Javad TRIUMPH-1, Operator'S Manual

Page: 76 / 162

Setup and Survey
Static Surveying for Base Stations
Collect Data
76
www.javad.com
4.3. Static Surveying for Base Stations
Static surveying is the classic survey method, well suited for all kinds of baselines (short,
medium, long). At least two receiver antennas, plumbed over survey marks, simultaneously
collect raw data at each end of a baseline during a certain period of time. These two receivers
track four or more common satellites, have a common data logging rate (5–30 seconds), and the
same elevation mask angles. The length of the observation sessions can vary from a few minutes
to several hours. The optimal observation session length depends on the surveyor’s experience as
well as the following factors:
• The length of the baseline measured
• The number of satellites in view
• The satellite geometry (DOP)
• The antenna’s location
• The ionospheric activity level
• The types of receivers used
• The accuracy requirements
• The necessity of resolving carrier phase ambiguities
Generally, single-frequency receivers are used for baselines whose lengths do not exceed 15
kilometers (9.32 miles). For baselines of 15 kilometers or greater, use dual-frequency receivers.
Dual-frequency receivers have two major benefits. First, dual frequency receivers can estimate
and remove almost all ionospheric effect from the code and carrier phase measurements,
providing much greater accuracy than single-frequency receivers over long baselines or during
ionospheric storms. Secondly, dual-frequency receivers need far less observation time to reach
the desired accuracy requirement.
After the survey completes, data the receivers collect can be downloaded onto a computer and
processed using post-processing software (for example, JAVAD GNSS Justin).
4.4. Kinematic (Stop & Go) Surveying for Rover Stations
In a kinematic, stop and go survey, the stationary receiver (Base station) is set up at a known point
such as a survey monument, or an unknown point. The receiver continually tracks satellites and
logs raw data into its memory. The Rover receiver is set up at an unknown point and collects data
in static mode for 2 to 10 minutes. When finished, assign the Rover to kinematic status and move
to the next survey point. At this point, and each subsequent point, the receiver is changed to static