Global Navigation Satellite System (GNSS) receivers, using the GPS, GLONASS, or Beidou system, are used in many applications. Global Navigation Satellite System (GNSS is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage Basic concept of GPS operation A GPS receiver calculates its position by carefully timing the signals sent by the constellation of GPS Satellites high above the Earth Beidou Navigation System ( or Beidou Satellite Navigation and Positioning System ( is a project by China to develop an independent Satellite navigation

Navigation

• Automobiles can be equipped with GNSS receivers at the factory or as aftermarket equipment. The automotive aftermarket is the part of the automotive industry concerned with the Manufacturing, Remanufacturing, Distribution, Retailing, Units often display moving maps and information about location, speed, direction, and nearby streets and points of interest. A point of interest, or POI, is a specific point location that someone may find useful or interesting

Main article: Automotive navigation system

A GPS receiver in civilian automobile use. An automotive navigation system is a satellite navigation system designed for use in Automobiles.

• Aircraft navigation systems usually display a "moving map" and are often connected to the autopilot for en-route navigation. An autopilot is a mechanical electrical or hydraulic system used to guide a vehicle without assistance from a human being Cockpit-mounted GNSS receivers and glass cockpits are appearing in general aviation aircraft of all sizes, using technologies such as WAAS or LAAS to increase accuracy. A glass cockpit is an Aircraft cockpit that features electronic instrument displays. General aviation (abbr GA) is one of two categories of Civil aviation. WAAS Objectives Accuracy The WAAS specification requires it to provide a position accuracy of 7 The Local Area Augmentation System (LAAS is an all-weather aircraft landing system based on real-time differential correction of the GPS signal Many of these systems may be certified for instrument flight rules navigation, and some can also be used for final approach and landing operations. Glider pilots use GNSS Flight Recorders to log GNSS data verifying their arrival at turn points in gliding competitions. Terminology A "glider" is an unpowered Aircraft. The most common types of glider are today used for sporting purposes The International Gliding Commission (IGC is the international governing body for the sport of Gliding. Some of the pilots in the sport of Gliding take part in gliding competitions. Flight computers installed in many gliders also use GNSS to compute wind speed aloft, and glide paths to waypoints such as alternate airports or mountain passes, to aid en route decision making for cross-country soaring. A waypoint is a reference point in physical space used for purposes of Navigation.

• Boats and ships can use GNSS to navigate all of the world's lakes, seas and oceans. A boat is a Watercraft of modest size designed to float or plane on water and provide transport over it A ship /ʃɪp/ is a large vessel that floats on water Ships are generally distinguished from Boats based on size Maritime GNSS units include functions useful on water, such as “man overboard” (MOB) functions that allow instantly marking the location where a person has fallen overboard, which simplifies rescue efforts. GNSS may be connected to the ships self-steering gear and Chartplotters using the NMEA 0183 interface. Self-steering gear is equipment used on ships and boats to maintain a chosen course without constant human action A Chartplotter is a device used in marine Navigation that integrates GPS data with an electronic navigational chart (ENC. NMEA 0183 (or NMEA for short is a combined electrical and data specification for communication between marine electronic devices such as Echo sounder, sonars GNSS can also improve the security of shipping traffic by enabling AIS. The Automatic Identification System ( AIS) is a System used by ships and Vessel Traffic Services (VTS principally for identification and locating vessels

A GPS unit showing basic way point and tracking information which is typically required for outdoor sport and recreational use

• Heavy Equipment can use GNSS in construction, mining and precision agriculture. Precision farming or precision agriculture is an agricultural concept relying on the existence of in-field variability. The blades and buckets of construction equipment are controlled automatically in GNSS-based machine guidance systems. The term Machine Guidance is used to describe a wide range of techniques which improve the productivity of agricultural mining and construction equipment Agricultural equipment may use GNSS to steer automatically, or as a visual aid displayed on a screen for the driver. Agricultural machinery is any kind of Machinery used on a Farm to help with Farming. This is very useful for controlled traffic and row crop operations and when spraying. Harvesters with yield monitors can also use GNSS to create a yield map of the paddock being harvested.

• Bicycles often use GNSS in racing and touring. Cycling is the use of Bicycles or - less commonly - Unicycles Tricycles Quadricycles and other similar wheeled Human powered vehicles GNSS navigation allows cyclists to plot their course in advance and follow this course, which may include quieter, narrower streets, without having to stop frequently to refer to separate maps. Some GNSS receivers are specifically adapted for cycling with special mounts and housings.

