Mobile phone tracking

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An indoor location tracking map on a mobile phone Indoor location services on mobile phone (10928087126).jpg
An indoor location tracking map on a mobile phone

Mobile phone tracking is a process for identifying the location of a mobile phone, whether stationary or moving. Localization may be effected by a number of technologies, such as using multilateration of radio signals between (several) cell towers of the network and the phone, or simply using GPS. To locate a mobile 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. The Global System for Mobile Communications (GSM) is based on the phone's signal strength to nearby antenna masts. [1]

Multilateration is a navigation and surveillance technique based on the measurement of the times of arrival (TOAs) of energy waves having a known propagation speed. The time origin for the TOAs is arbitrary. For surveillance, a subject of interest – in cooperative surveillance, often a vehicle – transmits to multiple receiving stations having synchronized 'clocks'. For navigation, multiple synchronized stations transmit to a user receiver. To find the coordinates of a user in n dimensions, at least n + 1 TOAs must be measured. Multilateration systems are also called hyperbolic systems, for reasons discussed below.

Cellular network communication network where the last link is wireless

A cellular network or mobile network is a communication network where the last link is wireless. The network is distributed over land areas called "cells", each served by at least one fixed-location transceiver, but more normally, three cell sites or base transceiver stations. These base stations provide the cell with the network coverage which can be used for transmission of voice, data, and other types of content. A cell typically uses a different set of frequencies from neighbouring cells, to avoid interference and provide guaranteed service quality within each cell.

Roaming is a wireless telecommunication term typically used with mobile devices. It refers to the mobile phone being used outside the range of its home network and connects to another available cell network.


Mobile positioning may include location-based services that disclose the actual coordinates of a mobile phone, which is a technology used by telecommunication companies to approximate the location of a mobile phone, and thereby also its user. [2]

A location-based service (LBS) is the name for a general class of policies in software-level services that provide for accessing data, files, pipes, memory objects, streams and other or online services. Access policies are controlled by location data and/or time-of-day constraints, or a combination thereof. As such, an LBS is an information service and has a number of uses in social networking today as information, in entertainment or security, which is accessible with mobile devices through the mobile network and which uses information on the geographical position of the mobile device.

Telecommunication Transmission of information between locations using electromagnetics

Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology. It is transmitted through a transmission media, such as over physical media, for example, over electrical cable, or via electromagnetic radiation through space such as radio or light. Such transmission paths are often divided into communication channels which afford the advantages of multiplexing. Since the Latin term communicatio is considered the social process of information exchange, the term telecommunications is often used in its plural form because it involves many different technologies.


The location of a mobile phone can be determined in a number of ways.


The location of a mobile phone can be determined using the service provider's network infrastructure. The advantage of network-based techniques, from a service provider's point of view, is that they can be implemented non-intrusively without affecting handsets. Network-based techniques were developed many years prior to the widespread availability of GPS on handsets. (See US 5519760,issued 21 May 1996  for one of the first works relating to this. [3] )

The technology of locating is based on measuring power levels and antenna patterns and uses the concept that a powered mobile phone always communicates wirelessly with one of the closest base stations, so knowledge of the location of the base station implies the cell phone is nearby.

Wireless kind of telecommunication that does not require the use of physical wires; the transfer of information or power between two or more points that are not connected by an electrical conductor

Wireless communication is the transfer of information or power between two or more points that are not connected by an electrical conductor. The most common wireless technologies use radio waves. With radio waves distances can be short, such as a few meters for Bluetooth or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications include the use of other electromagnetic wireless technologies, such as light, magnetic, or electric fields or the use of sound.

Base station

Base station is – according to the International Telecommunication Union's (ITU) Radio Regulations (RR) – a "land station in the land mobile service."

Advanced systems determine the sector in which the mobile phone is located and roughly estimate also the distance to the base station. Further approximation can be done by interpolating signals between adjacent antenna towers. Qualified services may achieve a precision of down to 50 meters in urban areas where mobile traffic and density of antenna towers (base stations) is sufficiently high. [4] Rural and desolate areas may see miles between base stations and therefore determine locations less precisely.

