordinates of the PTD (120).

Claims

1. A personal tracking device (PTD) for use in a location determination system, comprising:

a controller;

a radio frequency (RF) location unit and a plurality of location sensors coupled to the controller; and

the RF location unit receiving a synchronization command from a low accuracy timing infrastructure and transmitting timing data representing ranging information to a high accuracy timing infrastructure in response thereto.

2. A personal tracking device for use in a location determination system as described in claim 1, wherein the ranging information is used by the high accuracy timing infrastructure to compute updated X, Y, Z coordinates of the PTD.

3. A personal tracking device for use in a location determination system as described in claim 1, wherein the plurality of integrated location sensors provide location data to the low accuracy timing infrastructure, and wherein the updated X, Y, Z coordinates and the location data provide an updated location determination of the PTD.

4. A personal tracking device for use in a location determination system as described in claim 1, wherein a link couples the high accuracy timing infrastructure to the low accuracy timing infrastructure.

5. The location determination apparatus of claim 4, wherein the synchronization command originates from the high accuracy timing infrastructure and is transmitted to the low accuracy timing infrastructure via the link, the low accuracy timing infrastructure then transmitting the synchronization command to the RF location unit, the RF location unit transmitting the timing data to the high accuracy timing infrastructure in response thereto.

6. A personal tracking device for use in a location determination system as described in claim 4, wherein the synchronization command originates from the low accuracy timing infrastructure along with a timing request, the synchronization command being transmitted to the RF location unit via an RF data channel while the timing request is sent to the high accuracy timing infrastructure via the link, the RF location unit transmitting the timing data to the high accuracy timing infrastructure in response to the synchronization command, and the high accuracy timing infrastructure anticipating the timing data based on the timing request.

7. A location determination system, comprising:

a portable tracking device (PTD);

a radio frequency (RF) location unit integrated into the portable tracking device;

a low accuracy timing infrastructure;

a high accuracy timing infrastructure linked to the low accuracy timing infrastructure; and

wherein the RF location unit transmits timing data to the high accuracy timing infrastructure in response to a synchronization command being received from the low accuracy timing infrastructure.

8. The location determination apparatus of claim 7, wherein the low accuracy timing infrastructure comprises a data infrastructure.

9. The location determination apparatus of claim 8, wherein the data infrastructure comprises a Public-Safety Communications Officials (APCO) infrastructure.

10. The location determination apparatus of claim 7, wherein the radio frequency (RF) location unit comprises a high accuracy timing location unit.

11. The location determination apparatus of claim 10, wherein the PTD further includes a plurality of location sensors providing location data to the low accuracy timing infrastructure.

12. The location determination apparatus of claim 11, wherein the plurality of location sensors includes:

an altimeter, a GPS receiver, and inertial navigation unit (IMU).

13. The location determination apparatus of claim 12, wherein the location data includes motion dynamics, navigation state vectors and location of the user, the location data being transferred to the low accuracy timing infrastructure via an RF data channel.

14. The location determination system of claim 7, wherein the synchronization command originates from the high accuracy timing infrastructure and is sent to the low accuracy timing infrastructure via the link and then proceeds from the low accuracy timing infrastructure to the RF location unit.

15. The location determination system of claim 7, wherein the synchronization command originates from the low accuracy timing infrastructure in conjunction with a timing request, the synchronization command being sent from the low accuracy timing infrastructure to the RF location unit via a radio frequency (RF) data channel while the timing request is sent from the low accuracy timing infrastructure to the high accuracy timing infrastructure over the link.

16. A method for updating location in a location determination system comprising the steps of:

providing a link between a low accuracy timing infrastructure and a high accuracy timing infrastructure;

providing a personal tracking device (PTD) having a radio frequency (RF) location unit integrated therein;

sending a synchronization command via the link to the RF location unit;

transmitting timing data representing ranging from the RF location unit to the high accuracy timing infrastructure; and

determining X, Y, Z coordinates of the PTD at the high accuracy timing infrastructure.

17. The method of claim 16, wherein the step of sending the synchronization command comprises the steps of:

sending the synchronization command from the high accuracy timing infrastructure via the link to the low accuracy timing infrastructure; and

sending the synchronization command to the RF location unit.

18. The method of claim 16 wherein the step of sending the synchronization command comprises the steps of:

sending the synchronization command from the low accuracy timing infrastructure to the RF location unit via an RF data channel; and

simultaneously sending a timing request from the low accuracy timing infrastructure to the high accuracy timing infrastructure via the link.

19. A method for updating location in a location determination system comprising the steps of:

providing a personal tracking device (PTD) having RF location tracking capability and other integrated location tracking technologies, an RF location infrastructure including a location server, and a Public-Safety Communications Officials (APCO) infrastructure operatively coupled to the RF location infrastructure;

communicating from the APCO infrastructure to the PTD via an RF data channel, to set up a transmission at a specified time in the future;

once the specified time has elapsed, transmitting an RF signal from the PTD to the RF location infrastructure, and at that same time, the PTD transmitting location data to the APCO infrastructure obtained from the other integrated location tracking technologies;

measuring the range from the PTD to the RF location infrastructure based on the RF signal;

repeating the step of measuring the range to provide a predetermined number of measured ranges;

computing, at the location server, an X, Y, Z location of the PTD based on the measured ranges; and

updating, at the location server, a location correction of the PTD based on the X, Y, Z coordinates and the location data obtained from the other integrated location tracking technologies.

20. The method of claim 19, wherein the specified time in the future is determined by the location server and communicated to the APCO infrastructure.

21. The method of claim 19, wherein the specified time in the future is determined by the APCO infrastructure, and the step of communicating further comprises the step of communicating from the APCO infrastructure to the location server that the location server will receive a transmission from the PTD at the specified time in the future.

22. The method of claim 19, wherein the RF location infrastructure comprises direct sequence spread spectrum (DSSS) infrastructure.

23. A location determination system, comprising:

a portable tracking device (PTD) having a plurality of tracking sensors integrated therein along with a radio frequency (RF) location unit;

a low accuracy timing infrastructure for receiving location data from the plurality of tracking sensors and for providing a synchronization command to the RF location unit; and

a high accuracy timing infrastructure linked to the low accuracy timing infrastructure, the RF location unit providing timing data used to measure ranging information at the high accuracy timing infrastructure in response to the synchronization command, the ranging information and location data are used to determine an updated location of the PTD.

24. The location determination system of claim 23, wherein the synchronization command originates from the high accuracy timing infrastructure.

25. The location determination system of claim 23, wherein the synchronization command originates from the low accuracy timing infrastructure.

26. The location determination system of claim 23, wherein the ranging information is used to compute updated X, Y, Z coordinates of the PTD.

27. The location determination system of claim 26, wherein the X, Y, Z coordinates are computed by a location server.

28. The location determination system of claim 23, wherein the low accuracy timing infrastructure comprises a Public-Safety Communications Officials (APCO) infrastructure.

29. The location determination system of claim 23, wherein the low accuracy timing infrastructure comprises a TETRA infrastructure.