Field Manual 3-34.331 TOPOGRAPHIC SURVEYING 16 January 2001

TOC Chap1 2 3 4 5 6 7 8 9 10 11 AppA AppB AppC AppD Gl Bib



perspective to
a azimuth of line
a angle
k correction for the earth's curvature
' minute(s)
" second(s)
E delta easting
N delta northing
f latitude
F phi
h1 elevation of the occupied station
l longitude
q Theta
r symbol for rho - radius of curvature
s grid distance
s sigma
t tau
z mean observed zenith distance
1D one dimensional
1DRMS 1-deviation root-mean-square
1LT first lieutenant
1SG first sergeant
2D two dimensional
2DRMS 2-deviation root-mean-square
3D three dimensional
3DRMS 3-deviation root-mean-square
A/M angle measure
AAF Army airfield
AAL additional authorizations list
AC alternating current
accuracy the degree of conformity with a standard or the degree of perfection attained in a measurement; accuracy relates to the quality of a result and is distinguished from precision, which relates to the quality of the operation used to obtain the result
actual error the difference between the accepted value and the measured value of a physical quantity
ADA air-defense artillery
adj adjusted
adjust adjustment
adjusted position an adjusted value for the horizontal or vertical position of a survey station, in which discrepancies due to errors in the observed data are removed, that forms a coordinated and correlated system of stations
AE allowable error
AEC angular error of closure
aeronautical beacon a visual NAVAID displaying flashes of white and/or colored light to indicate the location of an airport, a heliport, a landmark, a certain point of a federal airway in mountainous terrain, or an obstruction
AG Adjutant General
AH ampere-hour
air-navigation facility any facility used in, available for use in, or designed for use in the aid of air navigation (this includes landing areas; lights; any apparatus or equipment used for disseminating weather information, signaling, radio-directional finding, or radio or other electrical communication; and any other structure or mechanism having a similar purpose of guiding or controlling the flight, the landing, or the takeoff of aircraft)
airport elevation the highest point of an airport's usable runways measured in feet from the MSL
airport lighting various lighting aids installed on airports. These aids can include
1) airport rotating beacons�a visual NAVAID that is operated at many airports. At civil airports, alternate white and green flashes indicate the location of the airport. At military airfields, the beacon is differentiated by dual peak (two quick) white flashes between the green flashes;

2) approach-light systems (ALSs)�an airport lighting facility which provides visual guidance to landing aircraft by radiating light beams in a directional pattern by which the pilot aligns the aircraft with the extended runway centerline on his final approach for landing. A number of ALS configurations exist, both with and without sequenced flashing lights. One system, the omnidirectional ALS (ODALS), consists of seven omnidirectional flashing lights located in the approach area of a nonprecision approach. Five of the lights are located on the extended runway centerline and the other two lights are located one on each side of the runway threshold;

3) REILs�two synchronized flashing lights, one on each side of the runway threshold, provide rapid and positive identification of the approach end of a runway;

4) visual-approach slope indicators (VASI)�an airport lighting facility providing vertical visual-approach slope guidance to aircraft during the approach for landing by radiating a directional pattern of high-intensity, red and white, focused light beams, which indicate to the pilot if he is above, below, or on the glide path. The term VASI also has a generic connotation for a tricolor-approach slope indicator consisting of a single light unit projecting a three-color, visual-approach path into the final approach area of the runway served by the system;

5) pulse-light approach-slope indicators (PLASI)�a VASI, normally consisting of a single light unit projecting a pulsating two-color, visual-approach path into the final approach area of the runway served by the system; and

6) precision approach-path indicators (PAPI)�a VASI, consisting of a single row of two or four light units, usually installed on the left side of the runway served by the system

