Introduction
Topcon HiPer Lite and HiPer Lite+ Operator’s Manual
1-6
Conclusion
Surveyors can use Topcon GPS+ receivers to collect data
from a network of satellites and control stations to
triangulate precise points anywhere on Earth.
This overview simply outlines the basics of GPS and
GLONASS positioning. For more detailed information,
visit the TPS website (www.topconps.com/gpstutorial/).
Receiver Overview
When power is turned on and the receiver self-test completes,
the receiver’s 20 channels initialize and begin tracking visible
GPS satellites. Each of the receiver’s channels can be used to
track C/A-L1, P-L1, or P-L2 signals. The number of channels
available allows the receiver to track all visible GPS satellites at
any time and location. The GPS antenna receives the different
signals for processing.
An internal GPS antenna equipped with a low noise amplifier
(LNA) and the receiver’s radio frequency (RF) device are
connected with a coaxial cable. The wide-band signal received
is down-converted, filtered, digitized, and assigned to different
channels. The receiver processor controls the process of signal
tracking.
Once the signal is locked in the channel, it is demodulated and
necessary signal parameters (carrier and code phases) are
measured. Also, broadcast navigation data are retrieved from
the navigation frame.
After the receiver locks on to four or more satellites, it is
possible to solve the so-called “absolute positioning problem”
and compute the receiver’s coordinates (in WGS-84) and time.
All this information is stored in the receiver’s memory, which
can be downloaded later onto a computer and processed using a
post-processing software package. When the receiver is run in
RTK mode, raw data measurements can also be recorded into
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