11 Position calculation functionality

03.713GPPFunctional descriptionLocation Services (LCS)Release 1999Stage 2TS

11.1 TA

For the TA once the cell-ID and TA value has been returned to the MLC, the MLC PCF should map this information into a standardized format suitable for the client. This may infer either just passing the received information in its current format or representing the area in some manner.

11.2 Time Of Arrival (TOA) Positioning mechanism

For the TOA positioning mechanism once the cell-IDs, TOA values and TOA measurement quality information has been returned to the SMLC, the SMLC PCF should estimate the position of the MS based on this information and MLC prior knowledge of RTDs and LMU co-ordinates. The estimated MS position is then mapped and/or converted into a standardized format suitable for the requesting client.

11.3 Enhanced Observed Time Difference (E-OTD)

For the E-OTD positioning mechanism once the Cell IDs (or possibly in case of neighbor BTSs the Channel and BSIC information), TA value to the serving BTS, E-OTD values and E-OTD measurement quality information have been returned to the MLC, the MLC PCF should estimate the position of the MS based on this information and MLC prior knowledge of RTDs and BTS coordinates. The estimated MS position is then mapped and/or converted into a standardized format suitable for the requesting application.

11.4 Global Positioning System (GPS) positioning mechanism

For the case where the PCF is in the GPS-equipped MS, the MS measures the phases of signals transmitted by the GPS satellites. Subsequently, the MS uses these measurements along with information describing the respective satellite positions to estimate its own position. The MS may choose to use assistance data available from within or outside of the GSM network during measurement and position computation, but this is not mandatory. The MS returns the position estimate to the MLC, along with an estimate of the position accuracy. The estimated MS position is then mapped and/or converted into a standardized format suitable for the requesting application.

For the case where the PCF is in the MLC, the MS measures the phases of signals transmitted by the GPS satellites. The MS may choose to use assistance data available from within or outside of the GSM network to aid the measurement process, but this is not mandatory. The MS returns the measurements and associated quality estimates to the MLC. The MLC uses these results plus the cell-ID (location) of the serving BTS, time-measurement results from the GEMU, and information describing the positions of the satellites measured by the MS to estimate the MS’s position. The estimated MS position is then mapped and/or converted into a standardized format suitable for the requesting application.