- B – current latitude;当前纬度
- L –current longitude;当前经度
- H – current altitude;当前海拔（高程）
- rms2D – expected planar RMS,m;平面RMS（平方根误差）
- HDOP – current Horizontal Delusion of Precision;当前水平精度因子
- VDOP – current Vertical Delusion of Precision;当前垂直(高程)精度因子
- GPS – a number of GPSs atellites used in calculating position solution;
- GLN – a number of GLONASS satellites used in calculating position solution;
- UTC – current UTC time;
- Date – current date;
- Status – solution status (OLD– no solution, 2D – 2D solution, 3D – 3D solution,
- DIFF – differential augmentations were used, CORR – forming differential augmentations)
- B – averaged latitude;平均纬度;
- L – averaged longitude;平均经度
- H – averaged altitude;平均高程
- rms2D – planar RMS, calculated over position statistics, m 平面RMS（平方根误差）
- rmsH – altitude RMS,calculated over position statistics;高程RMS（平方根误差）
- rmsV – speed RMS, calculated over position statistics, m;速度RMS（平方根误差）
- Nall – a number of solutionsin statistics;解算计数
- N – a number of solution over which the average coordinates are averaged平均坐标求平均解算次数(always less or equal than Nall);
- MaxHDOP (user defined) – a maximal possible HDOP for a solution to be included in statistics;纳入统计的最大水平精度因子
- MaxVDOP (user defined) – a maximal possible VDOP for a solution to be included in statistics;纳入统计的最大垂直精度因子
- DIFF only – only the solutionthat used differential augmentations are included in statistics.只统计差分增强系统
- Bfix (user defined) – chart’s centre’s reference latitude; 基准纬度
- Lfix (user defined) – chart’s centre’s reference longitude;基准经度
- Hfix (user defined in the PROFILE window)– reference altitude;参考高程
- Rs – chart’s inner ring radius;图表的内圈半径
- dX – current coordinates planar deviation from the reference coordinates;相对于基准坐标当前坐标平面偏差
- dMx – planar averaged coordinates deviation from the reference coordinates;相对于基准坐标平均平面偏差
- dH – current altitude deviation from the reference altitude;相对于基准高程当前高程面偏差
- dHx – averaged altitude deviation from the reference altitude;相对于基准高程当前高程偏差平均
- Set Statistic – set Bfix and Lfix to the averaged coordinates;设置平均坐标
- Set Current – set Bfix and Lfix to the current coordinates.设置当前坐标
2-D GPS mode A procedure of determining a2-D position using signals received from
the best (or only) three available GPSsatellites. Altitude is assumed tobe known and constant. A 2-D positionsolution will only be determinedif signals from three or more satellitesare available.
2 dRMS Twice the distance root meansquared. The error distance within which95% of the position solutions will fall.
2-D Two Dimensional. A 2-D position isdefined as latitude, longitude, andaltitude.
3-D Three Dimensional. A 3-D position isdefined as latitude, longitude, andaltitude.
3-D GPS mode A procedure of determining a3-D position using signals received from
the best (or only) four available GPSsatellites. A 3-D position solutionwill only be determined if signals fromfour or more satellites are available.
Almanac历书 A reduced-precision subset子集of theephemeris星历 parameters. Used by thereceiver to compute the elevation angle仰角, azimuthangle方位角, and estimatedDoppler of the satellites. Each satellitebroadcasts the almanac for allthe satellites in the system.
ASCII American Standard Code forInformation Interchange. A standard set of128 characters, symbols and control codesused for computercommunications. ASCII characters require 7bits of data to send, but areoften sent 8 bits at a time with the extrabit being a zero.
