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MN002000A © 2004 Navman NZ Ltd. All rights reserved. Proprietary information and specifications subject to change without notice.
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.