3GPP - 3rd Generation Partnership Project
3GPP is a global co-operation between six Organizational Partners (ARIB, CWTS, ETSI, T1, TTA and TTC) who are recognized as being the world's major standardization bodies from Japan, China, Europe, USA and Korea. The group is developing technical specifications for the migration of GSM to W-CDMA, the International Telecommunication Union's (ITU) framework for third-generation mobile wireless standards.
3GPP2 - 3rd Generation Partnership Project 2
Collaborative third generation (3G) telecommunications standards-setting project comprising North American and Asian interests developing global specifications for ANSI/TIA/EIA-41 "Cellular Radio Telecommunication Intersystem Operations network evolution to 3G, and global specifications for the radio transmission technologies (RTTs) supported by ANSI/TIA/EIA-41
A-GPS – Assisted GPS
A technique of providing a GPS receiver with data (or equivalent information) that it would ordinarily have to download from the GPS satellites. This technique speeds the satellite acquisition time, and the time-to-fix of the GPS receiver.
AFLT - Advanced Forward Link Trilateration
A geo-location technique standardized by 3GPP2 that utilizes the mobile station's (MS) measured time of arrival of radio signals from the base stations (and, possibly, other terrestrial measurements).
AGC
Automatic Gain Control.
Closed-loop control system that keeps amplifier gain constant under varying signal strength conditions. Typically used in the IF portion of the receiver. In GPS systems, which have a negative SNR at the IF stage, the AGC operates not on signal but on noise power.
AMPS
Advanced Mobile Phone Service. A first-generation frequency division duplex analog radiotelephone standard used primarily in North America, Central America and South America. AMPS uses a total of 50 MHz of spectrum: 25 MHz at 824-849 for uplink transmission and 25 MHz at 869-894 MHz for downlink transmission, using 30 kHz channel separation. D-AMPS is the digital version of the standard.
ANSI
American National Standards Institute. Specify standrads for implementation of Location Based Services, and E911 implementation.
AOA - Angle of Arrival
Network based positioning method that measures the angle at which radio signals arrive at multiple points.
API - Application Programming Interface
A set of definitions of the ways in which one piece of computer software communicates with another. Typically used to provide a well-defined functional interface that is used by other software element(s).
ARIB
Association of Radio Industries and Businesses - An incorporated body designated by the Ministry of Posts and Communication of the Japanese government to pursue effective radio utilization in the radio communication and broadcast sector.
ARPU
Average Revenue Per User. A marketing and financial measure used by wireless service providers.
ASIC - Application Specific Integrated Circuit
Customized microchip designed to perform a very specific task, normally in real time. ASIC design involves taking common functions from a library and integrating them onto a circuit. Examples are GPS signal correlators, video accelerators
Almanac
An approximation of the orbit models of the entire constellation of GPS satellites. Typically used for acquiring satellite signals rather than calculating position. It is valid for a period of months. In comparison, ephemeris data is valid only for a matter of hours.
Automatic Vehicle Location - AVL
A type of system using any sort of technology to track or locate a vehicle
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BAUD
Symbols per seconds. Measure of the speed of a communications channel. Different than bps (one symbol may represent several bits)
BPS - Bits Per Second
Measure of speed of a communications channel.
BTS - Base Transceiver Station
Cellular transmitter. Also referred to simply as base station.
Bluetooth
Short range radio technology expanding wireless connectivity to personal and business mobile devices enabling users to connect their mobile phones, computers, printers, digital cameras and other electronic devices to one another without cables.
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C-Plane- Control Plane
Refers to the LCS architecture and method of using the control channel to carry assistance data and location responses. In this method, the voice call and location information are directly associated with each other. Used for implementing E911/E112 services.
CB - Cell Broadcast - CBSMS
Short Message (text or binary) that is broadcasted to all subscribers within a cell.
CDMA - Code Division Multiple Access
A second-generation digital communication technology used in both cellular and PCS wireless telephony. It assigns unique matching codes to each separate pair of listeners and speakers, thereby enabling them to be transmitted over the same channel. CDMA combines several smaller channels into one larger channel by using spread spectrum technology. Other technologies used are GSM PDC & TDMA. In 1999, 13% of the world’s cell-phones were CDMA (source: EMC World Cellular Database).
CDMA2000
Cdma2000 is a radio transmission technology for the evolution of narrowband cdmaOne/IS-95 to 3rd-generation adding up multiple carriers. See also WCDMA for single carrier/direct spread technology.
CDPD - Cellular Digital Packet Data
A technology for transmitting data only over analog cellular networks. Requires a special modem, and a carrier network that has been upgraded to accommodate such data transmissions.
Cold Start
A-GPS receiver powers-up and performs a location fix without any stored frequency or time information.
