Standard Horizon, Standard Horizon
GPS, Standard Horizon Chartplotters, Standard Horizon CPV350, Standard Horizon
VHF, Standard Horizon Quantum, Standard Horizon HX370, Standard Horizon Loud
Hailer, Standard Horizon FF520, Standard Horizon Black Box, Standard Horizon
Fishfinder, Standard Horizon HX471, Standard Horizon Matrix, Standard Horizon
Quest-X, Standard Horizon Handheld VHF, Standard Horizon HX270S, Standard
Horizon Transducers, Standard Horizon Voice Scrambler
For
prices and ordering please search for the product part numbers you want from
my new website www.davesmarineelectronics.com
GPS Glossary Terms
written by Michael Burch
2D Operating Mode -- A two-dimensional GPS position fix that includes only horizontal coordinates (no GPS elevation). It requires a minimum of three visible satellites.
3D Operating Mode -- A three-dimensional GPS position fix that includes horizontal coordinates, plus elevation. It requires a minimum of four visible satellites.
Accuracy -- How close a fix comes to the actual position.
Acquisition -- The ability to find and lock on to satellite signals for ranging.
Acquisition Time -- The time it takes a GPS receiver to acquire satellite signals and determine the initial position.
Active Antenna -- An antenna that amplifies the GPS signal before sending it to the receiver.
Active Leg -- The segment of a route currently being traveled. A "segment" is that portion of a route between any two waypoints in the route.
Almanac -- A set of parameters included in the GPS satellite navigation message that a receiver uses to predict the approximate location of a satellite. The almanac contains information about all of the satellites in the constellation.
Altimeter -- An instrument for determining elevation, especially an aneroid barometer used in aircraft that senses pressure changes accompanying changes in altitude.
Ambiguity -- The initial bias in a carrier-phase observation of an arbitrary number of cycles. The initial phase measurement made when a GPS receiver first locks onto a GPS signal is ambiguous by an integer number of cycles because the receiver has no way of knowing the exact number of carrier wave cycles between the satellite and the receiver. This ambiguity, which remains constant as long as the receiver remains locked on the signal, is established when the carrier-phase data are processed.
Anywhere Fix -- The ability of a receiver to start position calculations without being given an approximate location and time.
Atomic Clock -- A very precise clock that operates using the elements cesium or rubidium. A cesium clock has an error of one second per million years. GPS satellites contain multiple cesium and rubidium clocks.
Bearing -- The angle between two different points on the earth's surface with respect to true north.
Cartography -- The art or technique of making maps or charts. Many GPS receivers have detailed mapping-or cartography-capabilities.
Channel -- In a receiver, a path for an electronic signal that is reserved for a specific satellite and used for various functions.
Clock Aiding -- An accuracy enhancement technique in which an additional atomic clock (rubidium) provides accurate time to the receiver for calculating satellite clock frequency, phase bias, and clock drift.
Clock Bias -- The difference between the indicated clock time in the GPS receiver and true universal time (or GPS satellite time).
Clock Offset -- A constant difference in the time reading between two clocks, normally used to indicate a difference between two time zones.
Code-Tracking Loop -- A module in a GPS receiver used to align a PRN code sequence present in a signal coming from a satellite with an identical PRN code sequence generated within the receiver. Alignment is achieved by appropriately shifting the receiver-generated code chips in time so that a particular chip in the sequence is generated at the same instant its twin arrives.
Cold Start -- The ability of a GPS receiver to start providing position updates without the assistance of any almanac information stored in its memory.
Course -- The direction from the beginning landmark of a course to its destination (measured in degrees, radians, or mils), or the direction from a route waypoint to the next waypoint in the route segment.
Course Up Orientation -- Fixes the GPS receiver's map display so the direction of navigation is always "up."
Data Message -- A message included in the GPS signal that reports the satellite location, clock corrections, and health. Included is approximate information about the other satellites in the system as well.
Datum -- The coordinate system used to define position on the earth's surface.
