Transcript 2 Years Experience with the Graz kHz SLR System

Moving to kHz Ranging
-
kHz Experiences in Graz
SLR 2000 Status & Issues
Herstmonceux kHz Status
Complete PC Board for kHz SLR
Others ?
Discussion, Questions, Plans …
Eastbourne, October 2005
kHz Ranging: Graz Experiences
2 Years Experience
with the
Graz kHz SLR System
Eastbourne, October 2005
2 years kHz Ranging:
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Fully operational since 2 years, day and night;
All satellites - from Champ to GPS 35 / 36 – are tracked;
Routinely 2000 Hz used (lower repetition rates would be
possible, but are never used ...);
Laser System is running very stable;
 Pump Diodes: Now  6000 hours, still perfect ...
Results: NOT ONLY (big) increase in return numbers;
 EVERYTHING has improved significantly:
 Stability; Single Shot RMS; Accuracy;
 Additional Outputs Results …
Eastbourne, October 2005
2 years kHz Ranging
Experiences in Graz (1):
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kHz SLR gives lot of returns (million !) – even with J lasers !
kHz lasers are DPSS (Diode Pumped Solid State) units:
 (... like changing from tubes to transistors   )
 They deliver very stable, very uniform pulses;
 They can deliver short pulses (10 ps in Graz);
 This results in 2-3 mm SS RMS:
 For CAL AND for – some – satellites (Grace, Champ..)
Eastbourne, October 2005
kHz Ranging: Grace SS RMS
kHz SLR Graz: Single Shot RMS
GRACE A & B, 2003 - 2005
5.0
4.5
10 Hz Laser
kHz Laser
Grace A
Grace B
SS RMS [mm]
4.0
3.5
3.0
2.5
2.0
1.5
1.0
2003.0
2003.5
2004.0
2004.5
2005.0
2005.5
2 years kHz Ranging
Experiences in Graz (2):
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With kHz, you get not only more and better returns,
but also additional information:
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You can „see“ single Retro-Reflectors;
With up to 100 k pts/NP: Single-NP-statistics ???
You can „see“ satellite spin and measure its parameters !
Eastbourne, October 2005
Ajisai Spin Determination
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AJISAI: Retro panels seen at
variable distances;
AJISAI rotates (0.51 Hz);
@ 10 Hz: Big Sat Signature;
@ kHz: Single Retro Motion
visible
Eastbourne, October 2005
kHz Ranging: AJISAI Spin
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AJI26907
Daylight
300 k pts
Eastbourne, October 2005
Ajisai Spin Determination
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AJISAI
10 secs of
full pass:
 11 k rets
15
Residuals [mm]
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AJI12217/05: 10 secs of residuals
10
5
0
-5
-10
Residuals [1-way mm]
-15
64708
64710
64712
64714
64716
64718
Seconds-of-Day
Eastbourne, October 2005
Ajisai Spin Determination
AJI12217/05: 2.5 secs of residuals
15
Residuals [mm]
AJISAI:
2.5 secs of full pass;
 3 k rets;
Spin: 0.51 Hz
10
5
0
-5
-10
Residuals [1-way mm]
-15
64708.0
64708.5
64709.0
64709.5
64710.0
64710.5
Seconds-of-Day
Eastbourne, October 2005
kHz Calibrations: Differences
Diffs between successive CALS
[mm]
SLR Graz: Routine - Calibrations 2005;
Each CAL: 10 000 Returns
6
Successive CAL Diffs [mm]
4
2
0
-2
-4
-6
2005
2005.1
2005.2
2005.3
2005.4
2005.5
2005.6
kHz Valibrations: Single Shot RMS
CAL RMS [mm]
SLR Graz: Routine - Calibrations 2003-2005;
10 Hz: 500 Returns; kHz: 10 000 Returns
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
10
0.5
0.0
2003
CAL RMS [mm]
Hz
2003.5
2 kHz
2004
2004.5
2005
2005.5
kHz Calibrations: Peak - Mean
SLR Graz: Routine - Calibrations 2003-2005;
10 Hz: 500 Returns; kHz: 10 000 Returns / CAL
Peak minus Mean [mm]
4
CAL Peak minus Mean [mm]
3
2
1
0
-1
-2
-3
-4
2003
2003.5
2004
2004.5
2005
2005.5
kHz Ranging: Graz Experiences
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High Orbit Satellites, e.g. GPS 35 / GPS 36:
 Difficult to track for most SLR stations;
 Low return quotes;
 Not many stations get daylight GPS returns …
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kHz: Also advantages for GPS 35 / 36 Tracking:
 Acquisition is faster, easier with kHz laser;
 More returns / NP from GPS than with 10 Hz lasers;
 Day and night: Very similar results;
Eastbourne, October 2005
kHz Ranging: GPS 35/36
GPS-35:
- Daylight Pass;
- 12 k pts remaining;
- Down to 47° Elev.
- 4.5 mm RMS
62
46
32
30
30
Mt Stromlo
McDonald
Herstmonceu
Yarragadee
Zimmerwald
Beijing 3
Changchun 7
Potsdam 12
Simosato 18
Maidanak 1 20
67
Koganei
129
Monument
95
155
Riyadh
Wettzell
215
357
Grasse
Matera
845
1000
800
600
400
200
0
Graz
kHz Ranging: GPS with 400 J
GPS 35: Average # of Pts/NP in 2004
kHz Ranging: Graz Experiences
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Additional Information / all presentations of the kHz Workshop 2004 in
Graz available at:
http://khzslr.oeaw.ac.at/presentations.htm
Eastbourne, October 2005
kHz Ranging: Graz Experiences
Conclusion: The kHz Poem ....
Kilo-Hertz is lot of fun !
At least if all the work is done 
It DOES make sense – you should NOT wait …
You should increase your firing rate !!!
Eastbourne, October 2005