Asynchronous communication A method of sending data in which the bitscan be sent at random times.Data transmission is not synchronized to aclock. With asynchronoustransmission, each character is transmittedone at a time with a “start”bit at the beginning and one or more “stop”bits at the end. Any amountof time can elapse before the nextcharacter is sent.
auto GPS mode A procedure of automaticallydetermining either a 2-D or 3-D positionusing signals received from GPS satellites.The solution automaticallytransitions between 2-D and 3-D dependingon the number of satellitesavailable, the PDOP of the availablesatellites, and the defined PDOPswitch value. (See PDOP and PDOPconstellation switch).
azimuth angle The angle of the line-of-sitevector, projected on the horizontal plane,
measured clockwise from true North.
bandwidth The range of frequencies occupied bya signal. Also, the informationcarrying capability of a communication channelor line.
baud A measure of the speed of datatransmission. Baud and bit rate are thesame for direct equipment interconnections(e.g., via RS-232). Baud andbit rate are not the same for modulated datalinks, whether wire or radio.
bit Binary digit. The smallest unit ofinformation into which digital datacan be subdivided and which a computer canhold. Each bit has onlytwo values (e.g., on/off, one/zero,true/false).
bit rate The rate at which bits are transmittedover a communication path.Normally expressed in bits per second (bps).
byte A set of contiguous bits that make up adiscrete item of information. A
byte usually consists of a series of 8 bits,and represents one character.
C/A code The Coarse/Acquisition code. This isthe civilian code made availableby the Department of Defense. It is subject toselective availability(SA). Users can reduce the effects of SA byusing differential GPS.
carrier The radio signal on which informationis carried. The carrier can besensed to determine the presence of a signalchannel Either a single frequency or a pair ofradio frequencies used as acommunication path.
chip The length of time to transmit either azero or a one in a binary pulsecode.
chip rate Number of chips per second (e.g., forGPS C/A code = 1.023 MHz).
Number of chips per second (e.g., for GLONASSCT code = 0.511MHz).
configuration A set of conditions or parameters that define the structure of an item. Aconfiguration defines the GPS processing andcharacteristics of the RS-232 interface ports. The term configuration canalso define the hardwarecomponents that comprise a subsystem or system.
data bits The bits in a byte of data whichcarry the actual information.
datum基准Refers to a mathematical model of theearth. Many local datums modelthe earth for a small region: e.g., Tokyodatum, Alaska, NAD-27 (NorthAmerica). Others, WGS-84, for example, modelthe whole earth.
DCE Data Communications Equipment. Theequipment that provides thefunctions required to establish, maintain, andterminate acommunication connection. Any equipment thatconnects to DTE usingan RS-232 or CCITT V.24 standard interface.
default setting A preset or initial value thatis assumed to be the preferred orappropriate selection for most situations. TheNAVIOR-24SGPS/GLONASS receiver is shipped with factorydefault configurationsettings; the settings were determined by LabNAVIS.
DGNSS reference station A device that tracksall GPS/GLONASS satellites in view, periodicallyperforms inter-channel calibrations, andcalculates and transmits differential corrections.
Differential capable A term used to describe aGPS/GLONASS receiver that is capable ofreceiving and applying differential GPS/GLONASScorrections
DGNSS A procedure of correcting GPS/GLONASSsolutions to achieveimproved position accuracy. DifferentialGPS/GLONASS provides to 5meter position accuracy.
Differential accuracy is obtained by applyingcorrections determined by the stationaryDifferential GPS/GLONASSReference Station to the GPS/GLONASS datacollected by the RPUunit on-board the vehicle
Differential processing GPS/GLONASSmeasurements can be differenced between receivers,satellites, and epochs. Although manycombinations are possible, thepresent convention for differential processingof GPS/GLONASS phasemeasurements is to take differences betweenreceivers (singledifference), then between satellites (doubledifference), then betweenmeasurement epochs (triple difference).
