Mobile phone tracking
Encyclopedia
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 service
s (LBS).
s, so knowledge of the location of the base station implies the cell phone is nearby.
Advanced systems determine the sector in which the mobile phone resides 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 area
s where mobile traffic and density of antenna towers (base stations) is sufficiently high. Rural
and desolate areas may see miles between base stations and therefore determine locations less precisely.
GSM localization is the use of multilateration
to determine the location of GSM
mobile phone
s, or dedicated trackers, usually with the intent to locate the user.
Localization-Based Systems can be broadly divided into:
The accuracy of network-based techniques varies, with cell identification as the least accurate and triangulation
as moderately accurate, and newer "Forward Link" timing methods as the most accurate. The accuracy of network-based techniques is both dependent on the concentration of base station cells, with urban environments achieving the highest possible accuracy, 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. Often, a legislative framework, such as E911, would need to be in place to compel the cooperation of the service provider as well as to safeguard the privacy of the information.
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, smartphone
s, 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.
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.
s 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 (ie 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 tracking are Mologogo, instaMapper, Buddyway and Google Latitude
.
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 is the antenna pattern that 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.
which could be used in a similar fashion, but with much higher accuracy.
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.
Some "Free" tracking services allow the cellular telephone number being tracked to be added to telemarketers' lists.
China
has proposed using this technology to track commuting patterns of Beijing
city residents.
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
, stationary or moving. Localization may occur either via multilateration
Multilateration
Multilateration is a navigation technique based on the measurement of the difference in distance to two or more stations at known locations that broadcast signals at known times. Unlike measurements of absolute distance or angle, measuring the difference in distance results in an infinite number of...
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
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
companies to approximate where a mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
, 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 service
Location-based service
A Location-Based Service is an information or entertainment service, accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical position of the mobile device....
s (LBS).
Technology
The technology of locating is based on measuring power levels and antenna patterns and uses the concept that a mobile phone always communicates wirelessly with one of the closest base stationBase station
The term base station can be used in the context of land surveying and wireless communications.- Land surveying :In the context of external land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS...
s, so knowledge of the location of the base station implies the cell phone is nearby.
Advanced systems determine the sector in which the mobile phone resides 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 area
Urban area
An urban area is characterized by higher population density and vast human features in comparison to areas surrounding it. Urban areas may be cities, towns or conurbations, but the term is not commonly extended to rural settlements such as villages and hamlets.Urban areas are created and further...
s where mobile traffic and density of antenna towers (base stations) is sufficiently high. Rural
Rural
Rural areas or the country or countryside are areas that are not urbanized, though when large areas are described, country towns and smaller cities will be included. They have a low population density, and typically much of the land is devoted to agriculture...
and desolate areas may see miles between base stations and therefore determine locations less precisely.
GSM localization is the use of multilateration
Multilateration
Multilateration is a navigation technique based on the measurement of the difference in distance to two or more stations at known locations that broadcast signals at known times. Unlike measurements of absolute distance or angle, measuring the difference in distance results in an infinite number of...
to determine the location of GSM
Global System for Mobile Communications
GSM , is a standard set developed by the European Telecommunications Standards Institute to describe technologies for second generation digital cellular networks...
mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
s, or dedicated trackers, usually with the intent to locate the user.
Localization-Based Systems can be broadly divided into:
- Network-based
- Handset-based
- SIM-based
- Hybrid
Network-based
Network-based techniques utilize the service provider's network infrastructure to identify the location of the handset. The advantage of network-based techniques (from mobile operator's point of view) is that they can be implemented non-intrusively, without affecting the handsets.The accuracy of network-based techniques varies, with cell identification as the least accurate and triangulation
Triangulation
In trigonometry and geometry, triangulation is the process of determining the location of a point by measuring angles to it from known points at either end of a fixed baseline, rather than measuring distances to the point directly...
as moderately accurate, and newer "Forward Link" timing methods as the most accurate. The accuracy of network-based techniques is both dependent on the concentration of base station cells, with urban environments achieving the highest possible accuracy, 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. Often, a legislative framework, such as E911, would need to be in place to compel the cooperation of the service provider as well as to safeguard the privacy of the information.
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, smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...
s, such as one based on Symbian
Symbian
Symbian is a mobile operating system and computing platform designed for smartphones and currently maintained by Accenture. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user...
, Windows Mobile
Windows Mobile
Windows Mobile is a mobile operating system developed by Microsoft that was used in smartphones and Pocket PCs, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone, which does not run Windows Mobile software.Windows Mobile is...
, Windows Phone
Windows Phone
Windows Phone is a mobile operating system developed by Microsoft, and is the successor to its Windows Mobile platform, although incompatible with it. Unlike its predecessor, it is primarily aimed at the consumer market rather than the enterprise market...
, BlackBerry OS
BlackBerry OS
BlackBerry OS is a proprietary mobile operating system, developed by Research In Motion for its BlackBerry line of smartphone handheld devices...
, iPhone
IPhone
The iPhone is a line of Internet and multimedia-enabled smartphones marketed by Apple Inc. The first iPhone was unveiled by Steve Jobs, then CEO of Apple, on January 9, 2007, and released on June 29, 2007...
