. Another mobile tracking approach is proposed in [4]. The authors use a hybrid location scheme, which combines both the satellite-based and the network based signals. The proposed scheme uses the two-step Least Square method to estimate the three-dimensional position (i.e. the longitude, latitude, and altitude) of the mobile devices. The Kalman filtering technique is exploited both to eliminate the measurement noises and to track the trajectories of the mobile devices. A fusion algorithm is employed to obtain the final location estimation not only from the satellite-based but also from the network-based systems. There are already several applications in the market that offer tracking systems and anti theft applications. Anti theft application like mGuard [5], detect non-authorized SIM cards [6]. Unlike this application, the mTracker is able to enable the GPS when a non-authorized SIM card is detected in the device by comparing the Integrated Circuit Chip Card Identification (ICC ID). The ICC ID number is unique for each SIM card. Tracking applications such as, Mobile Tracking System 1.14 [7], AccuTracking [8], and PhoneBak (also anti theft application) [9], are already rooted in the mobile phone market. As it may be seen in the above-mentioned systems, most of them provide dedicate solutions using tracking methods to monitor a mobile device. Our proposal is designed for a regular mobile phone or PDA that incorporates a GPS. Unlike the systems mentioned above, the main feature of our application provides the user the ability to track a device through a predefined radius around it and to receive warnings via SMS to a predefined number when the device is out of the radius. Furthermore, Internet connection is not necessary to change the application settings or to activate the tracking feature. All this settings are accessible through the PDA itself. We have gathered suggestions of approaches in order to build the system described in the given sections. The proposed solution can furnish better functionalities and is very easy to deploy in a regular mobile phone or PDA with GPS. The mTrackerMap is also very easy to deploy in a PC. For the user safety, the mTracker application can be useful in emergency scenarios, for instance kidnapping, giving the user the ability to send distress calls via SMS.