Mobile phone tracking
May 17, 2013
Mobile phone tracking search Mobile phone tracking refers to the attaining of the current position of a mobile phone, stationary or moving. Localization may occur either via multilateration of radio signals between (several) radio towers of the network and the phone, or simply via GPS. To locate the phone using multilateration of radio signals, it must emit at least the roaming signal to contact the next nearby antenna tower, but the process does not require an active call. GSM is based on the signal strength to nearby antenna masts. Mobile positioning, which includes location based service that discloses the actual coordinates of a mobile phone bearer, is a technology used by telecommunication companies to approximate where a mobile phone, and thereby also its user (bearer), temporarily resides. The more properly applied term locating refers to the purpose rather than a positioning process. Such service is offered as an option of the class of location-based services (LBS). Handset-based Handset-based technology requires the installation of client software on the handset to determine its location. This technique determines the location of the handset by computing its location by cell identification, signal strengths of the home and neighboring cells, which is continuously sent to the carrier. In addition, if the handset is also equipped with GPS then significantly more precise location information is then sent from the handset to the carrier. The key disadvantage of this technique (from mobile operator's point of view) is the necessity of installing software on the handset. It requires the active cooperation of the mobile subscriber as well as software that must be able to handle the different operating systems of the handsets. Typically, smartphones, such as one based on Symbian, Windows Mobile, Windows Phone, BlackBerry OS, iPhone, or Android, would be able to run such software. One proposed work-around is the installation of embedded hardware or software on the handset by the manufacturers, e.g. E-OTD. This avenue has not made significant headway, due to the difficulty of convincing different manufacturers to cooperate on a common mechanism and to address the cost issue. Another difficulty would be to address the issue of foreign handsets that are roaming in the network. SIM-based [edit] Using the SIM in GSM and UMTS handsets, it is possible to obtain raw radio measurements from the handset. The measurements that are available can include the serving Cell ID, round trip time and signal strength. The type of information obtained via the SIM can differ from what is available from the handset. For example, it may not be possible to obtain any raw measurements from the handset directly, yet still obtain measurements via the SIM. Hybrid [edit] Hybrid positioning systems use a combination of network-based and handset-based technologies for location determination. One example would be some modes of Assisted GPS, which can both use GPS and network information to compute the location. Both types of data are thus used by the telephone to make the location more accurate (i.e. A-GPS). Alternatively tracking with both systems can also occur by having the phone attain his GPS-location directly from the satellites, and then having the information sent via the network to the person that is trying to locate the telephone. Services allowing such cellphone include Google Latitude. Other examples would be LTE's OTDOA and E-CellID. Wifi [edit] Crowdsourced Wifi data can also be used to identify a handset's location. Poor performance of the GPS-based methods in indoor environment and increasing popularity of WiFi have encouraged companies to design new and feasible methods to carry out WiFi-based indoor positioning. Operational purpose In order to route calls to a phone, the cell towers listen for a signal sent from the phone and negotiate which tower is best able to communicate with the phone. As the phone changes location, the antenna towers monitor the signal, and the phone is roamed to an adjacent tower as appropriate. By comparing the relative signal strength from multiple antenna towers, a general location of a phone can be roughly determined. Other means make use of the antenna pattern, which supports angular determination and phase discrimination. Newer phones may also allow the tracking of the phone even when turned on and not active in a telephone call. This results from the roaming procedures that perform hand-over of the phone from one base station to another. Bearer interest A phone's location can be uploaded to a common website where one's friends and family can view one's last reported position. Newer phones may have built-in GPS receivers which could be used in a similar fashion, but with much higher accuracy. This may be controversial, because having this data on a common website may mean that people who are not 'friends and family' may be able to view the info, most obviously, the owners of the site. Privacy [edit] Locating or positioning touches upon delicate privacy issues, since it enables someone to check where a person is without the person's consent. Strict ethics and security measures are strongly recommended for services that employ positioning, and the user must give an informed, explicit consent to a service provider before the service provider can compute positioning data from the user's mobile phone. In Europe, where most countries have a constitutional guarantee on the secrecy of correspondence, location data obtained from mobile phone networks is usually given the same protection as the communication itself. The United States, however, has no explicit constitutional guarantee on the privacy of telecommunications, so use of location data is limited by law. With tolling systems, as in Germany, the locating of vehicles is equally sensitive to the constitutional guarantee on the secrecy of correspondence, and thus any further use of tolling information beyond deducting the road fee is prohibited. Even obviously criminal intent may not be inferred by such means, although such a use is technically possible. Officially, the authorities (like the police) can obtain permission to position phones in emergency cases where people (including criminals) are missing. The U.S. Justice Department has argued that current laws allow them to track suspects without having probable cause to suspect a law is being violated. In some instances, law enforcement may even access a mobile phone's internal microphone to eavesdrop on local conversations while the phone is switched off. The Electronic Frontier Foundation is tracking some cases, including USA v. Pen Register, regarding government tracking of individuals. In the US, an interpretation of The Patriot Act that is secret, but confirmed to exist, has been linked to secret widespread location tracking. China has proposed using this technology to track commuting patterns of Beijing city residents. Aggregate presence of mobile phone users could be tracked in a privacy-preserving fashion.
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