airport reference point the position of the approximate center of mass of all usable runways. This point is not strictly the center of mass of runways, since the runway width, thickness, or material is not considered in the computation. An ARP is not monumented; therefore, it is not recoverable on the ground
airport surveillance radar approach control radar that is used to detect and display an aircraft's position in the terminal area. The ASR provides range and azimuth information but does not provide elevation data (coverage of the ASR can extend up to 60 nautical miles)
air-route surveillance radar air-route traffic control center (ARTCC) radar used primarily to detect and display an aircraft's position while en route between terminal areas (coverage of the ARSR can extend up to 200 nautical miles)
AISI automated integrated survey instrument
ALP airport location point
ALS approach-light system
altimeter an aneroid barometer that is used for the measurement of approximate elevations or approximate differences of elevation
altitude the vertical angle that is measured between the plane of the observer's true horizon and a line to the object
ambiguity resolution with carrier-phase observations, the number of carrier-phase cycles between the receiver and the satellite is generally unknown and is referred to as the ambiguity and is an integer number. Single and double differences are also affected by ambiguities, which are formed by a linear combination of carrier-phase integer ambiguities (for example, a single or double differenced ambiguity). Where the integer ambiguities are unknown, they may be estimated by processing software. In some cases, these real-valued estimates may be used to determine the correct integer values, which are then held fixed. A float solution is derived when the real-valued estimates are used, rather than the integers
ang angle
ant antenna
AO area of operation
AOC airport obstruction chart
AP airport plan
APFT Army physical fitness test
approx approximate
Apr April
apron a defined area on an airport or heliport intended to accommodate aircraft for purposes of loading and unloading passengers or cargo, refueling, parking, or maintenance (seaplanes use a ramp for access from the water to the apron)
AR Army regulation
ARP airport reference point
ARSR air-route surveillance radar
ARTCC air-route traffic control center
ARTEP Army Training and Evaluation Program
AS antispoofing
ASCII American Standard Code for Information Interchange
ASPRS American Society of Photogrammetry and Remote Sensing
ASR airport surveillance radar
astronomical latitude the angle between the plumb line and the plane of the celestial equator; also defined as the angle between the plane of the horizon and the axis of rotation of the earth. Astronomical latitude applies only to positions on the earth and is reckoned from the astronomic equator (0�), north and south through 90�. Astronomical latitude results directly from observations of celestial bodies, which are uncorrected for deflection of the vertical
astronomical longitude the angle between the plane of the celestial meridian and the plane of an initial meridian that is arbitrarily chosen. Astronomical longitude results directly from observations on celestial bodies, uncorrected for deflection of the vertical
ATC air traffic control
Aug August
az azimuth
azimuth the direction of one object from another, usually expressed as an angle in degrees relative to true north (azimuths are usually measured in the clockwise direction, thus an azimuth of 90� indicates that the second object is due east of the first)
azimuth mark the azimuth to a marked point or adjacent station that is visible from an occupied station, which is determined for use in dependent surveys
b backward
backsight in traversing, a backsight is a sight on a previously established traverse or triangulation station, which is not the closing sight on the traverse; in leveling, a backsight is a reading on a rod that is held on a point whose elevation has been previously determined and is not the closing sight of a level line
BAQ basic allowance for quarters
base network a small network of geometric figures that is used to expand from a baseline to a line of the main scheme of a triangulation network
baseline a surveyed line that is established with more than usual care, to which surveys are referred for coordination and correlation; in GPS baseline reduction, geodetic parameters are estimated at one station relative to another, with the receivers at both sites observing common satellites simultaneously
basic control horizontal and vertical control of third- or higher-order accuracy (determined in the field and permanently marked or monumented) that is required to control further surveys
BC basic control
BCM basic-control marker
bearing the direction of one object from another, usually expressed as an angle in degrees relative to a specific primary direction (bearings differ from azimuths in that bearing values do not exceed 90�)
benchmark a relatively permanent object, natural or artificial, bearing a marked point whose elevation above or below an adopted datum is known; usually designated as a BM, such a mark is sometimes further qualified as a PBM or as a temporary BM (TBM)
BEQ bachelor enlisted quarters
bde brigade
BDE backward difference in elevation
BII basic issue items
blast pad a specially prepared surface that is placed adjacent to the ends of runways to eliminate the erosive effect of the high wind forces produced by airplanes at the beginning of their takeoff rolls
BM benchmark
bn battalion
broadcast ephemeris the predicted satellite position in its orbit as a function of time computed from the ephemeris parameters contained in the navigation message broadcast on both the L1 and L2 carrier waves
bs backsight
btry battery
C2 command and control
C Celsius
C/A-code coarse-acquisition code
CAD computer-aided design
cadastral survey a survey relating to land boundaries and subdivisions, which is made to create units suitable for the transfer of or to define the limitations of a title; surveys of the public lands of the US, including retracement surveys for the identification of and resurveys for the restoration of property lines; and for corresponding surveys outside the public lands, although such surveys are usually termed land surveys
CADD computer-aided design and drafting
carrier phase the phase (as measured at the antenna phase center of a GPS receiver) of two sinusoidal radio signals (the two carriers) that are continuously emitted by each GPS satellite
C-check collimation test for leveling
CDC consecutive Doppler counts
celestial equator a great circle on the celestial sphere on which any point is equidistant from the celestial poles (the plane of the earth's equator, if extended, would coincide with that of the celestial equator)
celestial meridian a vertical circle (the plane of which is perpendicular to the celestial equator) passing through both celestial poles
celestial pole a reference point located at the point of intersection of an indefinite extension of the earth's axis of rotation and the apparent celestial sphere
celestial sphere an imaginary sphere of infinite radius, with the earth as the center, that rotates from east to west on a prolongation of the earth's axis
central meridian the longitude of the horizontal center of a coordinate system (this longitude value is often the longitude origin of the coordinate system); in the case of the transverse Mercator projection, the CM is the great circle/geodesic at which the projection surface (the cylinder) touches or is tangent to the earth
CEOI communications-electronics operation instructions
CEP circular error probable
CESI communications-electronics standing instruction
C-factor collimation error; error of the sighting of the level
chron chronometer
chronometer a portable timekeeper with compensated balance, which is capable of showing time with extreme precision and accuracy
CID continuously integrated Doppler
circle position a prescribed setting (reading) of the horizontal circle of a direction theodolite, which is used for observing the initial station of a series of stations
circuit closure in leveling, it is the amount by which the algebraic sum of the measured differences of elevation around a circuit fails to equal zero
circumpolar star a star in any given latitude that never goes below the horizon; hence, its polar distance must be less than the given latitude; in astronomy, only those stars with a polar distance of less than 10� are considered in practical problems
cl closure
C/L centerline
clearway an area beyond the takeoff runway that is under the control of airport authorities where terrain or fixed obstacles may not extend above specified limits (these areas may be required for turbine-powered operations and the size and upward slope of the clearway will differ depending on when the aircraft was certified)
cm centimeter(s)
CM central meridian
COEI components of end item
collimation the line of sight or aiming line of an instrument when coincident with the physical alignment of the instrument; thus, a collimation error is the angle between the line of collimation (line of sight) of a telescope and the collimation axis of the instrument
comm communication
comp computer
compass locator a low-power, low- or medium-frequency (L/MF) NDB that is installed at the site of the outer or middle marker (MM) of an ILS (it can be used for navigation at distances of about 15 miles or as authorized in the approach procedure)
