1)
Why did my SCOUT job fail?
SCOUT
jobs usually fail due to data quality issues or incorrect equipment
information submitted. SCOUT first attempts to obtain an a priori
position with a GAMIT utility module which computes the approximate
site position (at decimeter or meter level) using pseudo range. Once
the a priori position is obtained, 2 or 3 nearby sites are chosen to
form a small network which will be processed with GAMIT software
package in an iterated fashion. If data quality is poor, containing a
large percent of noises for example, no a priori position could be
calculated and the solution will fail. In the network processing,
GAMIT performs automatic data cleaning to fix cycle slips and remove
bad observations. If the observation session is relatively short, or
great many poor-quality data gets rejected, implying less usable
observation or extremely poor observation geometry, SCOUT will be
unable to obtain a reliable solution, or even fail. Sometimes the
data quality of the reference sites may be poor, or the reference
sites are too far away (resulting in long baseline lengths, thus
much less possible to form double difference and poor ambiguity
resolution), solutions can fail or have a higher chance of being poor
quality. The latter is indicated by high standard deviations of the
output values. Occasionally, network or computer system problems may
also cause processing failure.
While
SCOUT's minimum time span requirement is one hour, success rates will
increase if several hours of data are used.
2)
I processed two days of data for the same site, and the coordinates
do not match
This
may be due to various reasons. Obviously the data quality problem,
including very short data span, with the submitted site or the
reference sites may degrade the solution. Secondly the coordinates
from reference sites may have high uncertainties, meaning the network
is relatively free to move.
3)
Can you submit jobs in batch mode?
Software
provided by Martin Zumstrill at the Institute of Geodesy and
Photogrammetry, Technical University of Braunschweig, Germany is
available, but has not been tested at SOPAC. It is written in C# and
may require the installation of the .NET framework, available at
microsoft.com
4)
How can I get more help?
A
SCOUT user's forum is available. Please post your questions there. If you have problems posting, contact the webmaster.
5)
Why are my results different than those from OPUS?
SCOUT
and OPUS use different software to calculate positions, but the
results should be compariable at the cm level. However, data problems
discussed in #1 above can cause larger differences.
6)
At what point are the positions calculated?
Positions
are provided at the geodetic reference point, which is x meters below
the antenna reference point, where x is the antenna height provided.
7)
What do the standard deviations represent?
The
standard deviations represent the uncertainty of the positions, and
are one sigma.
