Method of improved positioning

1. A method of improved clustering for providing position determination assisting data in a cellular communication system, comprising:

providing a plurality of clusters of points, said points resulting from high-precision reference measurements, said points of each of said cluster having the same unique radio fingerprinting tag;

identifying a target cluster, said target cluster having a number of points less than a predetermined threshold; and

merging said target cluster with at least one selected adjacent cluster of said provided plurality of clusters to provide a merged cluster with an increased number of high-precision reference measurements.

2. The method of claim 1 , wherein said merging comprises:

removing a component of a tag of said target cluster in order to transform said tag to also include the tag of said at least one adjacent cluster; and

merging said target cluster and said at least one cluster into said merged cluster, said merged cluster being tagged with said transformed tag.

3. The method of claim 1 , wherein said merging comprises forming the union of said target cluster and said at least one adjacent cluster to form a merged cluster with an increased geographical extension.

4. The method of claim 1 , further comprising selecting said at least one selected adjacent cluster by ordering cell-IDs of said plurality of clusters based on their geographical position.

5. The method of claim 4 , further comprising selecting said at least one selected adjacent cluster by calculating center of gravities of all said clusters, and searching for clusters with center of gravities within a predetermined geographical distance from said target cluster.

6. The method of claim 3 , wherein said high precision reference measurements comprise timing advance or round trip time measurements, and wherein said merging comprises merging radially adjacent clusters to provide a region with reduced ratio between a width and thickness.

7. The method of claim 1 , wherein said high precision reference measurements comprise GSM configuration Assisted Global Positioning System (A-GPS) reference measurements, and said tag comprises one or any subset of Cell Global Identities (CGIs), Timing Advances (TAs) and Received Signal Strengths (RSSs).

8. The method of claim 1 , wherein said high precision reference measurements comprise WCDMA configuration Assisted Global Positioning System (A-GPS) reference measurements, and said tag comprises one or any subset of Cell Identities (IDs), Round Trip Times (RTTs), pre-coding indices, and path-losses.

9. The method of claim 1 , wherein said high precision reference measurements comprise Round Trip Time (RTT) configuration Assisted Global Positioning System (A-GPS) reference measurements, or Observed Time Difference of Arrival (OTDOA) reference measurements, and wherein said tag comprises one or any subset of Cell Identities (IDs), signal strengths, and pre-coding indices.

10. An arrangement for improved clustering for providing position determination assisting data in a cellular communication system, comprising:

a clustering unit for providing a plurality of clusters of points, said points being results of high-precision reference measurements, said points of each of said cluster having the same unique radio fingerprinting tag;

an identifier for identifying a target cluster, said target cluster having a number of points less than a predetermined threshold; and

a combiner for merging said target cluster with at least one selected adjacent cluster of said provided plurality of clusters to provide a merged cluster with an increased number of high-precision reference measurements.

11. The arrangement of claim 10 , wherein the arrangement is included within a node in a telecommunication system.