Positioning of mobile device

An apparatus comprising:

• at least one processor, and
• at least one memory comprising a computer program code, wherein the processor, the memory, and the computer program code are configured to cause the apparatus to:
• determine locations of a plurality of fixed positioning nodes;
• receive a measurement report from a mobile device, the measurement report comprising a plurality of measurement values measured by the mobile device, wherein each measurement value comprises a reference signal time difference indicating a radio propagation time difference between the mobile device and two different positioning nodes;
• determine, on the basis of threshold comparison carried out by the location computer apparatus, that at least one of the plurality of measurement values is associated with an inaccurate measurement;
• modify, autonomously, said at least one of the plurality of measurement values;
• and
• compute a location of the mobile device on the basis of a plurality of measurement values resulting from said modifying,
• wherein the processor, the memory, and the computer program code are configured to cause the apparatus further to:
• form a surrounding node set for a positioning node, wherein the surrounding node set comprises a plurality of positioning nodes surrounding said positioning node, and
• wherein the processor, the memory, and the computer program code are configured to cause the apparatus to carry out said threshold comparison by performing at least the following:
• determining a measurement value comprising a reference signal time difference associated with said positioning node and another positioning node, wherein the other positioning node is not included in the surrounding node set;
• determining a maximum reference signal time difference value amongst a set of measurement values, wherein the set of measurement values comprises reference signal time difference values between said other positioning node and each positioning node of the surrounding node set;
• if said determined measurement value is higher than the determined maximum reference signal time difference value, determining the determined measurement value to be inaccurate.

A computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a method comprising:

• determining, by the apparatus, locations of a plurality of fixed positioning nodes;
• receiving, by the apparatus, a measurement report from a mobile device, the measurement report comprising a plurality of measurement values measured by the mobile device, wherein each measurement value comprises a reference signal time difference indicating a radio propagation time difference between the mobile device and two different positioning nodes;
• determining, on the basis of threshold comparison carried out by the location computer apparatus, that at least one of the plurality of measurement values is associated with an inaccurate measurement;
• modifying, autonomously by the apparatus, said at least one of the plurality of measurement values;
• and
• computing, by the apparatus, a location of the mobile device on the basis of a plurality of measurement values resulting from said modifying,
• wherein said threshold comparison comprises:
• forming a surrounding node set for a positioning node, wherein the surrounding node set comprises a plurality of positioning nodes surrounding said positioning node,
• determining a measurement value comprising a reference signal time difference associated with said positioning node and another positioning node, wherein the other positioning node is not included in the surrounding node set;
• determining a maximum reference signal time difference value amongst a set of measurement values, wherein the set of measurement values comprises reference signal time difference values between said other positioning node and each positioning node of the surrounding node set;
• if said determined measurement value is higher than the determined maximum reference signal time difference value, determining the determined measurement value to be inaccurate.