User positioning technique for multi-platform communication system

• US 6,920,309 B1
• Filed: 06/06/2000
• Issued: 07/19/2005
• Est. Priority Date: 03/18/1999
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Chang, Donald C. D., Hagen, Frank A., Yung, Kar
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Miller, Brandon J
• Application Number:
  US09/587,759
• Time in Patent Office: 1,869 Days
• Field of Search: 455/456, 455/13.1, 455/13.2, 455/12.1, 455/67.6, 455/502, 455/503, 455/430, 370/316, 370/326
• US Class Current: 455/13.1
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/18547 for geolocalisation of a station position fixing by direction or distance determination G01S5/00

Abstract

A mobile wireless communications system including a plurality of individual transponding nodes all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal associated with a remote user that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements. The central hub can determine the position of each of the remote users based on stored information derived from the synchronization of the various signals, and specifically relating to the timing, phase or frequency of the signals in both the forward and return link.

Claims

1. A method for determining user position, comprising:

providing a plurality of individual transponding nodes;

establishing a plurality of links from a central processing hub with at least one remote user through said plurality of individual transponding nodes;

processing, at said hub, a plurality of signals transmitted from said at least one remote user through said plurality of links, including assigning a same code to each of said plurality of links, such that the timing, phase, and frequency of signals in both the forward and return links with respect to said at least one remote user are synchronized for said plurality of individual transponding nodes; and

determining the range of said at least one remote user utilizing the timing.

2. The method of claim 1, further comprising:

providing additional information about the position of said at least one remote user based on the frequency.

3. The method of claim 2, further comprising:

assisting in determining the position of said at least one remote user based on the phase.

4. The method of claim 1, wherein the range is related to the user position by the following equation:

r_i²=(x−

x_pi)²+(y−

y_pi)²+(z−

z_pi)².

5. The method of claim 2, wherein the user position is further conditioned by the following equation:

r_ir_i=(x−

x_pi)(x−

x_pi)+(y−

y_pi)(y−

y_pi)+(z−

z_pi)(z−

z_pi).

6. The method of claim 3, wherein further user positioning information is provided based on the following equation:

phase≈

r_i mod τ

.

7. A mobile wireless communication system, comprising:

a plurality of individual transponding nodes;

a plurality of mobile terminals each associated with a respective remote user;

a central hub for establishing forward and return links with one or more of said plurality of mobile terminals, each through at least two of said plurality of individual transponding nodes and wherein each of said at least two of said plurality of individual transponding nodes can communicate with a respective one of said plurality of mobile terminals at the same frequency;

said central hub processing one or more signals received from said one or more of said plurality of mobile terminals and synchronizing one or more signals transmitted to said one or more of said plurality of mobile terminals such that an intended one of said one or more of said plurality of mobile terminals receives signals synchronously and in-phase;

whereby said central hub can determine the position of each one of said one or more of said plurality of mobile terminals based on information stored on said central hub regarding the timing, phase and/or frequency of signals in both the forward and return links.

8. The system of claim 7, wherein said central hub uses information about the timing of signals received from said one or more of said plurality of mobile terminals to assist in determining the position of said one or more of said plurality of mobile terminals.

9. The system of claim 8, wherein said user position information is determined according to the following equation:

r_i²=(x−

x_pi)²+(y−

y_pi)²+(z−

z_pi)².

10. The system of claim 7, wherein said central hub uses information about the frequency of signals received from said one or more of said plurality of mobile terminals to assist in determining the position of said one or more of said plurality of mobile terminals.

11. The system of claim 10, wherein said user position information is determined according to the following equation:

r_ir_i=(x−

x_pi)(x−

x_pi)+(y−

y_pi)(y−

y_pi)+(z−

z_pi)(z−

z_pi).

12. The system of claim 7, wherein said central hub uses information about the phase of signals received from said one or more of said plurality of mobile terminals to assist in determining the position of said one or more of said plurality of mobile terminals.

13. The system of claim 12, wherein said user position information is determined according to the following equation:

phase≈

r_i mod τ

.

14. The system of claim 7, wherein said central hub uses information about the timing, phase and frequency of signals received from said one or more of said plurality of mobile terminals to assist in determining the position of said one or more of said plurality of mobile terminals.

15. A method for determining the position of a mobile user terminal in a wireless communication system, comprising:

providing a plurality of mobile user terminals;

establishing links between each of said plurality of mobile user terminals and a hub through a plurality of transponding nodes;

processing a plurality of signals from said plurality of mobile user terminals at said hub such that signals are delivered to at least one intended. mobile user terminal of said plurality of mobile terminals coherently and in-phase, and wherein said hub can transmit a plurality of signals at the same frequency to said at least one intended mobile user terminal through said plurality of transponding nodes; and

determining the position of said at least one intended mobile user terminal based on signals received from said at least one intended mobile user terminal and stored on said hub as timing, phase, and/or frequency information.

16. The method of claim 15, wherein said determining includes gathering information about the position of said at least one intended mobile user terminal based on frequency information.

17. The method of claim 15, wherein said determining includes gathering information about the position of said at least one intended mobile user terminal based on timing information.

