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G7 Installation & Operation
Glossary
1PPS
Pulse-per-second. Used in hardware timing. A pulse is generated
in conjunction with a time stamp. This defines the instant when
the time stamp is applicable.
base station
Also called heading station. A base station in construction, is a
receiver placed at a known point on a jobsite that tracks the same
satellites as an RTK rover and provides a real-time differential
correction message stream through radio to the rover, to obtain
centimeter level positions on a continuous real-time basis. A base
station can also be a part of a virtual heading station network, or a
location at which GPS observations are collected over a period of
time, for subsequent postprocessing to obtain the most accurate
position for the location.
carrier
A radio wave having at least one characteristic (such as frequency,
amplitude, or phase) that can be varied from a known heading value
by modulation.
carrier
The frequency of the unmodulated fundamental output of a radio
frequency
transmitter. The GPS L1 carrier frequency is 1575.42 MHz.
carrier phase
The time taken for the L1 or L2 carrier signal generated by the
satellite to reach the GPS receiver. Measuring the number of carrier
waves between the satellite and receiver is a very accurate method
of calculating the distance between them.
CMR
Compact Measurement Record. A real-time message format
developed by Trimble for broadcasting corrections to other Trimble
CMR+
mainboard receivers. CMR is a more efficient alternative to RTCM.
DGPS
See real-time differential GPS.
differential
Differential correction is the process of correcting GPS data
correction
collected on a rover with data collected simultaneously at a base
station. Because the base station is on a known location, any errors
in data collected at the base station can be measured, and the
necessary corrections applied to the rover data.
Differential correction can be done in real-time, or after the data has
been collected by postprocessing.
Document PN 29010107 V1r1
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