control the coordinated and correlated dimensional data, which are used in geodesy and cartography to determine the positions and elevations of points on the earth's surface or on a cartographic representation of that surface; a collective term for a system of marks or objects on the earth or on a map or a photograph whose positions or elevations, or both, have been or will be determined
control survey a survey that provides positions (horizontal or vertical) of points to which supplementary surveys are adjusted
CONUS continental United States
coordinate system an exact definition of a system of mathematics and geodetic constants that defines how a specific geographic location is converted to a set of two or three numbers (for example, an X- and Y-value [and possibly a Z-value]); in the cartographic context, most coordinate systems are Cartesian (the axes are orthogonal [perpendicular to each other]) and the units are the same on all axes; the principle exception to this is the spherical coordinate system of latitudes and longitudes
coordinates linear and/or angular quantities, which designate the position of a point in relation to a given reference frame; there are two general divisions of coordinates used in surveying�polar and rectangular; these may be further subdivided into three classes�plane coordinates, spherical coordinates, and space coordinates
coords coordinates
Corps Conversion a software program that converts horizontal coordinates to and from geographic, state-plane, and UTM systems on the NAD 27 and the NAD 83 and converts vertical coordinates on the NGVD 29 and the NAVD 88
Corpscon Corps Conversion
corr correction
CORS continuously operating reference station
cos cosine
CPT captain
C&R curvature and refraction
CTT common training task
cycle slips cycle slips occur when there are breaks in the continuity of signal in a satellite-receiver pair. Data sampling requires the choosing of the sampling rate and the starting and finishing epochs for the observations. Data editing is required for cycle slips and for data sampling
D ratio of side/sine
DA Department of the Army
datum the combination of an ellipsoid, that specifies the size and shape of the earth, and a base point from which the latitude and longitude of all other points are referenced. Before satellites, lasers, and computers, establishing precise values for these points was impossible. More recently, many datums have been established and substantial amounts of data collected based on each. Data based on one datum will not necessarily overlay data based on another datum. A geodetic datum is a reference surface consisting of five quantities: the latitude and longitude of an initial point, the azimuth and distance of a line from this point, and the parameters of the reference ellipsoid. It forms the basis for the computation of horizontal-control surveys in which the curvature of the earth is considered. A leveling datum is a level surface to which elevations are referred (usually, but not always, the MSL)
DD Department of Defense
dE difference in easting
DE difference in elevation
declination in a system of polar or spherical coordinates, the angle at the origin between a line to a point and the equatorial plane, measured in a plane perpendicular to the equatorial plane; the arc between the equator and the point measured on a great circle, which is perpendicular to the equator; as it relates to astronomy, the angular distance to a body on the celestial sphere that is measured north or south through 90� from the celestial equator along the hour circle of the body. Comparable to latitude on the terrestrial sphere and often used as a shortened term for magnetic declination
deflection of the vertical the angular difference, at any place, between the upward direction of a plumb line (the vertical) and the perpendicular (the normal) to the reference spheroid. This difference seldom exceeds 30 seconds and is often expressed in two components�meridian and prime vertical
deg degree(s)
det detachment
dev deviation
DGPS differential global-positioning system
dH difference in the horizontal aim
diff difference
differencing nondifferencing (one-way phase) is the measured carrier phase between one satellite and one receiver. Single differencing (first difference) is the difference between one-way measurements recorded at two receivers (for example, two receivers simultaneously observing a common satellite and differencing the recorded measurements). Double differencing (second difference) is the difference between two single differences (for example, two stations observing two satellites, forming differences between the site pair and the satellite pair). Triple differencing (double difference rate/epoch differences) is the differencing of double differences between consecutive epochs
dir direction
direct leveling the determination of DEs by the means of a continuous series of short horizontal lines. Vertical distances from these lines to adjacent ground marks are determined by direct observations on graduated rods with a leveling instrument equipped with a spirit level
direct reading the reading of the horizontal or vertical circle of a theodolite or engineer transit with the telescope in the direct position. In field notes, a direct reading is indicated with a letter D preceding the observed value
direction finder a radio receiver equipped with a directional sensing antenna used to take bearings on a radio transmitter
direction instrument theodolite a theodolite in which the graduated horizontal circle remains freed during a series of observations. The telescope is pointed on a number of signals or objects in succession and the direction of each is read on the circle (usually by means of micrometer microscopes). Direction instrument theodolites are used almost exclusively in first- and second-order triangulation
dist distance
distance angle an angle in a triangle that is opposite the side which is used as a base in the solution of the triangle or a side whose length is to be computed
distance measuring equipment equipment that is (airborne or ground) used to measure (in nautical miles) the slant-range distance of an aircraft from the DME NAVAID
DIVARTY division artillery
DMA Defense Mapping Agency
DME distance measuring equipment
DMS Defense Mapping School
dN difference in northing
DOD Department of Defense
DOP dilution of precision
DPW Directorate of Public Works
D/R direct/reverse
DRU data recording unit
dsplcd displaced
DT displaced threshold
dV difference in the vertical aim
E east
EAC echelons above corps
EC error of closure
ECEF earth centered earth fixed
ecliptic the great circle of the celestial sphere that is the apparent path of the sun among the stars or of the earth as seen from the sun. It is inclined to the celestial equator at an angle of about 23�27'
EDM electronic distance measurement
EDME electronic distance measuring equipment
Ee error in easting
elev elevation
elevation the vertical distance from a datum, usually the MSL, to a point or object on the earth's surface (not to be confused with altitude, which refers to points or objects above the earth's surface)
ell ellipsoidal
ellipsoid the mathematical shape that best describes the shape of the earth and yet is relatively simple to deal with mathematically. Ellipsoids are defined with two numbers. First, the equatorial radius is specified (also referred to as the semimajor axis). Second, one of the following three numbers is given, the polar radius (also known as the semiminor axis), the eccentricity, or the flattening. Given the equatorial radius and any one of the three secondary values, the remaining secondary values can be computed. A specific determination of the size of the earth is often referred to as an ellipsoid. For example, the phrase "Clarke ellipsoid of 1866" is frequently used to refer to the measurements of the size of the earth made by Clarke in 1866
ellipsoid height the height of an object above the reference ellipsoid in use. This term is generally used to qualify an elevation as being measured from the ellipsoid as opposed to the geoid. GPS systems calculate ellipsoidal height. The geoid height at that location must be subtracted to obtain what is commonly referred to as the elevation
elongation the point in the apparent movement of a circumpolar star when the star reaches the extreme position east or west of the meridian
EM engineer manual
en engineer
En error in northing
eng engineer
engr engineer
EOR end of runway
ephemeris time a uniform measure of time that is defined by the laws of dynamics and determined in principle from the orbital motions of the planets, specifically in the orbital motion of the earth
equation of time the algebraic difference in hour angle between apparent solar time and mean solar time (usually labeled plus or minus), as it is to be applied to mean solar time to obtain apparent solar time
equinox one of the two points of intersection of the ecliptic and the celestial equator, which is occupied by the sun when its declination is 0�
error the difference between an observed and true value; a class of small inaccuracies due to imperfections in equipment or techniques, surrounding conditions, or human limitations; not to be confused with blunders or mistakes
error of closure the amount by which a quantity obtained by a series of related measurements differs from the true or fixed value of the same quantity. These include errors of closure for the following:

Angle. The amount by which the actual sum of a series of angles fails to equal the theoretically exact value of that sum.

Azimuth. The amount by which two values of the azimuth of a line, derived by different surveys or along different routes, fail to be exactly equal to each other.

Horizon. The amount by which the sum of a series of adjacent measured horizontal angles around a point fails to equal exactly 360�. Measurement of the last angle of the series is called closing the horizon (sometimes called closure of horizon).

Leveling. The amount by which two values of the elevation of the same BM, derived by different surveys or through different survey routes or by independent observations, fail to be exactly equal to each other.

Loop. The error in the closure of a survey on itself.

Triangle. The amount by which the sum of the three observed angles of a triangle fails to equal exactly 180� plus the spherical excess of the triangle.

Traverse. The amount by which a value of the position of a traverse station, as obtained by computation through a traverse, fails to agree with another value of the same station as determined by a different set of observations or routes of survey

esc escape
f forward
F Fahrenheit
FA field artillery
FAA Federal Aviation Administration
FAA 405 Federal Aviation Administration Publication 405
FAO finance and accounting office
FAR Federal Aviation Regulation
FAR-77 Federal Aviation Regulation, Part 77
FDE forward difference in elevation
Feb February
FEBA forward edge of the battle area
FED Facilities Engineering Division
FGCC Federal Geodetic Control Committee
FGCS Federal Geodetic Control Subcommittee
final-approach course a straight-line extension of a localizer, a final approach radial/bearing, or a runway centerline, all without regard to distance
fixed elevation an elevation that has been adopted (either as a result of tide observations or previous adjustment of spirit leveling) and is held at its accepted value in any subsequent adjustment
FM field manual
FM frequency modulated
FO forward observer
foresight an observation of the distance and direction to the next instrument station. In traversing, a foresite is a point set ahead to be used for reference when resetting the transit or line or when verifying the alignment. In leveling, a foresite is the reading on a rod that is held at a point whose elevation is to be determined
FOUO for official use only
FRAGO fragmentary order
frequency the number of complete cycles per second existing in any form of wave motion
FRNP Federal Radio Navigation Plan
fs foresight
FS fire support
FSCOORD fire-support coordinator
ft feet, foot
G2 Assistant Chief of Staff, G2 (Intelligence)
G3 Assistant Chief of Staff, G3 (Operations and Plans)
GCA ground-controlled approach
GDOP geometric dilution of precision
geod geodetic
geodesy a branch of applied mathematics concerned with the determination of the size and shape of the earth (geoid). Direct measurements (triangulation, leveling, and gravimetric observations) determine the exact location of points on the earth's surface and its external gravitational field
geodetic control a system of horizontal and/or vertical control stations that have been established and adjusted by geodetic methods and in which the shape and size of the earth (geoid) have been considered in position computations
geodetic latitude the angle at which the normal (at a point on the reference spheroid) forms with the plane of the geodetic equator. Geodetic latitudes are reckoned from the equator, but in the horizontal-control survey of the US, they are computed from the latitude of station Meades Ranch as prescribed in NAD 27
geodetic leveling spirit leveling of a high order of accuracy, usually extended over large areas, to furnish accurate vertical control as a basis for the control in the vertical dimension for all surveying and mapping operations
geodetic longitude the angle between the plane of the geodetic meridian and the plane of an initial meridian. A geodetic longitude can be measured by the angle at the pole of rotation of the reference spheroid between the local and initial meridians or by the arc of the geodetic equator intercepted by those meridians. In the US, geodetic longitudes are numbered from the meridian of Greenwich, but are computed from the meridian of station Meades Ranch as prescribed in NAD 27. A geodetic longitude differs from the corresponding astronomical longitude by the amount of the prime vertical component of the local deflection of the vertical divided by the cosine of the latitude
geodetic reference system the technical name for a datum. The combination of an ellipsoid, which specifies the size and shape of the earth, and a base point from which the latitude and longitude of all other points are referenced
geodetic survey a survey of a large land area in which corrections are made for the curvature of the earth's surface
geographic coordinates an inclusive term that is generally used to designate both geodetic and astronomical coordinates
geoid the surface within or around the earth that is everywhere normal to the direction of gravity and coincides with MSL in the oceans
GEOID93 Geoid reference model 1993
GEOID96 Geoid reference model 1996
GEOID99 Geoid reference model 1999
geoid height the height of the geoid above the ellipsoid in use (this usually refers to the height of the geoid above the WGS-84 ellipsoid upon which GPS is based)
GEOREF geographic reference
GIS geographic information system
global positioning system a system (developed by the US military) based on satellites and sophisticated receivers that are capable of accurately measuring the geodetic location of a receiver at any place in the world and is widely used in surveying and navigational situations
GPS global positioning system
GPS-S global positioning system-survey
gravimeter a weighing device or instrument of sufficient sensitivity that is used to register variations in the weight of a constant mass when the mass is moved from place to place on the earth and thereby is subjected to the influence of gravity at those places
gravitation the acceleration produced by the mutual attraction of two masses, directed along the line joining their centers of mass, and of magnitude inversely proportional to the square of the distance between the two centers of mass
gravity viewed from a frame of reference freed in the earth (acceleration imparted by the earth to a mass), which is rotating the earth. Since the earth is rotating, the acceleration observed as gravity is the resultant of the acceleration of gravitation and the centrifugal acceleration arising from this rotation and the use of an earthbound rotating frame of reference.
ground-controlled approach a radar approach system operated from the ground by ATC personnel transmitting instructions to the pilot by radio (the approach may be conducted with ASR and/or PAR)
GRS geodetic reference system
GRS 80 Geodetic Reference System of 1980
GS general support
GSI glide-slope indicator
GSR ground-surveillance radar
GySgt gunnery sergeant
h ellipsoidal height
h hour(s)
H orthometric height
HARN high-accuracy reference network
H Dist horizontal distance
HDOP horizontal dilution of precision
height of instrument in spirit leveling, it is the height of the line of sight of a leveling instrument above the adopted datum. In stadia surveying, it is the height of the center of the telescope (horizontal axis) of the transit or telescopic alidade above the ground or station mark. In trigonometric leveling, it is the height of the center of the theodolite (horizontal axis) above the ground or station mark
Hg the symbol for the element mercury
HHB headquarters and headquarters battery
HHC headquarters and headquarters company
HI height of instrument
horizontal control a control point that determines horizontal positions only, with respect to parallels and meridians or to other lines of reference
horizontal refraction a natural error in surveying, which is the result of the horizontal bending of light rays between a target and an observing instrument. This error is usually caused by the differences in density of the air along the path of the light rays, resulting from temperature variations
HQ headquarters
ht height
HT height of the observed target
IEW intelligence and electronic warfare