Dead Reckoning -- The technique of determining position by computing distance traveled on a given course. Distance traveled is determined by multiplying speed by elapsed time.
Desired Track (DTK) -- The compass course between the "from" and "to" waypoints.
Dithering -- Introducing errors into the satellite clock readout on GPS signals for the purpose of degrading GPS position accuracy for civil users.
Distance -- The length (in feet, meters, miles, etc.) between two waypoints or from your current position to a destination waypoint. This length can be measured in straight-line (rhumb line) or great-circle (over the earth) terms. GPS normally uses great circle calculations for distance and desired track.
Doppler Effect -- The shift in the frequency of a received radio signal due to the relative motion of the transmitter and receiver.
Doppler Shift -- The apparent change in the frequency of a signal caused by the relative motion of the signal source (transmitter) and receiver.
Elevation -- The distance above or below mean sea level.
Estimated Time Of Arrival (ETA) -- The estimated time you will arrive at a destination.
Fix -- Defining position, where two lines such as latitude and longitude cross, as determined by one or more navigation aids or techniques.
Frequency -- The number of waves passing a specific point within a unit period of time, expressed in Hertz (cycles per second).
Geocaching -- A high-tech version of hide-and-seek. Geocachers seek out hidden treasures utilizing GPS coordinates posted on the Internet by those hiding the cache.
Geostationary Satellites -- Those satellites situated in a constant orbit position relative to a given area of the globe with the purpose of maintaining constant coverage of that area.
Global Positioning System(GPS) -- A global navigation system based on 24 or more satellites orbiting the earth at an altitude of 12,000 statue miles and providing very precise, worldwide positioning and navigation information 24 hours a day, in any weather. Also called the NAVSTAR system.
GoTo -- A route consisting of one leg, with your present position being the start of the route and a single defined waypoint as the destination.
Greenwich Mean Time (GMT) -- The mean solar time for Greenwich, England, which is located on the Prime Meridian (zero longitude). Based on the rotation of the earth, GMT is used as the basis for calculating standard time throughout most of the world.
Grid -- A pattern of regularly spaced horizontal and vertical lines forming square zones on a map used as a reference for establishing points. Grid examples are UTM, MGRS, and Maidenhead.
GPS Week -- The number of elapsed weeks (modulo 1024) since the week beginning January 6, 1980. The week number sequentially increments at Saturday/Sunday midnight in GPS (system) Time.
Heading -- The direction in which a vehicle is moving. For air and sea operations, this may differ from actual Course Over Ground (COG) due to winds, currents, etc.
Inclination -- One of the orbital parameters that describes the orientation of an orbit. It is the angle between the orbital plane and a reference plane, the plane of the celestial equator for geocentric orbits and the ecliptic for heliocentric orbits.
Invert Route -- To display and navigate a route from end to beginning for purposes of returning to the route's starting point.
Latitude -- The distance north or south of the equator as measured in degrees, with 1 degree of latitude equaling 60 nautical miles and 1 minute of latitude being 1 nautical mile. Latitude is constant on a parallel. One must distinguish between astronomical and geodetic (for example, World Geodetic System of 1984 [WGS 84]) latitude.
Leg (Route) -- A portion of a route consisting of a starting (from) waypoint and a destination (to) waypoint. A route that is comprised of waypoints A, B, C, and D would contain three legs. The route legs would be from A to B, from B to C, and from C to D.
Longitude -- The distance east or west from the prime meridian
as measured in degrees, with each degree becoming smaller the closer it comes to either of the poles. At the equator, 1 degree of longitude equals 60 nautical miles. Along a meridian, the longitude is constant. One must distinguish between astronomical and geodetic (for example, World Geodetic System of 1984 [WGS 84]) longitude.
Loran-C -- Long range navigation system that determines position by comparing the arrival times of radio signals with two or more master/secondary station pairs.
Liquid Crystal Display (LCD) -- A display circuit characterized by a liquid crystal element sandwiched between two glass panels. Characters are produced by applying an electric field to liquid crystal molecules and arranging them to act as light filters.
