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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