User's Manual

4 Setup Guidelines
34 SPSx80 and SPSx81 Smart GPS Antennas User Guide
Choose a rover receiver according to the needs of the job:
• A Smart GPS antenna, such as the SPSx80 or SPSx81, incorporates the GPS
receiver, GPS antenna, power supply, and receive radio into a single compact
unit. A Smart GPS antenna can be rapidly set up on a pole, vehicle, or backpack.
This makes it easy to carry when you are measuring around the jobsite.
• A Modular GPS receiver, such as the SPSx50 or SPSx81, incorporates the GPS
receiver, receive radio, and power supply into a single unit. The GPS antenna
and, optionally, the receive radio antenna, is separate from the receiver. When
you use a modular GPS receiver as a rover, you can use optimized components
placed in the best locations for your application. For example:
– A small, lightweight rover antenna can be mounted on a pole or backpack;
placed in a high, inaccessible location on a marine vessel mast or cabin; or
placed on a site vehicle roof or truck bed.
– A rubber duck radio antenna, or an external radio antenna, can be
mounted on a vehicle or vessel roof to provide maximum coverage.
A Modular GPS receiver can be placed in a location that is both easily accessible
and safe from theft and the weather. The antennas can be placed high on a
vehicle or vessel roof, clear of obstructions and able to deliver maximum
performance.
Rover receiver setup guidelines
For good rover operation, observe the following setup guidelines:
• Place the GPS antenna in a location that has a clear line of sight to the sky in all
directions. Do not place the antenna near vertical obstructions such as
buildings, deep cuttings, site vehicles, towers, or tree canopy. GPS rovers and the
base station receive the same satellite signals from the same satellites. The
system needs five common satellites to provide RTK positioning.
• Place the GPS and radio antennas as high as possible to minimize multipath
from the surrounding area. The receiver must have a clear line of sight to the sky
at all times during operation.
• GPS satellites are constantly moving. Because you cannot measure at a specific
location now does not mean that you will not be able to measure there later,
when satellite coverage at the location improves. Use GPS planning software to
identify the daily best and worst satellite coverage times for your location and
then choose measurement times that coincide with optimal GPS performance.
This is especially important when operating in the worst GPS locations. The
Trimble Planning software is on the Trimble SPS GPS Receiver CD included with
the receiver. You can also download the Trimble Planning software from the
Trimble website (
www.trimble.com/planningsoftware_ts.asp).