NavCom LAND-PAK Rev.N - Manual (Page 187)

Technical Reference Manual Rev. N
Glossary - 185
Glossary
.yym files see meteorological files (where yy = two digit year data was collected).
.yyn files see navigation files (where yy = two digit year data was collected).
.yyo files see observation files (where yy = two digit year data was collected).
almanac files an almanac file contains orbit information, clock corrections, and atmospheric
delay parameters for all satellites tracked. It is transmitted to a receiver from a satellite and is
used by mission planning software.
alt see altitude.
altitude vertical distance above the ellipsoid or geoid. It is always stored as height above
ellipsoid in the GPS receiver but can be displayed as height above ellipsoid (HAE) or height
above mean sea level (MSL).
Antenna Phase Center (APC) The point in an antenna where the GPS signal from the
satellites is received. The height above ground of the APC must be measured accurately to
ensure accurate GPS readings. The APC height can be calculated by adding the height to an
easily measured point, such as the base of the antenna mount, to the known distance between
this point and the APC.
APC see antenna phase center or phase center.
Autonomous positioning (GPS) a mode of operation in which a GPS receiver computes
position fixes in real time from satellite data alone, without reference to data supplied by a
reference station or orbital clock corrections. Autonomous positioning is typically the least
precise positioning procedure a GPS receiver can perform, yielding position fixes that are
precise to 100 meters with Selective Availability on, and 30 meters with S/A off.
azimuth the azimuth of a line is its direction as given by the angle between the meridian and the
line measured in a clockwise direction from the north branch of the meridian.
base station see reference station.
baud rate (bits per second) the number of bits sent or received each second. For example, a
baud rate of 9600 means there is a data flow of 9600 bits each second. One character roughly
equals 10 bits.
bits per second see baud rate.
bps see baud rate.
BSW (British Standard Whitworth) a type of coarse screw thread. A 5/8” diameter BSW is the
standard mount for survey instruments.
C/A code see Coarse Acquisition code.
CAN BUS a balanced (differential) 2-wire interface that uses an asynchronous transmission
scheme. Often used for communications in vehicular applications.
channel a channel of a GPS receiver consists of the circuitry necessary to receive the signal for
a single GPS satellite.
civilian code see Coarse Acquisition code.
Coarse Acquisition code (C/A or Civilian code)
the pseudo-random code generated by GPS satellites. It is intended for civilian use and the
accuracy of readings using this code can be degraded if selective availability (S/A) is introduced
by the US Department of Defense.