Radio; Uhf/Vhf; Figure 2.3 Choke Ring Antenna For Severe Multipath Environment - ashtech Z-Xtreme System Manual

antenna is designed to function in the most demanding multipath environments.

Figure 2.3 Choke Ring Antenna for Severe Multipath Environment

Radio

The radio is the mechanism through which the base and rover GPS receivers commu-
nicate in the RTK system. Therefore, a radio is a component of both the base and
rover systems. As explained earlier, the base GPS receiver must transmit its raw data
to the rover GPS receiver in order for the rover GPS receiver to compute the vector
between the base and rover systems. The base system transmits the data and the
rover system receives the data using radios. The base radio is usually the larger of
the two since it must have transmit capabilities. It also consumes much more power.
The rover receiver needs only to receive the transmission. This requires much less
capability and power consumption. In some RTK systems, the rover radio is so small
that it is embedded inside the rover GPS receiver. Two distinctly different radio types
are available with the ZX SuperStation, one working in the UHF/VHF frequency
range, and another in the spread-spectrum frequency range. Distance requirements
between the base and rover systems will primary dictate which radio system to
choose.

UHF/VHF

If the intent is to perform RTK surveys with distances between the base and rover in
excess of 2 km, then a radio functioning in the UHF or VHF frequency range is recom-
10 Real-Time Kinematic Surveying