Method and system for mobile network aided positioning

1. A method for fixing a position of a user apparatus with the assistance of a cellular communications network comprising:

starting a fixing session and, within said fixing session:

determining, at network equipment, a size of a first portion of a snapshot of a signal of a positioning system depending on the quality of said signal at the user apparatus, said snapshot being capable of enabling the fixing of the position;

communicating to the user apparatus said size of the first portion;

receiving, at network equipment, from the user apparatus via a network connection the first portion of said snapshot; and

fixing at the network equipment the position of the user apparatus on the basis of said snapshot.

2. The method of claim 1 , wherein determining the size of the first portion of the snapshot comprises identifying the environment of the user apparatus and determining the size of the snapshot depending on said identified environment.

3. The method of claim 1 , further comprising, at the network equipment, sending to the user apparatus a request for a second portion of said snapshot and receiving said second portion of said snapshot.

4. The method of claim 3 , wherein a size of the second portion is predetermined.

5. The method of claim 4 , wherein the size of the second portion is at least two times the size of the first portion.

6. The method of claim 4 , further comprising sending to the user apparatus a request for a third portion of said snapshot having the respective size predetermined and receiving said third portion of said snapshot.

7. The method of claim 3 , wherein determining the size of said snapshot comprises determining, at the network equipment, a size of the second portion and further comprising communicating to the user apparatus said size of the second portion before receiving the second portion of said snapshot.

8. The method of claim 1 , wherein determining the size of the first portion of said snapshot comprises receiving measurement data related to at least a signal of a mobile network and determining said size of the first portion of said snapshot on the basis of said data.

9. The method of claim 1 , wherein determining the size of the first portion of said snapshot comprises determining the length of time of the signal of the positioning system corresponding to said snapshot.

10. The method of claim 1 , wherein the network connection is a mobile network connection.

11. The method of claim 1 , wherein the positioning system is a satellite-based positioning system.

12. The method of claim 1 , wherein starting the fixing session comprises receiving at the network equipment from the user apparatus a request for fixing the position.

13. The method of claim 1 , further comprising sending the fixed position from the network equipment to the user apparatus through said network connection.

14. A system for providing a service of positioning of a mobile user apparatus with the assistance of a cellular communications network, comprising:

network equipment;

a mobile user apparatus capable of establishing a mobile network connection with the network equipment, the mobile user apparatus comprising a receiver capable of digitally sampling a signal of a positioning system, the network equipment and the mobile user apparatus being capable of cooperating so as to implement the method of:

determining, at network equipment, a size of a first portion of a snapshot of a signal of a positioning system depending on the quality of said signal at the user apparatus, said snapshot being capable of enabling the fixing of the position;

communicating to the user apparatus said size of the first portion;

receiving, at network equipment, from the user apparatus via a network connection the first portion of said snapshot; and

fixing at the network equipment the position of the user apparatus on the basis of said snapshot.

15. A service for providing a user of a user apparatus of a fix of the position of the user apparatus with the assistance of a cellular communications network, wherein said fix of the position is based on the method of:

determining, at network equipment, a size of a first portion of a snapshot of a signal of a positioning system depending on the quality of said signal at the user apparatus, said snapshot being capable of enabling the fixing of the position;

communicating to the user apparatus said size of the first portion;

receiving, at network equipment, from the user apparatus via a network connection the first portion of said snapshot; and

fixing at the network equipment the position of the user apparatus on the basis of said snapshot.