Mean Sea Level -- The average level of the ocean's surface, as measured by the level halfway between mean high and low tide. Used as a standard in determining land elevation or sea depths.
Magnetic Deviation -- The error in a magnetic compass reading caused by the difference between the true north pole and the magnetic north pole, also referred to as magnetic variation.
Magnetic North -- Represents the direction of the north magnetic pole from the observer's position. The direction a compass points.
Magnetic Variation -- In navigation, at a given place and time, the horizontal angle (or difference) between true north and magnetic north. Magnetic variation is measured east or west of true north.
Megahertz (MHz) -- A radio signal of one-million cycles.
Multiplexing Receiver -- A GPS receiver that switches at a very rapid rate between satellites being tracked. Typically, multiplexing receivers require more time for satellite acquisition and are not as accurate as parallel channel receivers. Multiplexing receivers are also more prone to lose a satellite fix in dense woods than parallel channel GPS receivers.
Nautical Mile -- A unit of length used in sea and air navigation, based on the length of one minute of arc of a great circle, especially an international and U.S. unit equal to 1,852 meters (about 6,076 feet).
Navigation -- The act of determining the course or heading of movement. This movement could be for a plane, ship, automobile, person on foot, or any other similar means.
NAVSTAR -- The official U.S. Government name given to the GPS satellite system. NAVSTAR is an acronym for NAVigation Satellite Timing And Ranging.
Parallel Channel Receiver -- A continuous tracking receiver using multiple receiver circuits to track more than one satellite simultaneously.
Phase Differencing -- The technique of using different GPS receivers at different locations to measure the phase angles of the carrier signal from the same satellite. These angles are compared by a communications link between the two locations if real-time operations are required.
Pixel -- A single display element on an LCD screen. The more pixels, the higher the resolution and definition.
Position -- An exact, unique location based on a geographic coordinate system.
Position Fix -- The GPS receiver's computed position coordinates.
Position Format -- The way in which the GPS receiver's position will be displayed on the screen. Commonly displayed as latitude/longitude in degrees and minutes, with options for degrees, minutes and seconds, degrees only, or one of several grid formats.
Prime Meridian -- The zero meridian, used as a reference line from which longitude east and west is measured. It passes through Greenwich, England.
Ranging -- A technique used to determine a line of position by calculating the distance between a receiver and a known reference point.
Receiver Autonomous Integrity Monitoring (RAIM) -- A technique by which a GPS receiver system detects incorrect satellite signals by comparing solutions with different sets of satellites.
Relative Accuracy -- The accuracy with which a user can measure position relative to that of another user on the same navigation system at the same time.
Reliability -- The ability to perform a specific function without failure under specified conditions for a given length of time.
Route -- A group of waypoints entered into the GPS receiver in the sequence you desire to navigate them.
Speed Over Ground (SOG) -- The actual speed the GPS unit is moving over the ground. This may differ from airspeed or nautical speed due to such things as head winds or sea conditions. For example, a plane that is going 120 knots into a 10-knot head wind will have a SOG of 110 knots.
Track -- Your current direction of travel relative to a ground position (same as Course Over Ground).
Track Up Orientation -- Fixes the GPS receiver's map display so the current track heading is at the top of the screen.
Triangulation -- A method of determining the location of an unknown point, as in GPS navigation, by using the laws of plane trigonometry.
True North -- The direction of the North Pole from your current position. Magnetic compasses indicate north differently due to the variation between true north and magnetic north. A GPS receiver can display headings referenced to true north or magnetic north.
User Interface -- The way in which information is exchanged between the GPS receiver and the user. This takes place through the screen display and buttons on the unit.
Warm Start -- The ability of a GPS receiver to begin navigating using almanac information stored in its memory from previous use.
Waypoint -- A destination. The coordinates of locations along the desired path as measured in geographic coordinates of longitude and latitude.
Wide Area Augmentation System (WAAS) -- A system that enhances the GPS SPS and is available over a wide geographical area. The WAAS being developed by the Federal Aviation Administration, in concert with other agencies.