Urban area Human settlement with high population density and infrastructure of built environment

An urban area or urban agglomeration, is a human settlement with high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, towns, conurbations or suburbs. In urbanism, the term contrasts to rural areas such as villages and hamlets and in urban sociology or urban anthropology it contrasts with natural environment. The creation of early predecessors of urban areas during the urban revolution led to the creation of human civilization with modern urban planning, which along with other human activities such as exploitation of natural resources leads to human impact on the environment.

GSM localization uses multilateration to determine the location of GSM mobile phones, or dedicated trackers, usually with the intent to locate the user. [2]

The accuracy of network-based techniques varies, with cell identification as the least accurate (due to differential signals transposing between towers, otherwise known as "bouncing signals") and triangulation as moderately accurate, and newer "advanced forward link trilateration" timing methods as the most accurate. The accuracy of network-based techniques is both dependent on the concentration of cell base stations, with urban environments achieving the highest possible accuracy because of the higher number of cell towers, and the implementation of the most current timing methods.

One of the key challenges of network-based techniques is the requirement to work closely with the service provider, as it entails the installation of hardware and software within the operator's infrastructure. Frequently the compulsion associated with a legislative framework, such as Enhanced 9-1-1, is required before a service provider will deploy a solution.


The location of a mobile phone can be determined using client software installed on the handset. [5] This technique determines the location of the handset by putting 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 can be then sent from the handset to the carrier.

Another approach is to use a fingerprinting-based technique, [6] [7] [8] where the "signature" of the home and neighboring cells signal strengths at different points in the area of interest is recorded by war-driving and matched in real-time to determine the handset location. This is usually performed independent from the carrier.

The key disadvantage of handset-based techniques, from service provider'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, iOS, or Android, would be able to run such software, e.g. Google Maps.

One proposed work-around is the installation of embedded hardware or software on the handset by the manufacturers, e.g., Enhanced Observed Time Difference (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.


Using the subscriber identity module (SIM) in GSM and Universal Mobile Telecommunications System (UMTS) handsets, it is possible to obtain raw radio measurements from the handset. [9] [10] Available measurements include the serving Cell ID, round-trip time, and signal strength. The type of information obtained via the SIM can differ from that which 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.


Crowdsourced Wi-Fi data can also be used to identify a handset's location. [11] The poor performance of the GPS-based methods in indoor environment and the increasing popularity of Wi-Fi have encouraged companies to design new and feasible methods to carry out Wi-Fi-based indoor positioning. [12] Most smartphones combine Global Navigation Satellite Systems (GNSS), such as GPS and GLONASS, with Wi-Fi positioning systems.

Hybrid positioning system

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 its 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. Such systems include Google Maps, as well as, LTE's OTDOA and E-CellID.

There are also hybrid positioning systems which combine several different location approaches to position mobile devices by Wi-Fi, WiMAX, GSM, LTE, IP addresses, and network environment data.

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. [13]

Consumer applications

A phone's location can be shared with friends and family, posted to a public web site, recorded locally, or shared with other users of a smartphone app. The inclusion of GPS receivers on smartphones has made geographical apps nearly ubiquitous on these devices. Specific applications include:

In January 2019, the location of her iPhone as determined by her sister helped Boston police find kidnapping victim Olivia Ambrose. [14]


Locating or positioning touches upon delicate privacy issues, since it enables someone to check where a person is without the person's consent. [15] Strict ethics and security measures are strongly recommended for services that employ positioning.
In 2012 Malte Spitz held a TED talk [16] on the issue of mobile phone privacy in which he showcased his own stored data that he received from Deutsche Telekom after suing the company. He described the data, which consists of 35,830 lines of data collected during the span of Germany's data retention at the time, saying, "This is six months of my life [...] You can see where I am, when I sleep at night, what I'm doing." He partnered up with ZEIT Online and made his information publicly available in an interactive map which allows users to watch his entire movements during that time in fast-forward. Spitz concluded that technology consumers are the key to challenging privacy norms in today's society who "have to fight for self determination in the digital age." [17] [18]


Chinese government has proposed using this technology to track commuting patterns of Beijing city residents. [19] Aggregate presence of mobile phone users could be tracked in a privacy-preserving fashion. [20]