• Hikers, climbers, and even ordinary pedestrians in urban or rural environments can use GNSS to determine their position, with or without reference to separate maps. The word 'hiking' is understood in all English-speaking countries but there are differences in usage “Alpinist” redirects here See also Alpinist (magazine Mountaineering is the Sport, Hobby or Profession of In isolated areas, the ability of GNSS to provide a precise position can greatly enhance the chances of rescue when climbers or hikers are disabled or lost (if they have a means of communication with rescue workers).

• GNSS equipment for the visually impaired is available. There have been many attempts at integrating Global Positioning System into a navigation-assistance system for the blind.

• Spacecraft are now beginning to use GNSS as a navigational tool. A spacecraft is a Vehicle or machine designed for Spaceflight. The addition of a GNSS receiver to a spacecraft allows precise orbit determination without ground tracking. This, in turn, enables autonomous spacecraft navigation, formation flying, and autonomous rendezvous. The use of GNSS in MEO, GEO, HEO, and highly elliptical orbits is feasible only if the receiver can acquire and track the much weaker (15 - 20 dB) GNSS side-lobe signals. This design constraint, and the radiation environment found in space, prevents the use of COTS receivers. Low earth orbit satellite constellations such as the one operated by Orbcomm uses GPS receivers on all satellites^[1]

Surveying and mapping

• Surveying — Survey-Grade GNSS receivers can be used to position survey markers, buildings, and road construction. A Low Earth Orbit (LEO is generally defined as an Orbit within the locus extending from the Earth’s surface up to an altitude of 2000 km ORBCOMM ( is a company that offers M2M global asset monitoring and messaging services from its constellation of 29 LEO Communications satellites Surveying is the technique and science of accurately determining the terrestrial or three-dimensional space Position of points and the distances and angles between Survey markers, or survey monuments, are objects placed to mark key survey points on the earth's surface A road is an identifiable route, way or path between two or more places. These units use the signal from both the L1 and L2 GPS frequencies. Even though the L2 code data are encrypted, the signal's carrier wave enables correction of some ionospheric errors. In Telecommunications, a carrier wave, or carrier is a Waveform (usually Sinusoidal) that is modulated (modified with an input signal The ionosphere is the uppermost part of the atmosphere, distinguished because it is Ionized by solar radiation These dual-frequency GPS receivers typically cost US$10,000 or more, but can have positioning errors on the order of one centimeter or less when used in carrier phase differential GPS mode. Differential Global Positioning System (DGPS is an enhancement to Global Positioning System that uses a network of fixed ground-based reference stations to broadcast the difference

• Mapping and geographic information systems (GIS) — Most mapping grade GNSS receivers use the carrier wave data from only the L1 frequency, but have a precise crystal oscillator which reduces errors related to receiver clock jitter. A crystal oscillator is an Electronic circuit that uses the mechanical Resonance of a vibrating Crystal of piezoelectric material to create an Jitter is an unwanted variation of one or more characteristics of a periodic signal in Electronics and Telecommunications. This allows positioning errors on the order of one meter or less in real-time, with a differential GNSS signal received using a separate radio receiver. By storing the carrier phase measurements and differentially post-processing the data, positioning errors on the order of 10 centimeters are possible with these receivers. Post-processing is used in Differential GPS to obtain precise positions of unknown points by relating them to known points such as Survey markers Differential
  • Several projects, including OpenStreetMap and TierraWiki, allow users to create maps collaboratively, much like a wiki, using consumer-grade GPS receivers. OpenStreetMap ( OSM) is a collaborative project to create a free editable Map of the world A wiki is a page or collection of Web pages designed to enable anyone who accesses it to contribute or modify content using a simplified Markup language.

• Geophysics and geology — High precision measurements of crustal strain can be made with differential GNSS by finding the relative displacement between GNSS sensors. In Geology, a crust is the outermost solid shell of a planet or moon Multiple stations situated around an actively deforming area (such as a volcano or fault zone) can be used to find strain and ground movement. Plate tectonics and hotspots Divergent plate boundaries At the In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement These measurements can then be used to interpret the cause of the deformation, such as a dike or sill beneath the surface of an active volcano. Deformation monitoring (also referred to as Deformation survey) is the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result

• Archeology — As archaeologists excavate a site, they generally make a three-dimensional map of the site, detailing where each artifact is found. Archaeology, archeology, or archæology (from Greek grc ἀρχαιολογία archaiologia – grc ἀρχαῖος archaīos

