Cell phone tracking can be defined as attaining the current position of a cell phone whether stationary or while moving. Tracking is possible in a restricted area either by multilateration of radio signals between radio towers and the cell phone or via GPS. While multilateration requires emission of roaming signal to contact next closest antenna tower without an active call, GS M is based on signal strength of closest antenna towers.
Measurement of power levels and antenna patterns coupled with the concept that cell phone always communicates wirelessly with one of the nearest base stations forms the foundation for using technology in cell phone tracking. Use of multilateration for cell phone tracking is referred to as GSM localization.
The below broad categories of localization based systems can be used for cell phone tracking:
Network based systems:
Under this system, the service provider’s network infrastructure is used to track the location of the cell phone. While the advantage of using network based system lies in its implementation without affecting handset, the disadvantage of the system lies in its level of accuracy as accuracy is dependent on concentration of base station cells and implementation of the most current timing methods. Installation of software and hardware within the operator’s infrastructure to work closely with the services provider poses a key challenge in using network based system for tracking.
Handset based systems:
Under this system, Installation of client software forms the key requirement to track the cell phone. Cell identification and signal strengths sent to carrier from from home and nearby cells determines the location of the cell phone. Precise location in formation is sent from handset to carries in case of handset being equipped with GPS. Disadvantages of using this system include the necessity of software installation on the handset, active cooperation of mobile subscriber and software with ability to handle various operating systems of handsets. Proposal of embedded software installation did not make significant headway owing to difficulties in issues with foreign handsets roaming in the network and convincing manufactures to cooperate on a common mechanism to address cost issue.
SIM based systems:
Raw audio measurements obtained from SIM of GSM and handsets helps in tracking the cell phone. Though raw measurements cannot be obtained from handset and the type of information obtained from SIM and handset vary, measurements available from SIM include serving cell ID, round trip time and signal strength.
Under this system, cell phone location is determined by usage of network and handset based technologies by hybrid positioning systems. For example, location can be computed by use of GPS and network information by some modes of assisted GPS. Another way of locating would be to attain GPS location directly from satellites and then sending the information via network to the person tracking the location.
As tracking and positioning touches delicate privacy issues by enabling checking of a person without the persons consent, it is recommended to employ strict ethics and security measures.s