Colinear
Relating to cell-towers: towers are co-linear if they lie along the same line (e.g. along a straight highway).
Convolution
A complete set of correlations, where every possible delay of the locally generated replica of the signal is included in the set.
Convolution Processor
A device that performs a convolution.
Correlation
A signal processing operation used to indicate when a received signal and a locally generated replica of the signal are correctly aligned.
Correlator
A hardware device that performs a correlation.
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dBm – Decibel with Respect to One Milliwatt
A measure of power, equal to ten times the logarithm (base ten) of the power in milliwatts. Power in dBm = power in dBW + 30.
dBW – Decibel with Respect to One Watt
A measure of power, equal to ten times the logarithm (base ten) of the power in watts. Power in dBW = power in dBm - 30.
dB-Hz – Decibel-Hertz
A log-ratio powers: equal to ten times the logarithm (base ten) of the ratio of signal power to the noise power in one Hertz of bandwidth. Power in dBm = power in dBW + 30.
Drive Test
A test of the performance of a wireless network, device, or service, performed from a vehicle traveling within the network area.
Doppler Shift
The apparent change in the frequency of a signal caused by the relative motion of the transmitter and receiver
DSP - Digital Signal Processing
A specialized microprocessor that performs Digital Signal Processing functions on a data stream. Used for improving the accuracy and reliability of digital communications. DSP works by clarifying, or standardizing, the levels or states of a digital signal. A DSP circuit is able to differentiate between human-made signals, which are orderly, and noise, which is inherently chaotic.
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E911 Phase II Mandate
A requirement issued by the US Federal Communications Commission for wireless service providers to offer location-fixing capabilities (also known as ALI Automatic Location Information) to support emergency '911' calling on their networks.
E-OTD - Enhanced Observed Time Difference
A positioning technology that uses the cellular signals themselves to determine location. It compares the difference between the time of arrival of the cellular signal at the handset, and at a nearby fixed receiver. Time differences from at least three non-colinear cell-towers are required to be able to compute position. When a position can be obtained, accuracy is of the order of 150m to 300m.
EDGE - Enhanced Data Rates for GSM Evolution
A technology that increases a network's efficiency, allowing transmissions speeds of up to 384 Kbps
E-OTD - Enhanced Observed Time Difference
A positioning technology that compares the differing times of arrival stations (on the handset versus a nearby fixed receiver) of signals transmitted by at least three base stations.
ETSI - European Telecommunication Standards Institute
A European organization corresponding to the Japanese ARIB under joint Japan-Europe activities related to WCDMA-DS, and plays a major role in 3G standardization efforts.
Ephemeris
A set of satellite orbit parameters used by GPS receivers to calculate the precise GPS satellite position and velocity. Ephemeris is used in the determination of the navigation solution and is periodically updated by the satellites to maintain its accuracy.
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FCC - Federal Communications Commission
The US government agency responsible for regulating telecommunications in the United States.
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GLL - Global Locate Library
The main portion of the Global Locate Driver Software that runs on the handset host processor. It contains functionality to handle assistance data, provide standards-based interfaces to the wireless network, manage chip communications and control, and compute position. It provides high-level commands for obtaining position fixes and performing continuous, mobile navigation. It interfaces to the hardware interface layer, which contains the platform-dependent code, enabling the GLL to remain 100% portable across platforms.
GMLC - Gateway Mobile Location Centre
Mobile Location network element defined by 3GPP standards. It acts as the gateway between the location infrastructure and the external world.
GPRS - General Packet Radio Service
A high-speed, packet-switched network that permits transmission speeds up to 171 Kbps. GPRS requires a specialized handset and gives users an 'always on' connection to the Internet
GPS
Global Positioning System -A worldwide navigation system owned and operated by the US government. GPS consists of a constellation of 24 active satellites that communicate with a ground control system and GPS receivers to provide accurate latitude, longitude, time and bearing 24 hours a day, worldwide.
GPS-Aiding
The process of providing additional remote processing or GPS satellite data to support a mobile device in fixing a location using GPS data.
GSM - Global Standard for Mobile Communications
A second generation digital cellular technology developed by European countries in the 1980's to facilitate pan-European roaming. GSM uses time division multiple access technology and operates at both cellular and PCS frequencies (900MHz, 1800MHz, 1900MHz). Other technologies used are CDMA, PDC & TDMA. In 1999, 66% of the world’s cell-phones were GSM (source: EMC World Cellular Database).
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Hz – Hertz
A measure of frequency, equal to one cycle per second.
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I&Q – In phase & Quadrature
Two channels in a GPS receiver, containing signals generated by down-converting with sine and cosine waveforms.
i-mode
A wireless service launched in Japan in spring 1999 by NTT DoCoMo. The service is accessed by a wireless packet network (PDC-P) and the contents are described in a subset of the HTML language.
