9:00 System
Operations Chairs:
G.
Kirchner
& W. Gurtner
This session will focus on two main points:
a) Global station performance items;
b) Accuracy items.
Proposed topics within these 2 frames are:
- How to improve global station performance ?
- How to upgrade stations for daylight ranging capability ?
- Progress since last workshop ? (... or why not ??? :‑( )
- Monitoring system / performance / temperature effects;
- Which develeopments are necessary for 1 mm STABILITY, 1 mm ACCURACY ?
- How important is laser stability in reaching this 1 mm ? kHz / solid
state technology ?
- Limits / requirements / goals for laser pulse width ?
- Automation: Does it effect / improve data quality ?
10:30
Tea Break
11:00 System
Operations (cont.)
12:30
Lunch
13:30
Daytime and HEO Ranging Chairs: U.
Schreiber & J. Luck
- What operational and signal
processing
techniques would improve daylight and extended
range (GPS) ranging?
- What
problems
do stations
face when operating in the daytime? Can stations
observe stars and the
laser beam in the daytime?
- How
successful
are stations at observing HEOs?
14:30
Timer
Linearity and Development Chairs:
F. Pierron & P.
Gibbs
- What
timer limitations are there when
approaching
1 mm observations?
- What
investigations have there been
into the linearity of interval timers?
- What
experiments have stations
preformed using movable targets to
investigate their timers?
- What
experiences have sites had
using event timers? What
developments have been made in the
technology?
There are 2 main
areas
where timing devices can introduce errors in the
data.
1) Non-linearities over a short
range. Eg
the SR620
shows in the manual a non-linearity over 11ns (90Khz).
This only adds
jitter to the satellite observations but can produce
and error in the
calibration as you are measuring a constant range.
2) Non-linearities over the full SLR
range (0-150ms).
Test
1
If possible could you do checks against a movable
calibration target.
What we would like is for stations to take a
calibration,
move
the target by some small amount (say 10cm) and then do
another
calibration. This should be repeated as often as is
possible * even
just 2 or 3 measures would be useful. If your timer is
linear you
should see a change in calibration equal to the
movement of the target.
For most of us the calibration range we measure
(cables,optics and
target distance) is a random timer range and it
is important
to
verify that we get the same calibration value whatever
total range we
measure.
Test
2
Could any stations with access to more than 1 timing
device make
simultaneous readings at a number of different ranges
using all their
timers. By splitting the signall to start/stop and
taking readings you
should get a series of readings which have a constant
difference
against range if your device is linear.
We would also welcome presentations on any other
investigations that
have been carried out on linearity and accuracy of
timing devices as
well as any news on new timing devices.
15:30
Tea
Break
16:00
Quality
Control P.
Gibbs
& M.
Wilkinson
- What quality requirements are
necessary
to reach 1 mm stability?
- What errors are found by the
Data Centres
in station data?
- What are the minimum
requirements for
data submission? How can these be checked at the
station before the
data is submitted?
- What consistency checks do sites
make of
their own data?
- How severe should stations be in
their
rejection criteria?
- What track selection criteria
should
stations use to select data to form Normal
Points? Which is
better, Orbit or Polynomial selection?
What are the
conditions in
the forming of a Normal Point?
Request to Analysts
Could
we have a list of the common errors
encountered in SLR NP data so that we can
summarize these in the
session and try to encourage stations to check
their data before it
goes out.
Questions
to
the Stations
Observing:
- Do you have any energy
monitoring?
- Do you have any energy
control?
If
No to the above do you have any plans in the
future?
Calibrations:
- Do you control the energy?
- Do you monitor any changes in
calibration?
- Do you have more than one
target for
comparisons?
Reductions:
- How is your initial data
selection made?
do you use orbit or polynomial fits?
- Can you reject parts of the
pass?
- What error checking is carried
out.?
Post
Reduction:
- Do you look at any of the
following: Analysis reports? Short
arc? Long arc?
Please
give
brief details of any QC carried out by your
station not covered in
above.
17:15 Software
Comparisons P.
Gibbs
- To
include New or innovative software that would
be useful to the SLR
community. This could include automatic
scheduling, predictions,
realtime , energy monitoring, track detection,
automatic reduction
processes and QC.
- For example we
have had to rewrite
our prediction software to cope with KHz
system. It has meant we have
smaller prediction files which are
easier to handle , more
versatile than our previous method and give
better predictions.
- To
Verify that all stations are being consistant
in their NP processing.
To this end I would ask any stations that wish
to be included in this
process to send me the input file(1) and
resultant NP file(2) for a
Starlette,Lageos and Etalon pass. Can you
please send the plain text
files to slr@slrb.rgo.ac.uk and label the
subject NP test
file
1 and NP test file 2.
18:00
End
Evening
ILRS
Governing Board Meeting
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