Other uses

• Precise time reference — Many systems that must be accurately synchronized use GNSS as a source of accurate time. GNSS can be used as a reference clock for time code generators or Network Time Protocol (NTP) time servers. A radio clock is a Clock that is Synchronized by a Time code bit stream transmitted by a Radio transmitter connected to a Time standard The Network Time Protocol ( NTP) is a protocol for distributing the Coordinated Universal Time (UTC by means of synchronizing the clocks of computer systems A time server is a server Computer that reads the actual time from a reference clock and distributes this information to its clients using a Computer network Sensors (for seismology or other monitoring application), can use GNSS as a precise time source, so events may be timed accurately. A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument Seismology (from Greek grc σεισμός seismos, "earthquake" and grc -λογία -logia) is the scientific study of Earthquakes Time division multiple access (TDMA) communications networks often rely on this precise timing to synchronize RF generating equipment, network equipment, and multiplexers. This article is about the medium access technology The name "TDMA" is also commonly used in the United States to refer to D-AMPS, which is a mobile telephone In Electronics, a multiplexer or mux ( occasionally the term muldex is also found for a combination multiplexer-demultiplexer

• Mobile Satellite Communications — Satellite communications systems use a directional antenna (usually a "dish") pointed at a satellite. The antenna on a moving ship or train, for example, must be pointed based on its current location. Modern antenna controllers usually incorporate a GNSS receiver to provide this information.

• Emergency and Location-based services — GNSS functionality can be used by emergency services to locate cell phones. Enhanced 9-1-1 or E9-1-1 service is a North American telecommunications based system that automatically associates a physical address with the calling party's telephone A location-based service (LBS is an information and entertainment service accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical Emergency services are organizations which ensure Public safety by addressing different emergencies The ability to locate a mobile phone is required in the United States by E911 emergency services legislation. Enhanced 9-1-1 or E9-1-1 service is a North American telecommunications based system that automatically associates a physical address with the calling party's telephone However, as of September 2006 such a system is not in place in all parts of the country. GNSS is less dependent on the telecommunications network topology than radiolocation for compatible phones. Topology ( Greek topos, "place" and logos, "study" is the branch of Mathematics that studies the properties of Radiolocation is the process of finding the location of something through the use of Radio waves It generally refers to passive uses particularly Radar Assisted GPS reduces the power requirements of the mobile phone and increases the accuracy of the location. Assisted GPS, generally abbreviated as A-GPS, enhances the startup performance of a GPS satellite-based positioning system A phone's geographic location may also be used to provide location-based services including advertising, or other location-specific information.

• Location-based games — The availability of hand-held GNSS receivers has led to games such as Geocaching, which involves using a hand-held GNSS unit to travel to a specific longitude and latitude to search for objects hidden by other geocachers. A location-based game (or location-enabled game) is one in which the Game play somehow evolves and progresses via a player's location Geocaching is an outdoor treasure-hunting game in which the participants use a Global Positioning System (GPS receiver or other navigational techniques Longitude (ˈlɒndʒɪˌtjuːd or ˈlɒŋgɪˌtjuːd symbolized by the Greek character Lambda (λ is the east-west Geographic coordinate measurement Latitude, usually denoted symbolically by the Greek letter phi ( Φ) gives the location of a place on Earth (or other planetary body north or south of the This popular activity often includes walking or hiking to natural locations. Geodashing is an outdoor sport using waypoints. Geodashing is an outdoor Sport in which teams of players use GPS receivers to find and visit randomly-selected "dashpoints" (also called "waypoints" A waypoint is a reference point in physical space used for purposes of Navigation.

• Aircraft passengers — Most airlines allow passenger use of GNSS units on their flights, except during landing and take-off when other electronic devices are also restricted. An airline provides air transport services for Passengers or Freight, generally with a recognized operating certificate or license Even though consumer GNSS receivers have a minimal risk of interference, a few airlines disallow use of hand-held receivers during flight. Other airlines integrate aircraft tracking into the seat-back television entertainment system, available to all passengers even during takeoff and landing. ^[2]

• Heading information — The GNSS system can be used to determine heading information, even though it was not designed for this purpose. A "GNSS compass" uses a pair of antennas separated by about 50 cm to detect the phase difference in the carrier signal from a particular GNSS satellite. ^[3] Given the positions of the satellite, the position of the antenna, and the phase difference, the orientation of the two antennas can be computed. More expensive GNSS compass systems use three antennas in a triangle to get three separate readings with respect to each satellite. A GNSS compass is not subject to magnetic declination as a magnetic compass is, and doesn't need to be reset periodically like a gyrocompass. The magnetic declination (also known as grid magnetic angle in military circles at any point on the Earth is the angle between the local magnetic field -- the direction A gyrocompass is similar to a Gyroscope. It is a Compass that finds True north by using an (electrically powered fast-spinning wheel and friction It is, however, subject to multipath effects.