Differential relative positioning Determination of relative coordinates of two ormore receivers whichare simultaneously tracking the samesatellites. Static differential GPS involves determining baseline vectors betweenpairs of receivers. Alsosee differential GPS/GLONASS
dilution of precision A description of thepurely geometrical contribution to the uncertaintyin a position fix, given by the expression DOP= SQRT TRACE (AA)where AA is the design matrix for the instantaneous position solution(dependent on satellite receiver geometry). TheDOP factor depends onthe parameters of the position-fix solution.Standard terms for the GPSapplication are:
GDOP: Geometric (three position coordinates plus clock offset in thesolution)
PDOP: Position (three coordinates)
HDOP: Horizontal (two horizontal coordinates)
VDOP: Vertical (height only) TDOP: Time (clock off set only)
DOP See dilution of precision.
Doppler aiding The use of Doppler carrier-phase measurements to smooth code-phaseposition measurements.
Doppler shift The apparent change in frequencyof a received signal due to the rate ofchange of the range between the transmitter andreceiver.
earth-centeredearth-fixed Cartesian coordinate system where the Xdirection is the intersection ofthe prime meridian (Greenwich) with theequator. The vectors rotate with the earth. Z is the direction of the spinaxiselevation angle The angle between the line ofsight vector and the horizontal plane.
elevation mask angle A measure of the minimumelevation angle仰角, above the horizon, abovewhich a GPS/GLONASS satellite must be locatedbefore the signalsfrom the satellite will be used to compute a GPS/GLONASS locationsolution. Satellites below the elevation angleare considered unusable.
The elevation mask angle is used to prevent theGPS/GLONASSreceiver from computing position solutionsusing satellites which arelikely to be obscured by buildings ormountains.
ellipsoid椭圆体In geodesy, unless otherwise specified, a mathematical figure formed by revolving an ellipse about its minor axis. Itis often used interchangeably with spheroid. Two quantities define an ellipsoid; theseare usually given as the length of these mimajor axis, a, and theflattening, f = (a - b)/a, where b is thelength of the semiminor axis.
ephemeris星历A set of parameters that describe thesatellite orbit very accurately. It isused by the receiver to compute the position ofthe satellite. Thisinformation is broadcast by the satellites.
epoch Measurement interval or data frequency,as in making observationsevery 15 seconds. Loading data using 30-secondepochs means loadingevery other measurement.
firmware A set of software computer/processor instructions that are permanently or semi-permanently resident in read-onlymemory
frequency The number of vibrations per secondof an audio or radio signal.Measured in hertz (Hz), kilohertz (kHz), ormegahertz (MHz).
GPS frequencies are: L1 = 1575.42 MHz
GLONASS frequencies are L1 = 1598,0625…1605,375MHz
GDOP Geometric Dilution of Precision. GDOP describes how much anuncertainty in pseudo-range and time affectsthe uncertainty in aposition solution. GDOP depends on where thesatellites are relative tothe GPS receiver and on GPS clock offsets
geodetic datum大地基准A mathematical model designed tobest fit part or all of the geoid. It isdefined by an ellipsoid and the relationship between the ellipsoid and apoint on the topographic surface established asthe origin of datum. Thisrelationship can be defined by six quantities,generally (but notnecessarily) the geodetic latitude, longitude,and the height of the origin,the two components of the deflection of thevertical at the origin, andthe geodetic azimuth of a line from the originto some other point. TheGPS uses WGS-84.
geoid The actual physical shape of the earthwhich is hard to describemathematically because of the local surface irregularities and sea-landvariations. In geodetic terms it is theparticular equipotential surfacewhich coincides with mean sea level, and whichmay be imagined toextend through the continents. This surface is everywhere perpendicularto the force of gravity.
GLONASS Russian Federation’s GLObal'naya NAvigatsionnayaSputnikovaya Sistema or GLObal NAvigationSatelliteSystem (GLONASS).
GPD GPS with differential corrections applied.
GPS Global Positioning System. A constellationof 24 radio navigation (notcommunication) satellites which transmitsignals used (by GPSreceivers) to determine precise location(position, velocity, and time)solutions. GPS signals are availableworld-wide, 24 hours a day, in allweather conditions. This system also includes 5monitor groundstations, 1 master control ground station, and3 upload ground stations.
GPS antenna An antenna designed to receive GPS radio navigation signals.
