GeoSteer®
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PN 2006410—ENG Rev. B
Modem
This is a data communications device that transmits and receives data.
MSL
Mean Sea Level
—This is the average level of the ocean surface which has an
elevation of zero.
Multipath
This is when the same radio signal travels to a GNSS receiver using different paths.
For example a radio signal may get to a GPS receiver directly from the satellite, but
it could also get to the receiver by first bouncing off of an object (such as a building
or tree) and then going to the receiver. The two signals are the same information
but since one bounces off an object it is slower to arrive. This creates error in the
GNSS position as the timings for the distances to the GNSS satellites are wrong.
NMEA
National Marine Electronics Association
—This is a group that provides a
standard communication protocol for marine and GPS devices.
NMEA 0183
This is a serial communication protocol standard defined by NMEA for marine
instruments. Widely adopted by all GPS/GNSS receiver manufactures.
NTRIP
Networked Transport of RTCM via Internet Protocol
—This is a protocol for
streaming Global Navigation Satellite System (GNSS) data over the Internet. This
information can be used to get a RTK correction without a local Base Station.
OmniSTAR
This is a fee-based commercial SBAS service that provides differential GPS
corrections to subscribers. OmniSTAR provides four levels of service: VBS, G2, XP,
and HP which provide different levels of accuracy for a fee.
OnTrac2
() This is a Novariant based Mechanical Drive Unit attached to the
steering wheel of a vehicle for an AutoSteer solution.
P-Code
A 6,187,100,000,000 bit sequence of pseudorandom noise GPS that satellites
transmit. This code is unique for each satellite and repeats once a week. Because
the code is much longer it is possible for GPS receives to calculate a more accurate
position. This code is encrypted and only used by the United States Military.
GeoSteer
A Novariant steering solution which utilizes dual, multi-frequency antennas.
PDOP
Position Dilution of Precision
—This is a term that describes the three
dimensional quality of a GPS position based on the satellite geometry that is used
to calculate it. The lower the number the better the quality.
PIN
Personal Identification Number
—This is a pass code used to unlock or gain
access to accounts.
Port
For network communications this is a software application or process the network
can access and communicate with.
PPP
Point-to-Point Protocol
—This is a computer networking protocol used to
communicate between two devices.
Precision
(Not the same as Accuracy) This is the measure of the closeness of multiple
measurements to each other under unchanged conditions for each
measurement. For example, how close are multiple GPS position points of the
same position to each other? For Precision, measurement points are compared
with each other but NOT with the actual measurement. This is also often called as
Repeatability.
PRL
Preferred Roaming List
—A database residing in a wireless (primarily CDMA)
device such as a cell phone, that contains information used during the system
selection and acquisition process.
PRN
Pseudo-Random Noise
—This is a repeating pattern of random radio frequency
noise. Each satellite transmits a different PRN which allows GPS receivers to identify
which satellite is sending the signal. The PRN for a satellite is the identifier or name
of the GPS, WAAS, EGNOS, or other navigation satellite. Since the PRN repeats at a
regular interval, the timing can be determined from this signal as well.
QZSS
Quasi-Zenith Satellite System
—This is a space based GPS correction source
managed by the Japanese government to area to augment the GPS and improve
positional accuracy. QZSS is only available over Japan and surrounding areas.