Design And Implementation Of A-GPS Location Service Platform Based On Secure User Plane

With the rapid development of mobile communication, location services are being paid more and more attention. Being the base of all location service applications, positioning technologies naturally become an important research area in mobile communication. A-GPS inherits standard GPS's advantage of high positioning accuracy, and increase much the positioning speed. A-GPS has been one of the competitive positioning technologies. SUPL, which defined by OMA, needs only least changes of networks, and can be deployed quickly. SUPL is favored by many carries because of its low cost, high flexibility and quick deployment. In Chapter 1, several positioning technologies currently used are introduced. In Chapter 2, the principle of GPS is introduced first. We get the conclusion that traditional GPS is not suitable for mobile positioning, and propose A-GPS technology, whose improvements relative to GPS are analyzed. In the last part of Chapter 2, RRLP used for transmitting positioning data is discussed briefly. In Chapter 3, the solutions about location service of 3GPP and OMA are both described, the differences of 2 solutions are discussed, and then the structure, main function modules and inner operation flow of the SULP Location Service Platform are described. In SUPL, ULP and RRLP are both described with ITU-T ASN.1 and encoded with PER. In Chapter 4, the characteristics of ASN.1 and PER are introduced first, and then the object-oriented implementation with C++ of ASN.1 based protocol and the PER encoder/decoder is described in details. In Chapter 5, positioning message flow and relative concepts such as event spring, finite state machine, State mode are discussed, and the implementation of the state machine over Lup interface with State mode is analyzed finally.