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MN002000A © 2004 Navman NZ Ltd. All rights reserved. Proprietary information and specifications subject to change without notice.
Appendix A: Acronyms,
abbreviations, and glossary
This appendix provides a list of all acronyms,
abbreviations, and selected terms used in this
document, together with their associated meaning.
2D: Two Dimensional.
2Drms: Two Dimensional root mean square.
3D: Three Dimensional.
3Drms: Three Dimensional root mean square.
AAMP: Advanced Architecture Micro-Processor.
A/D: Analog/Digital.
Almanac: a set of orbital parameters that allows
calculation of approximate GPS satellite positions
and velocities. The almanac is used by a GPS
receiver to determine satellite visibility and as an
aid during acquisition of GPS satellite signals. The
almanac is a subset of satellite ephemeris data
and is updated weekly by GPS Control.
Altitude hold: a technique that allows navigation
using measurements from three GPS satellites
plus an independent value of altitude.
Altitude hold enable command: this message
allows the application processor to enable or
disable the ‘altitude hold’ feature.
Altitude hold mode: a navigation mode during
which a value of altitude is processed by the
Kalman filter as if it were a range measurement
from a satellite at the Earth’s centre (WGS-84
reference ellipsoid centre).
AP: Application Processor. The processor
connected to the Jupiter GPS receiver port which
controls the receiver with command messages and
uses data from output messages.
ASCII: American Standard Code for Information
Interchange.
ATO: Acquisition Time-Out.
Auto hold: The receiver will use the last altitude
calculated in 3D navigation as the current value
of held altitude when entering ‘altitude hold’
2D navigation. It will continue to use this value
throughout this altitude hold event unless an
‘amended altitude’ command is received from the
application processor. The 3D calculated altitude
used in this way is called an ‘auto hold’ altitude.
B: Boolean.
Baud: (See bps.)
BIT: Built-In Test.
Block I satellite: satellites designed and built to
support GPS development and testing. A total of
10 Block I satellites were successfully launched
between February 1978 and October 1989.
Block II satellite: satellites designed and built to
support GPS ‘Space Segment’ operation. A total of
28 Block II satellites had been built and launched
as of August 1995.
Block IIR satellite: satellites designed to replace
Block II satellites.
bps: bits per second (sometimes referred to as
baud rate)
C: Celsius.
C/A
: Code Coarse/Acquisition Code. A spread
spectrum direct sequence code that is used
primarily by commercial GPS receivers to
determine the range to the transmitting GPS
satellite.
CEP: Circular Error Probable. The radius of
a circle, centred at the user’s true location,
that contains 50 % of the individual position
measurements made using a particular navigation
system.
Clock error: the uncompensated difference
between synchronous GPS system time and time
best known within the GPS receiver.
CMOS: Complimentary Metal Oxide
Semiconductor.
C/No: Carrier-to-Noise density ratio. Also,
Channel Signal-To-Noise.
COG: Course Over Ground.
Cold start: a condition in which the GPS receiver
can arrive at a navigation solution without initial
position, time, current ephemeris, and almanac
data.
Control segment: the master control station and
the globally dispersed monitor stations used to
manage the GPS satellites, determine their precise
orbital parameters, and synchronise their clocks.
dB: Decibel.
DB-9: 9-pin D-subminiature connector.
DB-25: 25-pin D-subminiature connector.
dBiC: Decibel-isotropic-Circular (measure of
power relative to an isotropic antenna with circular
polarisation).
dBm: Decibel- milliwatt (measure of power relative
to one milliwatt).
dBW: Decibel-Watt (measure of power relative to
one watt).
DC: Direct Current.
DGPS: Differential GPS. A technique to improve