IDEN - Integrated Digital Enhanced Network
A time division duplex--based wireless communication system developed by Motorola. The system features both voice and data communication as well as push-to-talk dispatch features. IDEN is used by Tier 1 Carrier in the US.
IF – Intermediate Frequency
A frequency below RF (Radio Frequency). In a GPS receiver, the RF chip converts the analog RF signal to IF and then converts it to a digital signal that is processed by the baseband chip.
IP Core
The 'intellectual property', usually a silicon design language code, that embodies an application or key capability for a device or integrated circuit. This portable code differs from an actual physical IC (chip) component purchased from a supplier to provide a similar capability.
IS-95/cdmaOne
A digital mobile telephony standard based on CDMA technology.
IS136 (TDMA)
See TDMA
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L1 Signal
The primary L-band signal transmitted by each GPS satellite at 1572.42 MHz. The L1 broadcast is modulated with the C/A and P-codes and with the navigation message
LCS - Location Services
An operator’s LCS infrastructure provides A-GPS functionality to the operator’s network.
LES/LBS - Location-enabled services
Location-based services. Applies to services provided to or in conjunction with the handset or mobile wireless device, where device location is intrinsic to the service.
LIF - Location Interoperability Forum
Formed by Ericsson, Motorola and Nokia in September 2000 with the mission to define, develop and promote common interfaces allowing interoperability between handsets and networks.
LMU - Location Measurement Unit
Network elements required to support some positioning methods. In cellular networks not synchronized to GPS time (GSM, TDMA, PDC, W-CDMA), LMUs have been proposed to provide precise timing signals to make A-GPS work. Global Locate’s IndoorGPS chips work on these networks, without LMUs, thanks to on-chip massive parallel correlation and Global Locate's patented navigation technologies.
LNA – Low Noise Amplifier
Analog radio amplifier, used as the first stage in a GPS front-end. The Global Locate, GL-LN22 RF chip contains an integrated LNA on-chip.
LTO - Long-term Orbits
Future satellite ephemeris, computed using Global Locate’s proprietary orbital models and field-proven. From this, future assistance data is generated for use in Enhanced Autonomous Mode.
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MS - Mobile Station
Refers to the handset or mobile wireless device in a C-plane architecture.
mW-s - Milliwatt-second
A measure of energy equal to one milliwatt of power for one second, also equal to one millijoule.
Massive Parallel Correlation
Performing many correlations at the same time. Traditional GPS receivers have two correlators per channel, and these correlators are used, sequentially, to search over the possible correlation delays to find the signal correlation peak. Massive parallel correlation, by contrast, uses up to 2046 correlators per channel, to search all possible correlation delays simultaneously.
Mobile Assisted Positioning
Any mobile centric positioning method (e.g. E-OTD, GPS) in which the MS (Mobile Station) provides position measurements to the network for computation of a location estimate by the network. The network may provide assistance data to the MS to enable position measurements and/or improve measurement performance.
Mobile Based Positioning
Any mobile centric positioning method (e.g. E-OTD, GPS) in which the MS (Mobile Station) performs both position measurements and computation of a location estimate and where assistance data useful or essential to one or both of these functions is provided to the MS by the network. Position methods where an MS performs measurements and location computation without network assistance data are not considered within this category.
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Navigation Data Bits
The data that is broadcast by the GPS satellites. This data contains information that tells GPS receivers the satellite locations, velocities, and clock offsets. The broadcast data rate is 50 bits per second.
Network Operators
The companies that own and operate the cellular networks. Also known as “Carriers”.
Non-colinear
Relating to cell-towers: towers are non-colinear if they do not lie along the same straight line.
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OTDOA - Observed Time Difference Of Arrival
Network based positioning method for UMTS in which the mobile measures the pilot signal time difference between three base stations. Similar to 2G E-OTD.
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PCF - Position Computation Function
The element of the wireless network infrastructure that contains the functionality needed to compute the position of the mobile device.
PCS - Personal Communications Services
Used to describe a newer class of wireless communications services recently authorized by the FCC (also known as high-band). PCS systems use a different radio frequency (the 1.x GHz band) than cellular phones, and generally use all-digital technology for transmission and reception.
PDA - Personal Digital Assistant
A hand-held mobile device used for data storage and recording. Also known as a Personal Information Manager, PIM. It can be equipped with applications such as calendars, notepads, address books and even e-mail and Internet access capabilities.
PDC - Personal Digital Cellular
A second-generation technology used in digital cellular telephone communication in Japan. It uses a variation of TDMA. Other technologies used are CDMA & GSM. In 1999, 12% off the world’s cell-phones were PDC (source: EMC World Cellular Database).
