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Receivers are placed
directly on the ground. The bright white antenna tops provide a high
contrast photo target. (Black mats may be used for additional
contrast if needed.)
After receivers are
placed, a single button press turns on the receiver and begins data
collection. Three LED's provide feedback for power, number of
tracked satellites and data storage. Standard, rechargeable internal
batteries provide 6+ hours of data collection.
When the flight is
complete, each of the receivers is retrieved and connected to the
USB port on a PC (they mount as standard Flash Drives) and the
static observations are collected.
Either the included
CGO (CHC Geomatics Office) software or an
automatic online processing tool (like
NGS OPUS) is used to
determine the exact location of the primary X900S receiver and
'geodetically ground' the project. Then CGO office is used to
process the secondary receivers against the primary receiver
providing precise inter-receiver spacing.
Depending on the
distance to CORS, the project will typically have a geodtic X,Y,Z
placement accuracy of 2 cm. Inter-receiver spacing accuracy of 1 cm
is reasonable.
CORS Spacing in the
United States is sufficient to insure that 2-hour primary
occupations will always converge. Many areas will converge with
20-minute occupations, checkout
OUPS-RS Coverage. Secondary X20+
receiver spacing should be less than 4 kilometers. |