In Europe most countries have a constitutional guarantee on the secrecy of correspondence, and location data obtained from mobile phone networks is usually given the same protection as the communication itself.[ citation needed ]

United States

In the United States, there is a limited constitutional guarantee on the privacy of telecommunications through the Fourth Amendment. [21] [22] [23] [24] [25] The use of location data is further limited by statutory, [26] administrative, [27] and case law. [21] [28] Police access of seven days of a citizen's location data is unquestionably enough to be a fourth amendment search requiring both probable cause and a warrant. [21] [29]

In November 2017, the United States Supreme Court ruled in Carpenter v. United States that the government violates the Fourth Amendment by accessing historical records containing the physical locations of cellphones without a search warrant.[ citation needed ]

See also

Related Research Articles

GSM standard to describe protocols for second generation digital cellular networks used by mobile phones

The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile devices such as mobile phones and tablets. It was first deployed in Finland in December 1991.By the mid-2010s, it became a global standard for mobile communications achieving over 90% market share, and operating in over 193 countries and territories.

Enhanced 911, E-911 or E911 is a system used in North America to automatically provide the caller's location to 911 dispatchers. 911 is the universal emergency telephone number in the region. In the European Union, a similar system exists known as E112 and known as eCall when called by a vehicle.

Cell site cellular telephone site where antennae and electronic communications equipment are placed — typically on a radio mast, tower, or other raised structure — to create a cell (or adjacent cells) in a cellular network

A cell site, cell tower, or cellular base station is a cellular-enabled mobile device site where antennae and electronic communications equipment are placed—typically on a radio mast, tower, or other raised structure—to create a cell in a cellular network. The raised structure typically supports antenna and one or more sets of transmitter/receivers transceivers, digital signal processors, control electronics, a GPS receiver for timing, primary and backup electrical power sources, and sheltering.

Satellite phone type of mobile phone

A satellite telephone, satellite phone or satphone is a type of mobile phone that connects to other phones or the telephone network by radio through orbiting satellites instead of terrestrial cell sites, as cellphones do. The advantage of a satphone is that its use is not limited to areas covered by cell towers; it can be used in most or all geographic locations on the Earth's surface.

Mobile telephony collective term for the operation of mobile telephone devices

Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur.

Assisted GPS System to improve the time-to-first-fix of a GPS receiver

Assisted GPS or Augmented GPS is a system that often significantly improves the startup performance—i.e., time-to-first-fix (TTFF)—of a GPS satellite-based positioning system. A-GPS is extensively used with GPS-capable cellular phones, as its development was accelerated by the U.S. FCC's 911 requirement to make cell phone location data available to emergency call dispatchers.

Radiolocating is the process of finding the location of something through the use of radio waves. It generally refers to passive uses, particularly radar—as well as detecting buried cables, water mains, and other public utilities. It is similar to radionavigation, but radiolocation usually refers to passively finding a distant object rather than actively one's own position. Both are types of radiodetermination. Radiolocation is also used in real-time locating systems (RTLS) for tracking valuable assets.

An international mobile subscriber identity-catcher, or IMSI-catcher, is a telephone eavesdropping device used for intercepting mobile phone traffic and tracking location data of mobile phone users. Essentially a "fake" mobile tower acting between the target mobile phone and the service provider's real towers, it is considered a man-in-the-middle (MITM) attack. The 3G wireless standard offers some risk mitigation due to mutual authentication required from both the handset and the network. However, sophisticated attacks may be able to downgrade 3G and LTE to non-LTE network services which do not require mutual authentication.

Thuraya is a United Arab Emirates-based regional mobile-satellite service (MSS) provider. The company operates two geosynchronous satellites and provides telecommunications coverage in more than 161 countries in Europe, the Middle East, North, Central and East Africa, Asia and Australia. Thuraya’s L-band network delivers voice and data services

gpsOne is the brand name for a cellphone chipset manufactured by Qualcomm for mobile phone tracking. It uses A-GPS or Assisted-GPS to locate the phone more quickly, accurately and reliably than by GPS alone, especially in places with poor GPS reception.

