User's Manual

4 Setup Guidelines
32 SPSx50 Modular GPS Receiver User Guide
Base station operation guidelines
For all GPS Real-Time Kinematic (RTK) operations, you require both a base station and
a rover.
RTK operation provides centimeter-level accuracy by eliminating errors that are
present in the GPS system. A receiver placed at a known position (the base station)
tracks the satellites that are being tracked by the rover receiver, at the same time that
the rover is tracking them. Errors in the GPS system are monitored at the fixed (and
known) base station, and a series of position corrections are computed. The
corrections are sent through a radio link to the rover receiver, where they are used to
correct the real time positions of the rover.
This section discusses the base station component and its role in providing an RTK
solution.
Base station components
The base station has the following components:
• GPS receiver
• GPS antenna
• base station radio
• power supply
GPS receiver and GPS antenna
The base station GPS receiver can be one of following types:
• A Smart GPS antenna, such as the SPSx80 receiver, incorporates a GPS receiver,
GPS antenna, power supply, and base station radio into a single compact unit. A
Smart GPS antenna can be rapidly set up on a tripod, fixed height tripod, or
T-Bar anywhere that is convenient on the jobsite.
• A modular GPS receiver, such as the SPSx50 receiver, incorporates a GPS
receiver, power supply, and base station radio in a single unit. The GPS antenna
and, optionally, the base station radio antenna is separate from the receiver.
Because the GPS antenna is separate, you can use the following optimized
components:
– a geodetic antenna with large ground plane, to eliminate multipath (the
major source of GPS errors) at the base station
– a high gain or directional radio antenna, to increase broadcast range and to
provide maximum coverage
You can also place a modular GPS receiver in an easily accessible and secure
location, safe from theft and the weather, while the antennas are placed high on
a tower or building, clear of obstructions and able to deliver maximum
performance.
You can use either type of receiver in a permanent, semi-permanent, or daily quick
setup configuration. If semi-permanent or permanent operation is required, however,
the modular receiver delivers significant advantages.