18. The method of claim 15, wherein said determining includes gathering information about the position of said at least one intended mobile user terminal based on phase information.

19. The method of claim 15, wherein said determining includes gathering information about the position of said at least one intended mobile user terminal based on any combination of information from each of said timing, phase, and frequency.

20. The method of claim 15, wherein each of said plurality of transponding nodes is independently selected from one of the following system types:

a space-based system, a high altitude platform system, or a tower based cellular network.

21. A multi-platform communication system, comprising:

a hub for transmitting synchronized signals; and

a plurality of transponding nodes capable of receiving the synchronized signals from said hub and transmitting the synchronized signals to at least one intended user terminal such that the synchronized signals are received by said at least one intended user terminal synchronously and in-phase,

wherein said hub uses one or more of timing, phase and frequency information collected from one or more signals from said at least one intended user terminal to determine the position of said at least one intended user terminal and synchronize signals.

22. The system of claim 21, further comprising a plurality of user terminals, and

wherein said hub is capable of establishing links with said at least one intended user terminal and at least one of said plurality of user terminals, each through at least two of said plurality of transponding nodes, and

wherein each of said at least two of said plurality of transponding nodes can communicate with a respective one of said at least one intended user terminal and said at least one of said plurality of user terminals at the same frequency.

23. The system of claim 22, wherein said hub is capable of collecting information from one or more signals from said at least one intended user terminal and said at least one of said plurality of user terminals, for synchronizing signals such that said at least one intended user terminal receives the signals synchronously and in-phase.

24. The system of claim 23, wherein said hub synchronizes one or more of timing, phase and frequency of the synchronized signals.

25. The system of claim 21, wherein each one of said plurality of transponding nodes is selected from a group consisting of a space-based system, a high-altitude platform system and a tower-based cellular system.

26. A method of transmitting communication signals to multiple user terminals, comprising:

processing signals from multiple user terminals at a hub to obtain information for synchronization and determination of the positions of said multiple user terminals; and

using the information to transmit synchronized signals from said hub through a plurality of transponding nodes to at least one intended user terminal of said multiple user terminals such that the synchronized signals are received by said at least one intended user terminal synchronously and in-phase, and further comprising;

establishing forward and return links between said hub and said at least one intended user terminal and at least one other terminal of said multiple user terminals, each through at least two of said plurality of transponding nodes, and

transmitting from each of said at least two of said plurality of transponding nodes to a respective one of said at least one intended user terminal and said at least one other terminal at the same frequency.

27. A method of transmitting communication signals to multiple user terminals, comprising:

processing signals from multiple user terminals at a hub to obtain information for synchronization and determination of the positions of said multiple user terminals; and

using the information to transmit synchronized signals from said hub through a plurality of transponding nodes to at least one intended user terminal of said multiple user terminals such that the synchronized signals are received by said at least one intended user terminal synchronously and in-phase,

wherein the information obtained at said hub comprises timing, phase and frequency information, and wherein said hub synchronizes one or more of the timing, phase and frequency of signals transmitted to said at least one intended user terminal and said at least one other terminal in both a forward;

link and a return link.

28. The method of claim 27, wherein the synchronized signals have incorporated therein a timing delay in both the forward and return links.

29. The system of claim 27, wherein each one of said plurality of transponding nodes is selected from a group consisting of a space-based system, a high-altitude platform system and a tower-based cellular system.

30. A method for determining user position in a multi-transponder communication system, comprising:

collecting data from signals received from user terminals at a hub through a plurality of transponding nodes, and

determining at said hub, the positions of said user terminals using the collected data, wherein the data includes frequency, timing and/or phase data, and further comprising;

after determining the positions of said user terminals, synchronizing signals at said hub such that the synchronized signals when transmitted from said hub through at least two of said plurality of transponding nodes arrive at an intended one of said user terminals coherently and in-phase and arrive at a non-intended one of said user terminals out-of-phase.

31. The method of claim 30, wherein the step of synchronizing comprises use of a timing delay in the synchronized signals in both forward and return links between said hub and said intended one of said user terminals.

32. The method of claim 31, further comprising modifying the timing delay based on position of said intended one of said user terminals.

33. The method of claim 32, further comprising tracking the position of said intended one of said user terminals and suitably modifying the time delay of signals transmitted to and received from said intended one of said user terminals.

34. A method for communicating signals to multiple user terminals in a multi-transponder communication system, comprising:

collecting user position information, including timing, phase and frequency information, from signals received from said multiple user terminals at a hub;

determining, at said hub, the positions of said multiple user terminals using the collected user position information;

synchronizing signals for transmission through at least two transponding nodes to an intended one of said multiple user terminals using the collected user position information; and

transmitting synchronized signals to said at least two transponding nodes such that said at least two transponding nodes transmit the synchronized signals for arrival at said intended one of said multiple user terminals synchronously and in-phase.

35. The method of claim 34, wherein the step of synchronizing comprises use of a timing delay in the synchronized signals in both forward and return links.

36. The method of claim 35, further comprising tracking the position of said intended one of said multiple user terminals and suitably modifying the time delay of the synchronized signals transmitted to said intended one of said multiple user terminals.