Generic Access Network (GAN) is a protocol that extends mobile voice, data and multimedia applications over IP networks. Unlicensed Mobile Access (UMA) is the commercial name used by mobile carriers for external IP access into their core networks. The latest generation system is named Wi-Fi Calling or VoWiFi by a number of handset manufacturers, including Apple and Samsung, a move that is being mirrored by carriers like T-Mobile US and Vodafone. The service is dependent on IMS, IPsec and ePDG.

This is a comparison of standards of mobile phones. A new generation of cellular standards has appeared approximately every tenth year since 1G systems were introduced in 1979 and the early to mid-1980s.

Mobile phone signal

A mobile phone signal is the signal strength received by a mobile phone from a cellular network. Depending on various factors, such as proximity to a tower, any obstructions such as buildings or trees, etc. this signal strength will vary. Most mobile devices use a set of bars of increasing height to display the approximate strength of this received signal to the mobile phone user. Traditionally five bars are used.

Enhanced GPS is a technology designed for mobile phones on GSM and W-CDMA networks, to augment GPS signals to deliver faster location fixes, lower cost implementations and reduced power and processing requirements. It is being developed by CSR who has partnered with Motorola – together they intend to create an open industry forum.

Simultaneous GPS or S-GPS is a method to enhance a mobile phone's satellite-based position reporting ability to a mobile network operator.

Stingray phone tracker cellular phone surveillance device

The StingRay is an IMSI-catcher, a controversial cellular phone surveillance device, manufactured by Harris Corporation. Initially developed for the military and intelligence community, the StingRay and similar Harris devices are in widespread use by local and state law enforcement agencies across Canada, the United States, and in the United Kingdom. Stingray has also become a generic name to describe these kinds of devices.

Cellphone surveillance may involve the tracking, bugging, monitoring, interception and recording of conversations and text messages on mobile phones. It also encompasses the monitoring of people's movements, which can be tracked using mobile phone signals when phones are turned on. In the United States, law enforcement agencies can legally monitor the movements of people from their mobile phone signals upon obtaining a court order to do so. Cellphone spying software is software that is surreptitiously installed on mobile phones that can enable these actions.


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  21. 1 2 3 Carpenter v. United States , 583U.S. ( Supreme Court of the United States 22 June 2018)("The Government’s acquisition of Carpenter’s cell-site records was a Fourth Amendment search.").
  22. Riley v. California , 573U.S. ( Supreme Court of the United States 25 June 2014)("Required a warrant to search mobile telecommunications devices.").
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  25. Ex parte Jackson , 96U.S.727 ( Supreme Court of the United States 1878)("Letters and sealed packages subject to letter postage in the mail can be opened and examined only under like warrant, issued upon similar oath or affirmation, particularly describing the thing to be seized, as is required when papers are subjected to search in one's own household. The constitutional guaranty of the right of the people to be secure in their papers against unreasonable searches and seizures extends to their papers, thus closed against inspection, wherever they may be.").
  26. "Stored Communications Act (18 U.S. Code § 2703(d) - Required disclosure of customer communications or records)". Requirements for Court Order.— A court order for disclosure under subsection (b) or (c) may be issued by any court that is a court of competent jurisdiction and shall issue only if the governmental entity offers specific and articulable facts showing that there are reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation. In the case of a State governmental authority, such a court order shall not issue if prohibited by the law of such State. A court issuing an order pursuant to this section, on a motion made promptly by the service provider, may quash or modify such order, if the information or records requested are unusually voluminous in nature or compliance with such order otherwise would cause an undue burden on such provider.
  27. "47 CFR Part 0, Subpart E - Privacy Act Regulations".
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  29. Liptak, Adam (23 June 2018). "Warrant Required for Cellphone Tracking Data" (print). CLXII (58, 002) (National ed.). The New York Times. pp. A1, A16. Retrieved 23 June 2018. “We decline to grant the state unrestricted access to a wireless carrier’s database of physical location information,” Chief Justice John G. Roberts Jr. wrote for the majority. ... “Mapping a cellphone’s location over the course of 127 days provides an all-encompassing record of the holder’s whereabouts,” he wrote, going on to quote from an earlier opinion. “As with GPS information, the time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religious and sexual associations.’” ... “cellphones and the services they provide are ‘such a pervasive and insistent part of daily life’ that carrying one is indispensable to participation in modern society.”