IFR instrument flight rules
IID intermittently integrated Doppler
ILS instrument landing system
IM inner marker
imaginary surface any surface that is defined in FAR-77, subpart C. A specified surface is an imaginary surface (other than a supplemental surface) that is designated by appropriate FAA authorities for defining obstructions. This surface may or may not be the surface specified in FAR-77 for existing approach minimums. A supplemental surface is an imaginary surface designated by appropriate FAA authorities. A supplemental surface will normally lie below a specified surface and is intended to provide additional obstruction information. An object that penetrates a supplemental surface only is a supplemental obstruction
in inch(es)
INS inertial navigation system
inst instrument
instr instrument
instrument landing system a precision instrument approach system that normally consists of electronic components and visual aids (for example, localizer, glide slope, outer marker (OM), MM, and approach lights)
instrument runway a runway equipped with electronic and visual NAVAIDs
int initials
intersection method a method of determining the horizontal position of a point by observations from two or more points of known position, thus measuring directions that intersect at the station being located. A station whose horizontal position is located by intersection is known as an intersection station
ionospheric correction the ionosphere causes a delay in the propagation of a GPS signal that can be estimated with 50 percent accuracy using any recognized atmospheric model. On baselines shorter than 20 kilometers, it is mostly eliminated by relative positioning. For greater accuracy, it can be mostly eliminated by dual frequency observations and processing
isogonic chart a chart that features a system of isogonic lines, each for a different value of the magnetic declination
isogonic line a line drawn on a map or chart joining points of equal magnetic variation
ISVT initial site-visitation trip
JAG Judge Advocate General
Jan January
K a scale factor used to convert a measured distance to a grid distance
K� a scale factor used to reduce a grid distance
KE correction to easting
km kilometer(s)
KN correction to northing
landing direction indicator a device that visually indicates the direction in which landings and takeoffs should be made
lat latitude
latitude the north/south component of the spherical coordinate system most widely used to record geodetic locations. Originally, when the earth was thought to be spherical, a degree of latitude represented one degree of arc on the surface of the earth, which is referenced to the center of the earth. Now that it is known that the earth is ellipsoidal in shape, there are several types of latitude. The usual definition of latitude is the angle a line, perpendicular to the surface of the ellipsoid, forms with the plane of the equator. This is also referred to as the geographic latitude or geodetic latitude. Whenever the unqualified term latitude is used, it is generally accepted that it refers to the geographic latitude. Normal conventions dictate that north latitudes be given in degrees where positive numbers indicate north latitudes and negative numbers indicate south latitudes
L-band frequency used by SVs to exchange information
LEC linear error of closure
level datum a level surface to which elevations are referred. The generally adopted level datum for leveling in the US is the MSL. For local surveys, an arbitrary level datum is often adopted and defined in terms of an assumed elevation for some physical BM
level net Lines of spirit leveling connected together to form a system of loops or circuits extending over an area
line of sight the straight line between two points (this line is in the direction of a great circle but does not follow the curvature of the earth); also, the line extending from an instrument along which distant objects are seen when viewed with a telescope or another sighting device
L/MF low or medium frequency
localizer the component of an ILS that provides course guidance to the runway
localizer back course the course line defined by the localizer signal along the extended runway centerline in the opposite direction to the normal localizer approach course (front course)
localizer-type directional aid a NAVAID used for nonprecision instrument approaches with utility and accuracy comparable to a localizer; however, it is not part of a complete ILS and is not aligned with the runway
lon longitude
long longitude
longitude the east/west component of the spherical coordinate system most widely used to record geodetic locations. Lines of longitude are great circles/geodesics, which pass through the north and south pole, and intersect the equator. All lines of longitude proceed in a true north/south direction. The imaginary lines of longitude are assigned values that represent, in degrees of arc, the distance of the line from the prime meridian (the line of longitude that passes through Greenwich, England, is the most common prime meridian in use today)
long-range navigation an electronic navigation system by which hyperbolic LOPs are determined by measuring the difference in the time of reception of synchronized pulse signals from two fixed transmitters. The long-range navigation (LORAN) A operates in the 1750- to 1950- kilohertz frequency band. The LORAN C and D operate in the 100- to 110-kilohertz frequency band
LOP line of position
LORAN long-range navigation
LRA local reproduction authorized
LTC lieutenant colonel
m meter(s)
m minute(s)
MACOM major Army command
mag magnetic
main-scheme station a station through which the basic survey computations are carried, also called a principal station
Mar March
marker beacon an electronic NAVAID transmitting a 75-megahertz vertical-fan or bone-shaped radiation pattern. Marker beacons are identified by their modulation frequency and keying code and, when received by compatible airborne equipment, indicate to the pilot (both aurally and visually) that he is passing over the facility. Marker beacons include the following:
Basic-control marker (BCM). When installed, this normally indicates the localizer basic-control final-approach fix where approach descent is commenced.
Inner marker (IM). A marker beacon (used with an ILS category-II precision approach) that is located between the MM and the end of the ILS runway. It also marks progress during an ILS category-III approach. The IM is usually located at the point of decision height for ILS category-II approaches.
MM. A marker beacon that defines a point along the glide slope of an ILS, usually located at or near the point of decision height for ILS category-I approaches.
OM. A marker beacon that is at or near the glide-slope intercept altitude of an ILS approach. The OM is normally located 4 to 7 miles from the runway threshold on the extended centerline of the runway
mean sea level the mean surface-water level that was determined by averaging heights at all stages of the tide over a 19-year period (often used as a reference for general leveling operations)
meas measurement
meridian in a cartographic/geodetic context, a meridian is a line of longitude
met meteorological
MET missile escort team
MFR memorandum for record
MGRS military grid-reference system
mi mile(s)
micro micrometer
MID E middle easting
MID N middle northing
mil a unit of angular measurement that is equal to 1/6400 of 360� and used especially in FA
min minute(s)
minimum weather condition requirements that are established for a particular operation or type of operation (for example, instrument flight rules (IFR) takeoff or landing, alternate airport for IFR flight plans, or visual flight rules (VFR) flight)
missed approach a maneuver that is conducted by a pilot when an instrument approach cannot be completed to landing
MLRS multiple-launch rocket system
MLS microwave landing system
mm millimeter(s)
MM middle marker
mn mean
mo month
MOA memorandum of agreement
Mon Monday
monument any object or collection of objects that indicate the position on the ground of a survey station. In military surveys, the term monument usually refers to a stone or concrete station marker containing a special bronze plate on which the exact station point is marked
MOS military occupational specialty