GPS processor An electronic device thatinterprets the GPS radio navigation signals (received by a GPS antenna) and determines alocation solution. The GPS processor may also be able to apply (anddetermine) differentialGPS corrections
GPS receiver The combination of a GPS antennaand a GPS processor.包含GPS天线与GPS模块。
GPS time The length of the second is fixed andis determined by primary atomicfrequency standards. Leap-seconds闰秒 are not used,as they are in UTC.Therefore, GPS time and UTC differ by avariable whole number ofseconds.
HDOP Horizontal Dilution of Precision.
HOW Handover word. The word in the GPS messagethat contains time synchronization information for the transferfrom C/A to P-code.
interface cable (serial) The interface cableallows data to flow between the NAVIOR-24S andthe communication equipment. One end of thecable has a 9-pin femaleRS-232 connector has a 9-pin male and the otherend of this cable has a 9-pin female RS-232 connectors. InterferenceRefers to the unwantedoccurrences on communication channels that area result of natural orman-made noises and signals, not properly apart of the signals beingtransmitted or received.
Integrated Doppler A measurement of Doppler shiftfrequency or phase over time
IODE Issue Of Data, Ephemeris. Part of the navigation data. It is the issuenumber of the ephemeris information. A new ephemeris is availableusually on the hour. Especially important for Differential GPS operationthat the IODE change is tracked at both thereference station and mobilestations.
jamming Interference (in either transmitting orreceiving signals) caused by other radio signals at exactly or approximately thesame frequency.
Kalman filter A numerical method used to tracka time-varying signal in the presence of noise. If the signal can be characterized bysome number ofparameters that vary slowly with time, then Kalman filtering can beused to tell how incoming raw measurements should be processed tobest estimate those parameters as a function oftime.
masks See satellite masks
maximum PDOP A measure of the maximum Position Dilution of Precision (PDOP) thatis acceptable in order for the GPS processor todetermine a locationsolution (see PDOP)
NAVSTAR The name given to the GPS satellites,built by Rockwell International,which is an acronym formed from NAVigationSystem with Time AndRanging.
NMEA National Marine Electronics Association.An association that defines marine electronic interface standards for thepurpose of serving thepublic interest
NMEA 0183 message NMEA 0183 is a standard for interfacing marine electronics navigational devices. The standard specifiesthe message format used tocommunicate with marine devices/components.
packet An “envelope” for data, which contains addresses and error checking information as well as the data itself.
parity A scheme for detecting certain errors indata transmission. Paritydefines the condition (i.e., even or odd偶数或奇数) ofthe number of items in a set
(e.g., bits in a byte).
PDOP Position Dilution of Precision. PDOP is aunitless figure of merit that
describes how an uncertainty in pseudo-range affects position solutions.
PDOP constellation switch A value, based on PDOP, that defines when theGPS receiver/processorshould switch between 2-D and 3-D GPS modes.The PDOP constellation switch is only active when theGPS mode of operation isset to Auto.
PRN Pseudo-random noise. Each GPS satellitegenerates its own distinctivePRN code, which is modulated onto each carrier.The PRN code servesas identification of the satellite, as a timingsignal, and as a subcarrierfor the navigation data.
protocol A formal set of rules that describe amethod of communication. The
protocol governs the format and control ofinputs and outputs.
pseudo-range A measure of the range from theGPS antenna to a GPS satellite.Pseudo-range is obtained by multiplying thespeed of light by theapparent transit time of the signal from theGPS satellite. Pseudo-rangediffers from actual range because the satelliteand user clocks are offset弥补from GPS time and because of propagation传播 delaysand other errors
RAM Random-Access Memoryrandom-access memory Memory in which information can be referred to in an arbitrary任意orrandom order. The contents of RAM are lost whenthe System Unit isturned off
range A term used to refer to the distanceradio signals can travel before they
must be received or repeated due to loss ofsignal strength, the curvature曲率of the earth and the noise introduced becauseof moisture in the airsurrounding the earth's surface.
range rate The rate of change of range betweenthe satellite and receiver. The range to a satellite changes due to satelliteand observer motions. Rangerate is determined by measuring the Dopplershift of the satellite beacon信标carrier.
read-only memory Memory whose contents can beread, but not changed. Information isplaced into ROM only once. The contents of ROMare not erased when the system unit's power is turned off.
real time clock An electronic clock, usually batterypowered, that keeps current time.
