Thales Navigation Z-Max System - Thales Z-Max Operation And Application Manual

not clean enough to produce centimeter-level positions. Therefore, GPS is not
effective in a dense forest.
This is not to say that GPS surveying systems can only be used in areas with wide-
open view of the sky. GPS can be used effectively and accurately in partially
obstructed areas. The trick is to be able to observe, at any given time, enough
satellites to accurately and reliably compute a position. At any given time and
location, 7-10 GPS satellites may be above the horizon and available for use,
although the GPS system does not require this many satellites to function. Accurate
and reliable positions can be determined with five satellites properly distributed
throughout the sky. Therefore, an obstructed location can be surveyed if at least five
satellites can be observed. This makes GPS use possible along a tree line or against
the face of a building, but only if that location leaves enough of the sky open to allow
the system to observe at least five satellites.

Thales Navigation Z-Max System

The Z-Max System is Thales Navigation's most advanced post-process survey
system. This modular system includes all the required components to perform post-
process GPS surveys. The Z-Max System is built around the Thales Z-Max dual-
frequency GPS receiver. Being a dual-frequency receiver (utilizes satellite signals on
both L1 and L2 frequencies), the Z-Max makes your GPS system more versatile and
productive compared to a post-process GPS system based on a single-frequency
GPS receiver. A dual-frequency system requires shorter observation times on point
for static surveys, requires less time to initialize, less effort to remain initialized during
kinematic surveys, and will maintain the highest level of accuracy even when
surveying points are separated by 50 kilometers or more. There is no more advanced
post-process survey system than one based on the Z-Max dual-frequency GPS
receiver.
100 Z-Max Surveying System Operation and Applications Manual