movement area the runways (exclusive of apron areas), taxiways, and other areas of an airport/heliport, which are used for taxiing, takeoff, and landing of aircraft. At airports/heliports with a tower, specific approval for entry onto the movement area must be obtained from ATC
MRSE mean radial spherical error
MSL mean sea level
MTP mission training plan
multipath errors errors caused when one or more reflected signals, interfering with the main signal because of their common time origin but different path lengths, are superimposed with their relative phase offsets on the primary signal at the receiver. Cyclic perturbations of the carrier are caused by this superimposition as the various signals undergo changes in their relative phase offsets as the geometric relation between the nearby and distant reflecting surfaces and the satellite and receiver changes
multistation reduction geodetic parameters that are estimated at more than two stations using simultaneous observations
n geoid height
N north
NA not applicable
NAD North American Datum
NAD 27 North American Datum of 1927
NAD 83 North American Datum of 1983
nadir the point of the celestial sphere that is directly opposite the zenith and vertically downward from the observer
NAS National Airspace System
National Flight Data Center a facility in Washington, District of Columbia, that was established by the FAA to operate a central aeronautical information service for the collection, validation, and dissemination of aeronautical data in support of the activities of the government, industry, and the aviation community. The information is published in the National Flight Data Digest (NFDD)
National Flight Data Digest a daily (except weekends and Federal holidays) publication of flight information (appropriate to aeronautical charts or aeronautical publications) that provides operational flight data which is essential to safe and efficient aircraft operations
NATO North Atlantic Treaty Organization
NAVAID navigational aid
NAVAID survey the process of determining the position and/or elevation of one or more NAVAIDs and adjunctive points on associated runways or extended runway centerlines. A NAVAID survey that is performed as part of the OC survey is called a combined NAVAID survey. A NAVAID survey that is not performed as part of a normal OC survey is called a special NAVAID survey
NAVD 88 North American Vertical Datum of 1988
navigable airspace airspace at and above the minimum flight altitude that is prescribed in FARs, including airspace needed for safe takeoff and landing
navigational aid any visual or electronic device, airborne or on the surface, which provides point-to-point guidance information or position data to aircraft in flight
NAVSTAR Navigation Satellite Timing and Ranging
NBC nuclear, biological, and chemical
NCAD New Cumberland Army Depot
NCO noncommissioned officer
NCOIC noncommissioned officer in charge
NDB nondirectional beacon
NE northeast
NFDD National Flight Data Digest
NGRS National Geodetic Reference System
NGS National Geodetic Survey
NGVD 29 National Geodetic Vertical Datum of 1929
NIMA National Imagery and Mapping Agency
NL notes and legends
No. number
NOAA National Oceanic and Atmospheric Administration
nondirectional beacon an L/MF or UHF radio beacon transmitting nondirectional signals whereby the pilot of an aircraft that is equipped with direction-finding equipment can determine his bearing to or from the station. When the NDB is installed in conjunction with an ILS marker, it is normally called a compass locator
nonprecision approach procedure a standard instrument-approach procedure in which no electronic glide slope is provided (for example, VOR, TACAN, NDB, localizer, ASR, and simplified directional facility [SDF] approaches)
North American Datum the initial point of this datum is located at Meades Ranch, Kansas. Based on the Clarke spheroid of 1866, the geodetic positions of this system are derived from a readjustment of the triangulation of the entire country in which Laplace azimuths were introduced
Nov November
NSATS number of satellites
NSRS National Spatial Reference System
NW northwest
obs observed
observer's meridian a celestial meridian passing through the zenith (at the point of observation) and the celestial poles
obstruction any object that penetrates a specified surface. An object that penetrates a supplemental surface is a supplemental obstruction. The most obstructing object in a set of objects is the one that penetrates an imaginary surface further than any other object in the set
OC obstruction chart
occ occupied
OCONUS outside continental United States
Oct October
ODALS Omnidirectional Approach Light System
offset line a supplementary line that is close to and roughly parallel with a main line (measured offsets). When a line for which data are desired is in such a position that it is difficult to measure over it, the required data are obtained by running an offset line in a convenient location and measuring offsets from it to salient points on the other line
OIS obstruction identification surface
OM outer marker
op operator
open traverse a survey traverse which begins from a station of known or adopted position but does not end upon such a station
OPORD operation order
order of accuracy a mathematical ration that defines the general accuracy of measurements made in a survey (for example, first, second, third, fourth, or lower order)
ortho orthometric
orthometric height another name for the elevation of an object (the height of an object above the geoid)
OTF on the fly
OVM organization vehicle maintenance
p page(s)
PAC Personnel and Administration Center
PACS primary airport control station
PADS Position and Azimuth Determination System
PAPI precision approach-path indicator
PAR precision approach radar
parallax the apparent displacement or the difference in apparent direction of an object as seen from two different points not on a straight line with the object; also, the angular difference in direction of a celestial body as measured from two points on the earth's orbit
PBM permanent benchmark
PC personal computer
P-code precision code
PDOP positional dilution of precision
permanent benchmark a BM of as nearly permanent character as it is practicable to establish. Usually designated simply as BM. A PBM is intended to maintain its elevation with reference to an adopted datum, without change, over a long period
PFC private first class
pgdn page down
pgs pages
pgup page up
picture point a terrain feature that is easily identified on an aerial photograph and whose horizontal or vertical position or both have been determined by survey measurements. Picture points are marked on the aerial photographs by the surveyor and are used by the photomapper
PIR precise instrument runway
PLASI pulse-light approach-slope indicator
PLGR precise lightweight GPS receiver
plumb line the line of force in a geopotential field; the continuous curve to which the direction of gravity is everywhere tangential; or, the line indicated by a plumb-bob cord
PM post meridian
PMCS preventive-maintenance checks and services
POC point of contact
POL petroleum, oils, and lubricants
pos position
POV privately owned vehicle
ppm part(s) per million
PPS Precise Positioning Service
PRC pseudorange correction
precise ephemeris the precise ephemeris is the postprocessed position of a satellite in its orbit as a function of time. It is computed from data that are observed at tracking stations at fixed locations and is available from various global agencies
precision approach procedure a standard instrument-approach procedure in which an electronic glide slope is provided or used (for example, ILS and PAR approaches)
precision approach radar radar equipment usually located at military or joint-use airfields that detects and displays azimuth, elevation, and range of aircraft on the final approach course to a runway. The controller issues guidance to the pilot based on the aircraft's position and elevation relative to the touchdown point on the runway displayed on the radarscope
prime meridian the specific meridian (for example, line of longitude) that is assigned the value of zero and to which all other meridians are referenced. While Greenwich, England, is almost universally accepted as the prime meridian, several other meridians (such as the meridian of Paris) remain in use

