A method for calculating an estimate of the position of a mobile station, comprising: collecting in a mobile station, position estimate information "PEI" transmitted by a plurality of location nodes in one or more messages carried on at least one of a common channel or a dedicated channel, and wherein the PEI in the one or more messages includes a location node identification and longitude and latitude information of the location node of the plurality of location nodes; generating in the mobile station, PEI parameters based upon the PEI collected from the plurality of location nodes, wherein the PEI parameters include information from which at least one of the plurality of location nodes can be uniquely located or identified; and sending the PEI parameters from the mobile station to a position determination entity, wherein the PEI parameters permit calculation of the position estimate; and characterised in that the PEI parameters indicate whether or not the mobile station is currently in view of the location node, wherein: if the mobile station is not currently in view of the location node, the PEI parameters include velocity estimation of the mobile station, and/or information relating to elapsed time which the mobile station has been out of view of the location node; or if the mobile station is currently in view of the location node, the PEI parameters include information relating to proximity of the mobile station relative to the location node. collecting in a mobile station, position estimate information "PEI" transmitted by a plurality of location nodes in one or more messages carried on at least one of a common channel or a dedicated channel, and wherein the PEI in the one or more messages includes a location node identification and longitude and latitude information of the location node of the plurality of location nodes; generating in the mobile station, PEI parameters based upon the PEI collected from the plurality of location nodes, wherein the PEI parameters include information from which at least one of the plurality of location nodes can be uniquely located or identified; and sending the PEI parameters from the mobile station to a position determination entity, wherein the PEI parameters permit calculation of the position estimate; and characterised in that the PEI parameters indicate whether or not the mobile station is currently in view of the location node, wherein: if the mobile station is not currently in view of the location node, the PEI parameters include velocity estimation of the mobile station, and/or information relating to elapsed time which the mobile station has been out of view of the location node; or if the mobile station is currently in view of the location node, the PEI parameters include information relating to proximity of the mobile station relative to the location node. if the mobile station is not currently in view of the location node, the PEI parameters include velocity estimation of the mobile station, and/or information relating to elapsed time which the mobile station has been out of view of the location node; or if the mobile station is currently in view of the location node, the PEI parameters include information relating to proximity of the mobile station relative to the location node.