The application is implemented as a client server system that helps users to locate their friends and receive alerts
when friends are nearby. The application works in open space areas only since it relies on GPS by calculating the
longitude and latitude values of the mobile. Future extensions may look at other options such as getting the location
from the service provider. In this case the location accuracy will be reduced and will depend on the size of the cells
where the user is located.
The main purpose of this paper is to boost the accuracy of positioning system in cellular networks. Two methods are
proposed to achieve this aim, a two-step position determination method and a one-step method. Here constrained
optimization is used to minimize the cost function. Mobile velocity and heading angle information is used for
improving the accuracy of the position. In the two-step position determination method, the position determination is
performed as the first step by applying optimization technique with NLOS mitigation to produce initial position
estimation. Mobile track geometry or motion direction information and mobile velocity are used to reduce the position
errors. In one-step position determination method a position determination scheme is proposed which handles the two
processes in one step.