prime vertical

the vertical circle through the east and west points of the horizon. It may be true, magnetic, compass, or grid depending upon which east or west points are involved
PRN pseudorandom noise
pseudorange measurement a measurement obtained by comparing the time signal generated by the satellite clock to the time signal generated by the receiver clock to determine propagation time and, subsequently, the range
PVC polyvinyl chloride
PX post exchange
r degrees of freedom
R1 reject value, use first mean value
R2 reject value, use second mean value
radar a device for radio detection and ranging. Radar measures the time interval between transmitted and received radio pulses and provides information on the range, azimuth, and/or elevation of objects in the path of the transmitted pulse. A primary radar system uses reflected radio signals. A secondary radar system is a system wherein a radio signal that is transmitted from a radar station initiates the transmission of a radio signal from another station
radar approach an instrument-approach procedure that uses PAR or ASR
RC ratio of closure
RDOP relative dilution of precision
REIL runway end identifier light
rep repetition
right ascension the angular distance that is measured eastward on the equator from the vernal equinox to the hour circle through the celestial body, from 0 to 24 hours
RM reference mark
RMS root-mean-square
Ro rejected by observation
RPP runway plans and profiles
RT relocated threshold
RTCM Radio Technical Commission for Maritime
RTK real-time kinematic
RTO radio/telephone operator
runway a defined rectangular area on a land airport that is prepared for the landing and takeoff run of aircraft along its length
RVR runway visual range
RVV runway visibility value
rwy runway
s seconds
S south
S1 Adjutant (United States Army)
S3 Operations and Training Officer (United States Army)
S4 Supply Officer (United States Army)
S/A selective availability
SACS secondary airport control station
sampling interval (data rate) the interval (in seconds) at which observations are logged to memory
SATO Scheduled Airline Ticket Office
SC special committee
SCP survey control point
SDF simplified directional facility
SDNCO staff duty noncommissioned officer
SE southeast
secs seconds
Sep September
SEP spherical error probable
sexagesimal system a system of notation by increments of 60 (the division of a circle into 360�, each degree into 60 minutes, and each minute into 60 seconds)
SFC sergeant first class
SGT sergeant
SIC survey information center
SIF stadia-interval factor
simplified directional facility a NAVAID that is used for nonprecision instrument approaches. The final approach course is similar to that of an ILS localizer, except that the SDF course may not be aligned with the runway and the course may be wider, resulting in less precision
sin sine
SINCGARS Single-Channel Ground-to-Air Radio System
SLC sea-level coefficient
SM soldier's manual
software GPS software is classified as data logging, postprocessing reduction, and real-time processing. Data-logging software relates to the operation of the receiver and is not field-tested. Postprocessing software should be tested using a BM data set
SOI signal operation instructions
solar day the interval of time from the transit of either the sun or the mean sun across a given meridian to the next successive transit of the same body across the same meridian; also, the duration of one rotation of the sun
solar time time based upon the rotation of the earth relative to the sun; time on the sun
SOP standing operating procedure
SPC specialist
SPCE survey planning and coordination element
SPCO survey planning and coordinating officer
spheroid any figure differing slightly from a sphere
SPHS specially prepared hard surface
spirit leveling spirit leveling follows the geoid and its associated level surfaces, which are irregular rather than any mathematically determined spheroid or ellipsoid and associated regular level surfaces
SPS Standard Positioning Service
SSF standard solution file
SSG staff sergeant
SSGCN Standards and Specifications for Geodetic Control Networks
SSI standing signal instructions
ST special text
sta station
state-plane coordinate system the meridian used as the axis of Y for computing projection tables for a state coordinate system (the CM of the system usually passes close to the center of the figure of the area or zone for which the tables are computed)
std standard
stopway an area beyond the takeoff runway that is at least as wide as the runway, is centered upon the extended runway centerline, is able to support an airplane during an aborted takeoff without causing structural damage to the airplane, and is designated by airport authorities for use in decelerating the airplane during an aborted takeoff. The location of threshold lights has no bearing on an area being designated as a stop way
STP soldier training publication
sub subtract
SV satellite vehicle
t grid azimuth
T geodetic azimuths
TA target acquisition
TAB target-acquisition battery
TACAN tactical air navigation
tactical air navigation a UHF electronic rho-theta air NAVAID, which provides suitably equipped aircraft with a continuous indication of bearing and distance to the TACAN station
tan tangent
target any object or point toward which something is directed; also, an object which reflects a sufficient amount of a radiated signal to produce an echo signal on detection equipment
TBM temporary benchmark
TCMD transportation-control and movement document
TDY temporary duty
TDZE touchdown zone elevation
TEC Topographic Engineering Center
TECHOPORD technical operation order
tel telescope
temp temperature
TG trainer's guide
thr threshold
threshold the beginning of that portion of the runway usable for landing. A DT is located at a point on the runway other than the designated beginning of the runway. The displaced area is available for takeoff or rollout of aircraft. The DT paint bar is entirely on the usable landing surface. A relocated threshold (RT) is located at a point on the runway other than the beginning of the full strength pavement. The area between the former threshold and the RT is not available for the landing or takeoff of aircraft. The abandoned runway area may or may not be available for taxiing
tidal benchmark a BM set to reference a tide staff at a tidal station and the elevation that is determined with relation to the local tidal datum
