Mobile phone tracking

GSM tracking refers to the location of a switched-on and logged- in a radio network, based on Global System for Mobile Communications (GSM) operated terminal ( mobile phone) by the cellular network.

Basics

The position of a mobile phone is known for the cellular operator by the permanent registration on the network within certain accuracy limits. In standby mode it is at least given by the assignment to the location currently used area. This information is periodically updated upon movement of the mobile station and stored in a database, the home location register (HLR). In conversation mode, the position of a mobile phone can be determined more accurately, since at least the Cell-ID is known here of the active base station. Here there are several refinements.

GSM positioning is, depending on the application, a simple alternative to the Global Positioning System (GPS), since the mobile device does not have more infrastructure is required. The GSM positioning is, however, in comparison to determine location using GPS, most accurate, since the figures used for location determination signals have systemic tolerances and, due to the infrastructure used, factors such widely varying propagation conditions, topography of the underlying mobile network, geographical features and facilities of take used terminal on the result of influence.

Variants

A GSM tracking can be done with different measurement methods, which differ, the available options in terms of accuracy, the necessary hardware complexity in the mobile network and the requirements of the terminal and complement.

  • Method without any additional equipment, neither network nor on the device side Cell ID or Cell of Origin: This method is not specified in the 3GPP, was and is still used by network operators for rough positioning. In this method, only the cell in which the terminal is located at the time of measurement, and determines the position of use. There are no changes to network or terminal side necessity, although the achieved accuracy is low and is directly related to the density of base stations.
  • Timing Advance ( TA): the position of the terminal based on the position of the radio cell used and the timing advance parameter is determined during the procedure. The precision of the data depends on the precision of the parameter timing advance, which may be no better than 277 m due to the system.
  • Uplink Time Difference of Arrival ( U- TDOA ): In this method, the position of the terminal based on the runtime of the signals of the terminal to a specific place in the mobile network, called the Location Measurement Units (LMU ) is determined.
  • Enhanced Observed Time Difference ( E-OTD ), the position of the terminal is based on time of flight measurements of a plurality of neighboring base stations, performing the terminal, determined in this process.
  • Global Navigation Satellite System (GNSS ), the position of the terminal is determined by the terminal itself and forwarded to the mobile radio network during the procedure. The terminal determines its position using any satellite-based positioning system (GPS, Galileo, GLONASS, QZSS ). A special form of this process is Assisted GNSS (A- GNSS), in which the necessary for positioning assistance data is provided by the cellular network. In the name of this procedure normally the name of the satellite navigation system used in each case is used instead of the generic term GNSS, or about A- GPS.

The accuracy of the detected positions are from several kilometers when using Cell ID, under unfavorable conditions, between 25 m for E-OTD and U- TDOA to less than 5 m using GNSS.

Applications

  • Location-based services: The user is location-dependent information provided, for example, information on the nearest pharmacy to the cinema or to nearby restaurants.
  • Locating stolen or lost devices: Despite the systemic inaccuracies lost or stolen devices can be more easily found.
  • Location identification and tracking of objects and people: Through small and lightweight GSM terminals of the location of objects or persons can be detected. Parents can, for example, bring the whereabouts of your children in experience or the location of a stolen bicycle or motor vehicle can be determined. For customers of O2, a mobile locating is free of charge, provided that the placed in the customer area of the website cell phone finder service is being used. Automatic monitoring of individuals by their mobile device, such as a spouse without his consent, is a violation of their self-determination.
  • Fleet management for transport companies
  • Location determination under emergency calls: At the request of the emergency services can be determined (see eCall) following an emergency call, the location of the caller. The use of emergency services allows you to quickly find accident victims, as these are often not fully aware of their whereabouts or specify false. In some countries (eg the United States ) is an emergency call automatically determines and communicates the position of the participant.
  • Police investigation: in the course of criminal investigations due to serious crime or in exigent circumstances may, upon prior judicial order, the location of a terminal can be performed. A special case is the silent SMS, with the net on the precise location of a mobile phone without taking note of a connection setup can be forced by the user. This method is used in law enforcement as a tool of the police, with reference to " imminent danger ", this is done in part without judicial oversight. This practice is controversial. In total, over 1.7 million silent SMS were sent to locate suspects, according to federal authorities in recent years in Germany.
  • The German customs system uses its Patras system for locating suspects.
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