03.713GPPFunctional descriptionLocation Services (LCS)Release 1999Stage 2TS
The present document defines the stage-2 service description for the LoCation Services (LCS) feature on GSM, which provides the mechanisms to support mobile location services of operators, which are not covered by standardized GSM services. CCITT I.130  describes a three-stage method for characterization of telecommunication services, and CCITT Q.65 defines stage 2 of the method.
The LCS feature is a network feature and not a supplementary service. This version of the stage 2 service description covers aspects of LCS e.g., the functional model, architecture, positioning methods, message flows etc.