Navman 11 User Manual

Page 74

km: Kilometre.
L1 Band: the 1575.42 MHz GPS carrier frequency

which contains the C/A code, P-code, and

navigation messages used by commercial GPS

receivers.
L2 Band: a secondary GPS carrier, containing

only P-code, used primarily to calculate signal

delays caused by the ionosphere. The L2

frequency is 1227.60 MHz.
LD/LR: Line Driver/Line Receiver.
LED: Light Emitting Diode.
LPTS: Low Power Time Source.
LSB: Least Signiﬁcant Bit.
m/s: metres per second (units of velocity).
m/s/s: metres per second per second (units of

acceleration).
m/s/s/s: metres per second per second per

second (units of impulse or ‘jerk’).
Mask angle: The minimum GPS satellite elevation

angle permitted by a particular GPS receiver

design.
Measurement error variance: The square of the

standard deviation of a measurement quantity. The

standard deviation is representative of the error

typically expected in a measured value of that

quantity.
MFI: Multi-Function Interface.
MHz: Megahertz.
MR: Master Reset.
MSB: Most Signiﬁcant Bit.
MSL: Mean Sea Level.
MTBF: Mean Time Between Failure.
Multipath errors: GPS positioning errors caused

by the interaction of the GPS satellite signal and its

reﬂections.
mV: Milli-Volt.
mW: Milli-Watt.
NF: Noise Factor (or Noise Figure).
NMEA: National Marine Electronics Association.
Obscuration: term used to describe periods of

time when a GPS receiver’s line-of-sight to GPS

satellites is blocked by natural or man-made

objects.
OEM: Original Equipment Manufacturer.
Over-determined solution: the solution of a

system of equations containing more equations

than unknowns. The GPS receiver computes,

when possible, an over-determined solution using

the measurements from all GPS satellites it can

track, instead of the four necessary for a three-

dimensional position solution.
P-Code Precision Code: a spread spectrum

direct sequence code that is used primarily by

military GPS receivers to determine the range to

the transmitting GPS satellite.
Parallel receiver: a receiver that monitors four or

more satellites simultaneously.
PC: Personal Computer.
PCMCIA: Personal Computer Memory Card

International Association.
PDOP: Position Dilution of Precision. A measure

of how much the error in the position estimate

produced from satellite range measurements is

ampliﬁed by a poor arrangement of the satellites

with respect to the receiver antenna.
Pi (or �): the mathematical constant having a

value of approximately 3.14159.
P-P: Peak-to-Peak.
PPS: Pulse Per Second.
Note: PPS can also stand for Precise Positioning

Service. The GPS positioning, velocity, and time

service which will be available on a continuous,

worldwide basis to users authorised by the DoD.
PRN: Pseudo-random Noise Number. The identity

of the GPS satellites as determined by a GPS

receiver. Since all GPS satellites must transmit on

the same frequency, they are distinguished by their

pseudo-random noise codes.
PRR: Pseudo-Range Rate.
Pseudo-range: the calculated range from the

GPS receiver to the satellite determined by

measuring the phase shift of the PRN code

received from the satellite with the internally

generated PRN code from the receiver. Because

of atmospheric and timing effects, this time is

not exact. Therefore, it is called a pseudo-range

instead of a true range.
PSF: Post Select Filter.
PVT: Position, velocity, and time.
RAM: Random Access Memory.
Receiver channels: a GPS receiver speciﬁcation

which indicates the number of independent

hardware signal processing channels included in

the receiver design.
RF: Radio Frequency.
RFI: Radio Frequency Interference.
ROM: Read-Only Memory.
RTC: Real-Time Clock.

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