Navman 11 User Manual

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