tidal datum specific tide levels, which are used as surfaces of reference for depth measurements in the sea and as a base for the determination of elevation on land. Many different datums have been used, particularly for leveling operations
TM technical manual
TMP transportation motor pool
TOD tabulated operational data
TOE table(s) of organization and equipment
topo topographic
touchdown zone the first 3,000 feet of the runway beginning at the threshold
touchdown zone elevation the highest elevation in the touchdown zone. The OC program specifications require that the TDZE will be determined only for runways with SPHSs equal to, or greater than, 3,000 feet in length
TP temporary point
TRADOC United States Army Training and Doctrine Command
transit the apparent passage of a star or another celestial body across a defined line of the celestial sphere, as a meridian, prime vertical, or almucantar; the apparent passage of a star or another celestial body across a line in the reticle of a telescope, or some line of sight; a theodolite with the telescope mounted so that it can be transited
transmissometer an apparatus used to determine visibility by measuring the transmission of light through the atmosphere and is the measurement source for determining runway visual range (RVR) and runway visibility value (RVV)
trig list an extremely or excessively precise list
tropospheric correction the troposphere causes a propagation delay of a GPS signal. This delay can be estimated using any recognized atmospheric model and can be mostly eliminated by relative positioning for short lengths and modeled for longer baselines
UDS user-defined sequence
UERE user equivalent range error
UHF ultrahigh frequency
universal transverse Mercator a series of 120 coordinate systems that are based on the transverse Mercator projection that was originally developed by the US Army for a worldwide mapping project. Sixty zones are used to map the northern hemisphere, and the remaining zones apply to the southern hemisphere. Each zone is 6� wide and is numbered. Zone 1 covers longitudes of 180� W through 174� W. The remaining zones are numbered sequentially as they move east. All zones have their origin at the equator, use the meter as the system unit, and have a false easting of 500,000 meters and a false northing of 0. A scale reduction factor of 0.9996 is used on all zones. Zones for the southern hemisphere are identical to their northern counterpart except that the false northing is set to 10,000,000 to eliminate negative Y coordinates
UPS universal polar stereographic
US United States
USA United States of America
USAADCENFB United States Army Air Defense Center and Fort Bliss
USAASA United States Army Aeronautical Services Agency
USACE United States Army Corps of Engineers
USAES United States Army Engineer School
USAF United States Air Force
USAPA United States Army Publishing Agency
USAPPC United States Army Publications and Printing Command
USCG United States Coast Guard
USC&GS United States Coast and Geodetic Survey
USGS United States Geological Survey
UTC universal time, coordinated
UTM universal transverse Mercator
VASI visual-approach slope indicator
VDOP vertical dilution of precision
vern vernier
vernal equinox that point of intersection of the ecliptic and the celestial equator, which is occupied by the sun as it changes from south to north declination on or about March 21 (same as the first of Aries, the first point of Aries, or the March equinox)
vert vertical
vertical circle a great circle of the celestial sphere (through the zenith and nadir) that is perpendicular to the horizon; also, a graduated disk (mounted on an instrument in such a manner that the plane of its graduated surface can be placed in a vertical plane), which is used primarily for measuring vertical angles in astronomical and geodetic work
vertical control the measurements taken by surveying methods for the determination of elevation only with respect to an imaginary level surface, usually the MSL
vertical-control datum any level surface (for example, the MSL) taken as a surface of reference from which to reckon elevations. Although a level surface is not a plane, the vertical-control datum is frequently referred to as the datum plane
very-high-frequency omnidirectional range a VHF NAVAID, which provides suitably equipped aircraft with a continuous indication of bearing to the VOR station
very-high-frequency omnidirectional range and tactical air navigation a navigational facility consisting of two components, a VOR and a TACAN, which provide VOR azimuth, TACAN azimuth, and TACAN distance
VFR visual flight rules
VHF very high frequency
VOR very-high-frequency omnidirectional range
VORTAC very-high-frequency omnidirectional range and tactical air navigation
W west
WAAS wide-area augmentation system
WDI wind-direction instrument
WGS World Geodetic System
WGS 72 World Geodetic System 1972
WGS 84 World Geodetic System 1984
widelaning a linear combination of the measured phases of L1 and L2, based on the frequency difference. Widelane ambiguities can be resolved easier than L1 and L2 ambiguities, because the resulting 0.862-meter wavelength is much longer than the individual L1 and L2 wavelengths. Knowledge of the widelane ambiguity helps to solve the L1 ambiguity, after which a simple computation will give the L2 ambiguity
World Geodetic System 1984 a global datum that is based on electronic technology, which is still to some degree classified. Data on the relationship of as many as 65 different datums to WGS-84 is available to the public. As a result, WGS 84 is becoming the base datum for the processing and conversion of data from one datum to any other datum. GPS is based on this datum. The difference between WGS 84 and NAD 83 is small and is generally considered to be insignificant
XVIII the Table 18 value extracted from DMS ST 045
X, Y, and Z variables used to depict coordinates in the X, Y, and Z axis
Y-code the military's classified, encrypted precision code
yr year(s)
ZD zenith distance
zen zenith
zenith the point where an infinite extension of a plumb (vertical) line, at the observer's position, pierces the celestial sphere above the observer's head
zenith distance the complement of the altitude; the angular distance from the zenith of the celestial body measured along a vertical circle