Satellite based positioning of a wireless terminal

• US 20070258485A1
• Filed: 05/05/2006
• Published: 11/08/2007
• Est. Priority Date: 05/05/2006
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Kappi, Jani
• Granted Patent: US 7,907,087 B2
• Time in Patent Office: Days
• US Class Current: 370/468
• CPC Class Codes: G01S 19/072 Ionosphere corrections

Abstract

At least one set of values of parameters is determined, each set of values defining a respective troposphere model. The at least one determined set of parameter values is then assembled for transmission via a wireless communication network to a wireless terminal as assistance data for an assisted satellite based positioning of the wireless terminal.

Claims

1. A method comprising:

determining at least one set of values of parameters, each set of values defining a respective troposphere model; and

assembling said at least one determined set of parameter values for transmission via a wireless communication network to a wireless terminal as assistance data for an assisted satellite based positioning of said wireless terminal.

2. The method according to claim 1, wherein said parameters include at least one parameter for defining a time interval during which a troposphere model is valid.

3. The method according to claim 2, wherein said at least one parameter for defining a time interval comprises a parameter for defining a baseline time and a parameter for defining an interval length.

4. The method according to claim 1, wherein said parameters include at least one parameter for defining an area in which a troposphere model is valid.

5. The method according to claim 4, wherein said at least one parameter for defining an area comprises parameters for defining a central point of said area and a parameter for defining a size of said area.

6. The method according to claim 1, wherein said parameters include at least one zenith delay parameter for defining a tropospheric delay that would be experienced by a signal transmitted by a satellite and received by said wireless terminal, when said satellite was located at a zenith of said wireless terminal.

7. The method according to claim 6, wherein said at least one zenith delay parameter include a hydrostatic zenith delay parameter and a non-hydrostatic zenith delay parameter.

8. The method according to claim 6, wherein said parameters further include at least one parameter for specifying an adaptation rule for adapting a value of said at least one zenith delay parameter to a current altitude of said wireless terminal.

9. The method according to claim 8, wherein said at least one parameter for defining an adaptation of a value of said at least one zenith delay parameter to a current altitude h of said wireless terminal comprises parameters s₀, s₁, e_h and e_w for adapting a value of a hydrostatic zenith delay parameter Z_ho according to the equation:

Z_h(h)=s₀*h+s₁*h²+Z_h0*exp(−

e_h*h)

and for adapting a value of a non-hydrostatic zenith delay parameter Z_w0 according to the equation;

Z_w(h)=Z_w0*exp(−

e_w*h).

10. The method according to claim 6, wherein said parameters include parameters for at least one mapping function, which mapping function maps a value of said zenith delay parameter to a tropospheric delay that is experienced by a signal transmitted by a satellite and received by said wireless terminal, when said satellite is located at a current elevation angle to said wireless terminal.

11. The method according to claim 10, wherein said parameters for at least one mapping function include parameters for a mapping function mapping a hydrostatic zenith delay to a hydrostatic tropospheric delay and parameters for mapping a non-hydrostatic zenith delay to a non-hydrostatic tropospheric delay.

12. The method according to claim 10, wherein said parameters further include at least two gradient parameters for defining an azimuthally asymmetric effect of a tropospheric delay.

13. An apparatus comprising a processing component,

said processing component being configured to determine at least one set of values of parameters, each set of values defining a respective troposphere model;

and

said processing component being configured to assemble said at least one determined set of parameter values for transmission via a wireless communication network to a wireless terminal as assistance data for an assisted satellite based positioning of said wireless terminal.

14. The apparatus according to claim 13, wherein said processing component is configured to determine for a respective troposphere model at least one parameter value defining a time interval during which said troposphere model is valid and/or at least one parameter value defining an area in which said troposphere model is valid.

15. The apparatus according to claim 13, wherein said processing component is configured to determine for a respective troposphere model at least one zenith delay parameter value defining a tropospheric delay that would be experienced by a signal transmitted by a satellite and received by said wireless terminal, when said satellite was located at a zenith of said wireless terminal.

16. The apparatus according to claim 13, wherein said processing component is configured to determine for a respective troposphere model at least one parameter value specifying an adaptation rule for adapting a value of said at least one zenith delay parameter to a current altitude of said wireless terminal.

17. A network element of a wireless communication network, said network element comprising an apparatus according to claim 13 and a transmitting component configured to transmit at least one set of parameter values determined and assembled by said apparatus to a wireless terminal as assistance data for an assisted satellite based positioning of said wireless terminal.

18. A system comprising an apparatus according to claim 13 and a wireless terminal configured to receive at least one set of parameter values determined and assembled by said apparatus via a wireless communication network.

19. A software program product in which a software program code is stored in a readable medium, said software program code realizing the following when executed by a processor:

determining at least one set of values of parameters, each set of values defining a respective troposphere model; and

assembling said at least one determined set of parameter values for transmission via a wireless communication network to a wireless terminal as assistance data for an assisted satellite based positioning of said wireless terminal.

20. The software program product according to claim 19, wherein said parameters include at least one parameter for defining a time interval during which a troposphere model is valid and/or at least one parameter for defining an area in which a troposphere model is valid.

21. The software program product according to claim 19, wherein said parameters include at least one zenith delay parameter for defining a tropospheric delay that would be experienced by a signal transmitted by a satellite and received by said wireless terminal, when said satellite was located at a zenith of said wireless terminal.

22. The software program product according to claim 21, wherein said parameters further include at least one parameter for specifying an adaptation rule for adapting a value of said at least one zenith delay parameter to a current altitude of said wireless terminal.

23. An apparatus comprising:

means for determining at least one set of values of parameters, each set of values defining a respective troposphere model; and

means for assembling said at least one determined set of parameter values for transmission via a wireless communication network to a wireless terminal as assistance data for an assisted satellite based positioning of said wireless terminal.

24. A method comprising:

receiving at a wireless terminal via a wireless communication network at least one set of values of parameters, each set of values defining a respective troposphere model; and

using an available set of values as assistance data for an assisted satellite based positioning of said wireless terminal.

25. The method according to claim 24, further comprising selecting an available set of parameters for a troposphere model that is valid for a current time and for a current location of said wireless terminal as assistance data.

26. A wireless terminal arrangement comprising:

a mobile communication component configured to receive via a wireless communication network at least one set of values of parameters, each set of values defining a respective troposphere model; and

a positioning component configured to use an available set of values as assistance data for an assisted satellite based positioning of said wireless terminal arrangement.

27. The wireless terminal arrangement according to claim 26, wherein said positioning component is further configured to select an available set of parameters for a troposphere model that is valid for a current time and for a current location of said wireless terminal arrangement as assistance data.

28. A software program product in which a software program code is stored in a readable medium, said software program code realizing the following when executed by a processor:

receiving at a wireless terminal via a wireless communication network at least one set of values of parameters, each set of values defining a respective troposphere model; and

using an available set of values as assistance data for an assisted satellite based positioning of said wireless terminal.

29. An apparatus comprising:

means for receiving via a wireless communication network at least one set of values of parameters, each set of values defining a respective troposphere model; and

means for using an available set of values as assistance data for an assisted satellite based positioning of a wireless terminal.