• GPS tracking systems use GNSS to determine the location of a vehicle, person, pet or freight, and to record the position at regular intervals in order to create a log of movements. A GPS tracking unit is a device that uses the Global Positioning System to determine the precise location of a vehicle person or other asset to which it is attached and The data can be stored inside the unit, or sent to a remote computer by radio or cellular modem. Some systems allow the location to be viewed in real-time on the Internet with a web-browser.

• Recent innovations in GPS tracking technology include its use for monitoring the whereabouts of convicted sex offenders, using GPS devices on their ankles as a condition of their parole. This passive monitoring system allows law enforcement officials to review the daily movements of offenders for a cost of only $5 or $10 per day. Real time, or instant tracking is considered too costly for GPS tracking of criminals. (cited from [2]).

• Weather Prediction Improvements — Measurement of atmospheric bending of GNSS satellite signals by specialized GNSS receivers in orbital satellites can be used to determine atmospheric conditions such as air density, temperature, moisture and electron density. Such information from a set of six micro-satellites, launched in April 2006, called the Constellation of Observing System for Meteorology, Ionosphere and Climate COSMIC has been proven to improve the accuracy of weather prediction models. COSMIC is also a code name used to label NATO classified information.

• Photographic Geocoding — Combining GNSS position data with photographs taken with a (typically digital) camera, allows one to view the photographs on a map or to lookup the locations where they were taken in a gazeteer. A geocoded photograph is a Photograph which is associated with a geographical location A photograph (often shortened to photo) is an Image created by Light falling on a light-sensitive surface usually Photographic film or an electronic A camera is a device used to capture images either as still Photographs or as sequences of moving images ( Movies or Videos. A gazetteer is a geographical Dictionary or directory, an important reference for information about places and place names (see Toponomy) used in conjunction It's possible to automatically annotate the photographs with the location they depict by integrating a GNSS device into the camera so that co-ordinates are embedded into photographs as Exif metadata. Exchangeable image file format ( Exif) is a specification for the Image File format used by Digital cameras The specification uses the existing Metadata ( meta data, or sometimes metainformation) is "data about data" of any sort in any media Alternatively, the timestamps of pictures can be correlated with a GNSS track log. ^[4][5]

• Skydiving — Most commercial drop zones use a GNSS to aid the pilot to "spot" the plane to the correct position relative to the dropzone that will allow all skydivers on the load to be able to fly their canopies back to the landing area. Parachuting, also known as skydiving is where a person jumps from enough height so that he can deploy a fabric Parachute and land safely The "spot" takes into account the number of groups exiting the plane and the upper winds. In areas where skydiving through cloud is permitted the GNSS can be the sole visual indicator when spotting in overcast conditions, this is referred to as a "GPS Spot".

• Marketing — Some market research companies have combined GIS systems and survey based research to help companies to decide where to open new branches, and to target their advertising according to the usage patterns of roads and the socio-demographic attributes of residential zones. In popular usage "marketing" is the promotion of products especially Advertising and Branding However in professional usage the term has a wider meaning of

• Wreck diving — A popular variant of scuba diving is known as wreck diving. Wreck diving is a type of Recreational diving where Shipwrecks are explored In order to locate the desired shipwreck on the bottom of the ocean floor GPS is used to navigate to the approximate location and then the shipwreck is found using an echosounder. A shipwreck can refer to a wrecked ship or to the event that caused the wreck such as the striking of something that causes the ship to sink the stranding of the ship on rocks Sonar (which started as an Acronym for sound navigation and ranging) is a technique that uses Sound propagation (usually underwater to navigate

• Social Networking A growing number of companies are marketing cellular phones equipped with GPS technology, offering the ability to pinpoint friends on custom created maps, along with alerts that inform the user when the party is within a programmed range. Not only do many of these phones offer social networking functions, they offer standard GPS navigation features such as audible voice commands for in-vehicle GPS navigation. (cited from [3])

References