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Enhanced Observed Time Difference
Enhanced Observed Time Difference (E-OTD) is a standard for the location of mobile telephones. The location method works by multilateration. The standardisation was first carried out for GSM by the GSM standard committees (T1P1.5 and ETIS) in LCS Release 98 and Release 99. The standardisation was continued for 3G and WCDMA mobile telephones by 3GPP. Conceptually, the method is similar to U-TDOA, however, it involves time difference measurements being made in the handset rather than the network, and a mechanism to pseudo-synchronise the network. The handset makes an observation of the time difference of arrival of signals from two different base stations. These observations are known as Observed Time Difference (OTD). The handset measures the OTD between a number of different base stations. If the base stations were synchronised, then a single OTD defines a hyperbolic locus. A second, independent OTD, for which one of the observed base stations is spatially distinct from those in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Telephone
A mobile phone or cell phone is a portable telephone that allows users to make and receive calls over a radio frequency link while moving within a designated telephone service area, unlike fixed-location phones ( landline phones). This radio frequency link connects to the switching systems of a mobile phone operator, providing access to the public switched telephone network (PSTN). Modern mobile telephony relies on a cellular network architecture, which is why mobile phones are often referred to as 'cell phones' in North America. Beyond traditional voice communication, digital mobile phones have evolved to support a wide range of additional services. These include text messaging, multimedia messaging, email, and internet access (via LTE, 5G NR or Wi-Fi), as well as short-range wireless technologies like Bluetooth, infrared, and ultra-wideband (UWB). Mobile phones also support a variety of multimedia capabilities, such as digital photography, video recording, and gaming. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multilateration
Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth ( geopositioning). When more than three distances are involved, it may be called multilateration, for emphasis. The distances or ranges might be ordinary Euclidean distances ( slant ranges) or spherical distances (scaled central angles), as in '' true-range multilateration''; or biased distances ( pseudo-ranges), as in '' pseudo-range multilateration''. Trilateration or multilateration should not be confused with '' triangulation'', which uses angles for positioning; and '' direction finding'', which determines the line of sight direction to a target without determining the radial distance. Terminology Multiple, sometimes overlapping and conflicting terms are employed for similar concepts – e.g., ''multilateration'' without modification has been used for aviation systems employing both true-ranges and pseudo-ranges."Multilatera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WCDMA
The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. UMTS uses wideband code-division multiple access (W- CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators compared to previous 2G systems like GPRS and CSD. UMTS on its provides a peak theoretical data rate of 2 Mbit/s. Developed and maintained by the 3GPP (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM. UMTS specifies a complete network system, which includes the radio access network ( UMTS Terrestrial Radio Access Network, or UTRAN), the core network ( Mobile Application Part, or MAP) and the authenti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhanced 911
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 (where 112 is the emergency access number) and known as eCall when called by a vehicle. An incoming 911 call is routed to a Public Safety Answering Point (PSAP), which is a call center operated by the local government. At the PSAP, the call is answered by a specially trained official known as a 9-1-1 dispatcher. The dispatcher's computer receives information from the telephone company about the physical address (for landlines) or geographic coordinates (for wireless) of the caller. This information is used to dispatch police, fire, medical and other services as needed. The planned replacement service is NG911. Call routing Landline routing Calls to 911 over the public switched telephone network (PSTN) are routed to a specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSR Plc
CSR plc (formerly Cambridge Silicon Radio) was a multinational fabless semiconductor company headquartered in Cambridge, United Kingdom. Its main products were connectivity, audio, imaging and location chips. CSR was listed on the London Stock Exchange and was a constituent of the FTSE 250 Index until it was acquired by Qualcomm in August 2015. Under Qualcomm's ownership, the company was renamed Qualcomm Technologies International, Ltd. History The company was founded in 1998 and split away from Cambridge Consultants as ''Cambridge Silicon Radio'' or CSR in 1999. The founding directors, who were all at Cambridge Consultants at the time were Phil O'Donovan, James Collier and Glenn Collinson. It was first listed on the London Stock Exchange in 2004. In 2005 the company acquired Clarity Technologies, a leading clear voice capture (CVC) business and UbiNetics, a 3G wireless ( WCDMA/UMTS/ HSDPA) technology company. In 2007, CSR acquired Nordnav, a Swedish-based GPS softwar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real Time Locating
Real-time locating systems (RTLS), also known as real-time tracking systems, are used to automatically identify and track the location of objects or people in real time, usually within a building or other contained area. Wireless RTLS tags are attached to objects or worn by people, and in most RTLS, fixed reference points receive wireless signals from tags to determine their location. Examples of real-time locating systems include tracking automobiles through an assembly line, locating pallets of merchandise in a warehouse, or finding medical equipment in a hospital. The physical layer of RTLS technology is often radio frequency (RF) communication. Some systems use optical (usually infrared) or acoustic (usually ultrasound) technology with, or in place of RF, RTLS tags. And fixed reference points can be transmitters, receivers, or both resulting in numerous possible technology combinations. RTLS are a form of local positioning system and do not usually refer to GPS or to m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multilateration
Trilateration is the use of distances (or "ranges") for determining the unknown position coordinates of a point of interest, often around Earth ( geopositioning). When more than three distances are involved, it may be called multilateration, for emphasis. The distances or ranges might be ordinary Euclidean distances ( slant ranges) or spherical distances (scaled central angles), as in '' true-range multilateration''; or biased distances ( pseudo-ranges), as in '' pseudo-range multilateration''. Trilateration or multilateration should not be confused with '' triangulation'', which uses angles for positioning; and '' direction finding'', which determines the line of sight direction to a target without determining the radial distance. Terminology Multiple, sometimes overlapping and conflicting terms are employed for similar concepts – e.g., ''multilateration'' without modification has been used for aviation systems employing both true-ranges and pseudo-ranges."Multilatera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geopositioning
Geopositioning is the process of determining or estimating the geographic position of an object or a person. Geopositioning yields a set of geographic coordinates (such as latitude and longitude) in a given map datum. Geographic positions may also be expressed indirectly, as a distance in linear referencing or as a bearing and range from a known landmark. In turn, positions can determine a meaningful location, such as a street address. Geoposition is sometimes referred to as ''geolocation'', and the process of geopositioning may also be described as ''geo-localization''. Specific instances include: * animal geotracking, the process of inferring the location of animals over time; * positioning system, the mechanisms for the determination of geographic positions in general; * internet geolocation, geolocating a device connected to the internet; * and mobile phone tracking. Geofencing ''Geofencing'' involves creating a virtual geographic boundary (a geofence), enabling software ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GSM Standard
The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation ( 2G) digital cellular networks, as used by mobile devices such as mobile phones and mobile broadband modems. GSM is also a trade mark owned by the GSM Association. "GSM" may also refer to the voice codec initially used in GSM. 2G networks developed as a replacement for first generation ( 1G) analog cellular networks. The original GSM standard, which was developed by the European Telecommunications Standards Institute (ETSI), originally described a digital, circuit-switched network optimized for full duplex voice telephony, employing time division multiple access (TDMA) between stations. This expanded over time to include data communications, first by circuit-switched transport, then by packet data transport via its upgraded standards, GPRS and then EDGE. GSM exists in various versions based on the frequency bands used. GSM was first implemented in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