, 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
Using the SIM in GSM and UMTSUniversal Mobile Telecommunications System
Universal Mobile Telecommunications System is a third generation mobile cellular technology for networks based on the GSM standard. Developed by the 3GPP , UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for...
handsets, it is possible to obtain raw radio measurements from the handset. The measurements that are available can include the serving Cell ID
Cell ID
A GSM Cell ID is a generally unique number used to identify each Base transceiver station or sector of a BTS within a Location area code if not within a GSM network.In some cases the last digit of CID represents cells' Sector 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
Hybrid positioning systemHybrid positioning system
Hybrid positioning systems are systems for finding the location of a mobile device using several different positioning technologies. Usually GPS is one major component of such systems, combined with cell tower signals, wireless internet signals, Bluetooth sensors or other local Positioning...
s use a combination of network-based and handset-based technologies for location determination. One example would be some modes of Assisted GPS
Assisted GPS
Assisted GPS, generally abbreviated as A-GPS or aGPS, is a system which can, under certain conditions, improve the startup performance, or time-to-first-fix of a GPS satellite-based positioning system. It is used extensively with GPS-capable cellular phones as its development was accelerated by...
, 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 (ie 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 tracking are Mologogo, instaMapper, Buddyway and Google Latitude
Google Latitude
Google Latitude is a location-aware mobile app developed by Google as a successor to their earlier SMS-based service Dodgeball. Latitude allows a mobile phone user to allow certain people to view their current location. Via their own Google Account, the user's cell phone location is mapped on...
.
Operational purpose
In order to route calls to a phone the cell towersCell site
A cell site is a term used to describe a site where antennas and electronic communications equipment are placed, usually on a radio mast, tower or other high place, to create a cell in a cellular network...
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 is the antenna pattern that 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 web site where one's "friends and family" can view one's last reported position. Newer phones may have built-in GPS receiversGlobal Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
which could be used in a similar fashion, but with much higher accuracy.
Privacy
Locating or positioning touches upon delicate privacyPrivacy
Privacy is the ability of an individual or group to seclude themselves or information about themselves and thereby reveal themselves selectively...
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
Consent
Consent refers to the provision of approval or agreement, particularly and especially after thoughtful consideration.- Types of consent :*Implied consent is a controversial form of consent which is not expressly granted by a person, but rather inferred from a person's actions and the facts and...
to a service provider before the service provider can compute positioning data from the user's mobile phone.
In Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, where most countries have a constitutional guarantee on the secrecy of correspondence
Secrecy of correspondence
The secrecy of correspondence ) or literally translated as secrecy of letters, is a fundamental legal principle enshrined in the constitutions of several European countries. It guarantees that the content of sealed letters is never revealed and letters in transit are not opened by government...
, location data obtained from mobile phone networks is usually given the same protection as the communication itself. The United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
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
Police
The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...
) can obtain permission to position phones in emergency
Emergency
An emergency is a situation that poses an immediate risk to health, life, property or environment. Most emergencies require urgent intervention to prevent a worsening of the situation, although in some situations, mitigation may not be possible and agencies may only be able to offer palliative...
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
Electronic Frontier Foundation
The Electronic Frontier Foundation is an international non-profit digital rights advocacy and legal organization based in the United States...
is tracking some cases, including USA v. Pen Register, regarding government tracking of individuals.
Some "Free" tracking services allow the cellular telephone number being tracked to be added to telemarketers' lists.
China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
has proposed using this technology to track commuting patterns of Beijing
Beijing
Beijing , also known as Peking , is the capital of the People's Republic of China and one of the most populous cities in the world, with a population of 19,612,368 as of 2010. The city is the country's political, cultural, and educational center, and home to the headquarters for most of China's...
city residents.
See also
- Local positioning system
- Assisted GPSAssisted GPSAssisted GPS, generally abbreviated as A-GPS or aGPS, is a system which can, under certain conditions, improve the startup performance, or time-to-first-fix of a GPS satellite-based positioning system. It is used extensively with GPS-capable cellular phones as its development was accelerated by...
- Base stationBase stationThe term base station can be used in the context of land surveying and wireless communications.- Land surveying :In the context of external land surveying, a base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS...
- Cell siteCell siteA cell site is a term used to describe a site where antennas and electronic communications equipment are placed, usually on a radio mast, tower or other high place, to create a cell in a cellular network...
- Global Positioning SystemGlobal Positioning SystemThe Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
- Google LatitudeGoogle LatitudeGoogle Latitude is a location-aware mobile app developed by Google as a successor to their earlier SMS-based service Dodgeball. Latitude allows a mobile phone user to allow certain people to view their current location. Via their own Google Account, the user's cell phone location is mapped on...
- GPS Phone
- Locating
- Location-based serviceLocation-based serviceA Location-Based Service is an information or entertainment service, accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical position of the mobile device....
- Mobile datingMobile datingMobile dating services, also known as cell dating, cellular dating, or cell phone dating, allow individuals to chat, flirt, meet, and possibly become romantically involved by means of text messaging, mobile chatting, and the mobile web....
- Mobile phoneMobile phoneA mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
- MultilaterationMultilaterationMultilateration is a navigation technique based on the measurement of the difference in distance to two or more stations at known locations that broadcast signals at known times. Unlike measurements of absolute distance or angle, measuring the difference in distance results in an infinite number of...
- Positioning (telecommunications)
- Radio resource location services protocol
- Real-time locating
- Secure telephoneSecure telephoneA secure telephone is a telephone that provides voice security in the form of end-to-end encryption for the telephone call, and in some cases also the mutual authentication of the call parties, protecting them against a man-in-the-middle attack...
External links
- privacyrights.org - Protecting Your Privacy in the Age of the Super-Phone
- Cell Reception - Google maps API to locate cell towers in the United States
- Cellphone Tracking Powers on Request, washingtonpost.com
- GSM Localization on Mobile Phones
- OpenCellID: An OpenSource CellID database
- J2ME and Location-Based Services
- Location API for J2ME
- Handyortung Mobile Tracking for germany
- openBmap: Map and tools for a free and open Cell ID database in GPL and Creative Common Licence
- Trace mobile number location, service provider, service type of any Indian mobile number