- 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.
SCOUT jobs can also fail due to a bad receiver clock.
If your job fails, you may try perfoming a quality check on your rinex file
by running teqc on it, and looking at the output clock drift statistics.
- 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.
- 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
- How can I get more help?
A SCOUT user's forum is available. Please post your questions there.
- 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.
- 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.
- What do the standard deviations represent?
The standard deviations represent the uncertainty of the positions, and are one sigma.