PDE - Position Determining Entity
Network element (specified in ANSI standards) responsible for providing A-GPS assistance data, and for computing positions of mobile phones.
PHS - Personal Handy Phone System
A digitalized evolution of the earlier analog cordless phone concept which enables outdoor use as well. PHS incorporates a unique Japanese standard which melds the advantages of the European DECT and CT2. The system operates in the 1.9 GHz band.
PN-code - Psuedo-Random Noise Code
A binary code (sequence of "1"s and "0"s) that exhibits noise-like properties in its power spectral density. Used in the GPS system to provide a unique binary code for each satellite's encoded signal.
Pseudoranges
Preliminary, uncorrected estimates of the distance from a receiver to a given GPS satellite.
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RF - Radio Frequency
Frequencies of the electromagnetic spectrum normally associated with transmission radio waves. Sometimes used to distinguish communication by wireless technologies, as opposed to transmission via wire.
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SLP- SUPL Location Platform
For U-plane architectures, the SUPL server is the counterpart to the SMLC in C-plane architectures. Manages LCS client requests, and interacts with the handset to obtain its location.
SMLC - Serving Mobile Location Centre
The SMLC is a network element defined by 3GPP (ETSI) standards. It manages the overall coordination and scheduling of resources to perform positioning of a mobile phone.
SMS - Short Message Service
Allows the transmission of messages up to 160 alphanumeric characters to be sent to or from a GSM device. Also referred to as text messaging.
SNR - Signal-to-Noise Ratio
A measure of the ratio of signal power versus noise power usually expressed in dB. Lower ratios mean there is more noise relative to signal.
SUPL - Secure User Plane Location
Standards for using U-plane architecture to implement LCS infrastructure.
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TCXO - Temperature Compensated Crystal Oscillator
Provides accurate frequency reference in mobile wireless devices.
TDMA - Time Division Multiple Access (IS 136)
A second-generation digital communication technology that divides a conversation into digital packets and time-shares it with other conversations on the same channel. TDMA provides a threefold increase in system capacity over AMPS. Other technologies used are CDMA , GSM, & PDC. IS136 is the TDMA standard first established in the USA. In 1999, 9% of the world’s cell-phones were TDMA (IS136) (source: EMC World Cellular Database).
TOA - Time of Arrival
Network based positioning method that measures the time it takes for radio signals to arrive at multiple points.
TR45
Committee that operates under the guidelines of the Telecommunications Industry Association. TR-45 deals specifically with issues relating to performance, compatibility, inter-operability and service standards for mobile and personal communications systems.
TTFF - Time-to-first-fix
The time required for the A-GPS receiver to perform its first location fix. This usually applies to the push-to-fix request made for E911/E112 or LES/LBS applications. For mobile navigation, it usually refers to the starting position fix.
Thin Client
In client-server systems, a client that requires only minimal hardware / software resources to communicate with the server and perform its designed tasks.
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U-Plane - User Plane
Refers to the LCS architecture and method of using a data bearer (eg, GPRS) to provide assistance data to the handset and return location responses from the handset. Because the location data is not directly associated with the voice call, U-plane is not used for E911/E112 services, but is instead used for LES/LBS applications.
UE - User Equipment
Refers to the handset or mobile wireless device in a SUPL-based system.
UMTS - Universal Mobile Telecommunications System
The third generation mobile standards that will build on the success of GSM/GPRS and on the GSM operators' existing investment in infrastructure. Data rates offered will be up to 2 million bits per second.
UTC - Universal Time Coordinated
An international, highly accurate and stable uniform atomic time system kept very close, by offsets, to the universal time corrected for seasonal variations in the earth's rotation rate. Maintained by the U.S. Naval Observatory. GPS time is directly relatable to UTC: UTC-GPS = seconds. (The changing constant = 13 seconds in 2001.)
UTRAN - UMTS Terrestrial Radio Access Network
A conceptual term identifying that part of the network which consists of Radio Network Controllers and Node Base stations.
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VCO – Voltage Controlled Oscillator
An oscillator with frequency output proportional to a control voltage. This component is commonly used in cellular handsets.
VPN - Virtual Private Network
Using encryption and other security methods, a network that prevents information from being intercepted and guarantees that only authorized users can access the network.
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W-CDMA - Wideband Code Division Multiple Access
Radio access technology used in UMTS/3G. 3GPP is the standardization body for W-CDMA.
WAP - Wireless Application Protocol
A technology designed to provide users of mobile terminal with rapid and efficient access to the Internet.
WGS-84 - World Geodetic System 1984
The mathematical ellipsoid used by GPS since January, 1987.
WWRN - Worldwide Reference Network™
The Global Locate network of reference stations that, together with data processing hubs, provide the GPS satellite orbits.
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Precision Fleet