Thales Z-Max Operation And Application Manual page 265

When the rover system detects that it is not initialized, it will automatically execute the
initialization process. No interaction by the user is required to instruct the rover
system to initialize. The initialization process is dependent on several factors
including site obstructions, satellite visibility at both the base and the rover site, and
the separation (distance) between the base and the rover receiver.
For initialization to occur, the base and the rover RTK systems must be observing at
least 5 common satellites. If the number of common visible satellites is less than 5, or
if the either the base or the rover site is obstructed causing either system to see less
than 5 satellites, the system will not initialize. Either survey at a time when more
satellites are visible, or in the case of an obstructed site, move the obstructed receiver
system to a more suitable location.
The time required to initialize the rover system is also dependent upon the distance
between the rover and the base. The closer the rover system is to the base, the faster
the initialization process. As the rover moves further away from the base system,
initialization times will increase. If the base and the rover systems are observing at
least 5 common satellites and the base-rover separation is less than 15 km,
initialization is often instantaneous, i.e. less than 5 seconds. Once the rover system is
initialized, it will remain initialized as long as the rover receiver remains locked on at
least 4 satellites. If at any time after initialization the rover receiver does not maintain
lock on at least 4 satellites, initialization will be lost and the rover system will
automatically execute the initialization process again.
Receiver initialization is most crucial when you are ready to store the position of a
point of interest or about to stake out a point. If the rover system is not initialized when
a data point is stored, accuracy will be poor. If you are performing an Auto Point RTK
Survey (see page 244), the rover must be initialized to store an RTK position. Again,
the RTK SOLUTION LED on the Front Panel User Interface will display the current
state of initialization at any given time.
The RTK rover system must remain in constant communication with the base system
in order to compute accurate positions. As the rover system approaches the range of
the data link used, communication will begin to get undependable. When the range of
the radio system is reached and/or exceeded, the rover system will no longer be able
to produce accurate positions since it is not receiving the required data from the base
system. The COMMUNICATION LED on the front panel of the rover system will
provide you with information on the status of the data link. If the COMMUNICATION
LED is blinking green, then the incoming data quality is good. If the
COMMUNICATION LED is blinking red, then the incoming data quality is not good.
While there may be other reasons for poor quality transmitted data besides distance,
before doing extensive troubleshooting ensure the receiver separation is within the
range of the data link.
242 Z-Max Surveying System Operation and Applications Manual