Used by a GPS receiver during a warm or hotstart to determine whereto search for GPS satellite signals.
Relative positioning The process of determiningthe vector distance between two points andthe coordinates of one spot relative toanother. This technique yields
GPS positions with greater precision than asingle point positioningmode can.
rise/set time Refers to the period during whicha satellite is visible; i.e., has an elevation angle that is above the elevation mask. A satellite is said to“rise” when its elevation angle exceeds themask and “set” when theelevation drops below the mask.
ROM Read-Only Memory.
RS-232 A communication standard for digitaldata. Specifies a number of signal
and control lines. RS-232 is often associatedwith a 9 pin connectorcalled a DB-9
RTCM Radio Technical Commission for MaritimeServices. Commission thatrecommends standards for differential GPSservices. “RTCMRecommended Standards For Differential GPSService,” prepared by RTCM Special Committee No. 104 (RTCM SC-104),defines acommunication protocol for sending GPS differential corrections from adifferential reference station to remote GPSreceivers.
satellite masks As satellites approach thehorizon, their signals can become weak anddistorted, preventing the receiver fromgathering accurate data. Satellite masks enable you to establish criteria forusing satellite data in aposition solution. There are three types ofsatellite masks: Elevation,SNR, and PDOP.
SA Selective Availability. This is the name ofthe policy and theimplementation scheme by which unauthorizedusers of GPS will havetheir accuracy limited to 100 meters 2D RMShorizontal and 156 meters2D RMS vertical.
SEP Spherical Error Probability.球面误差概率The radius ofa sphere such that 50% of theposition estimates will fall within the surfaceof the sphere.
Serial communication A system of sending bitsof data on a single channel one after the other,rather than simultaneously.
serial port A port in which each bit of informationis brought in/out on a single
channel. Serial ports are designed for devicesthat receive data one bit ata time.
signal to noise level GPS/GLONASS signals withSNRs that do not meet the mask criteriaare considered unusable.
signal to noise ratio A measure of the relativepower levels of a communication signal andnoise on a data line. SNR is expressed indecibels (dB).
SNR Signal to Noise Ratio.
spread spectrum The received GPS/GLONASS signalis a wide bandwidth, low-power
signal (-160dBW). This property results frommodulating the L-bandsignal with a PRN code in order to spread thesignal energy over abandwidth which is much greater than the signalinformationbandwidth. This is done to provide the abilityto receive all satellitesunambiguously and to provide some resistance tonoise and multipath.
SPS Standard Positioning Service. Refers to theGPS as available to theauthorized user.
start bit In asynchronous transmission, thestart bit is appended to the beginning
of a character so that the bit sync andcharacter sync can occur at thereceiver equipment.
stop bit In asynchronous transmission, the stopbit is appended to the end of
each character. It sets the receiving hardwareto a condition where it
looks for the start bit of a new character.
SV Space Vehicle (GPS satellite).
Synchronous communication A method of sending digital data in which thebits come at fixed, ratherthan random, times and are synchronized to aclock.
URA Satellite user range accuracy. The URA issent by the satellite and iscomputed by the GPS operators. It is astatistical indicatory of thecontribution of the apparent clock andephemeris prediction accuraciesto the ranging accuracies obtainable with aspecific satellite based onhistorical data.
UTC Universal Time Coordinated. Uniform atomictime system/standard that
is maintained by the US Naval Observatory. UTCdefines the local solarmean time at the Greenwich Meridian.
UTC offset The difference between local timeand UTC (Example: UTC - EST = 5hours).