Moving to kHz Ranging
Eastbourne, October 2005
- kHz Experiences in Graz- SLR 2000 Status & Issues- Herstmonceux kHz Status- Complete PC Board for kHz SLR- Others ?- Discussion, Questions, Plans …
kHz Ranging: Graz Experiences
Eastbourne, October 2005
2 Years Experience with the
Graz kHz SLR System
2 years kHz Ranging:
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
Eastbourne, October 2005
Experiences in Graz (1):
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..)
kHz SLR Graz: Single Shot RMS GRACE A & B, 2003 - 2005
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
2003.0 2003.5 2004.0 2004.5 2005.0 2005.5
SS
RM
S [
mm
]
Grace AGrace B
kHz Ranging: Grace SS RMS
kHz Laser10 Hz Laser
2 years kHz Ranging
Experiences in Graz (2):
With kHz, you get not only more and better returns,
but also additional information:
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
Eastbourne, October 2005
AJISAI: Retro panels seen at
variable distances; AJISAI rotates (0.51 Hz); @ 10 Hz: Big Sat Signature;
@ kHz: Single Retro Motion
visible
kHz Ranging: AJISAI Spin
Eastbourne, October 2005
AJI26907 Daylight 300 k pts
Ajisai Spin Determination
Eastbourne, October 2005
AJISAI 10 secs of
full pass: 11 k rets
AJI12217/05: 10 secs of residuals
-15
-10
-5
0
5
10
15
64708 64710 64712 64714 64716 64718
Seconds-of-Day
Res
idua
ls [m
m]
Residuals [1-way mm]
Ajisai Spin Determination
Eastbourne, October 2005
AJISAI:
2.5 secs of full pass;
3 k rets;
Spin: 0.51 Hz
AJI12217/05: 2.5 secs of residuals
-15
-10
-5
0
5
10
15
64708.0 64708.5 64709.0 64709.5 64710.0 64710.5
Seconds-of-Day
Res
idua
ls [m
m]
Residuals [1-way mm]
kHz Calibrations: Differences
SLR Graz: Routine - Calibrations 2005;Each CAL: 10 000 Returns
-6
-4
-2
0
2
4
6
2005 2005.1 2005.2 2005.3 2005.4 2005.5 2005.6
Dif
fs b
etw
ee
n s
uc
ce
ss
ive
CA
LS
[m
m]
Successive CAL Diffs [mm]
kHz Valibrations: Single Shot RMS
SLR Graz: Routine - Calibrations 2003-2005;10 Hz: 500 Returns; kHz: 10 000 Returns
0.00.5
1.01.5
2.02.53.0
3.54.0
4.55.0
2003 2003.5 2004 2004.5 2005 2005.5
CA
L R
MS
[m
m]
CAL RMS [mm]
10 Hz 2 kHz
kHz Calibrations: Peak - Mean
SLR Graz: Routine - Calibrations 2003-2005;10 Hz: 500 Returns; kHz: 10 000 Returns / CAL
-4
-3
-2
-1
0
1
2
3
4
2003 2003.5 2004 2004.5 2005 2005.5
Pe
ak
min
us
Me
an
[m
m] CAL Peak minus Mean [mm]
kHz Ranging: Graz Experiences
Eastbourne, October 2005
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 …
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;
kHz Ranging: GPS 35/36
GPS-35:- Daylight Pass;
- 12 k pts remaining;
- Down to 47° Elev.
- 4.5 mm RMS
kHz Ranging: GPS with 400 J
GPS 35: Average # of Pts/NP in 200484
5
357
215
155
129
95 67 62 46 32 30 30 20 18 12 7 3
0200400600800
1000
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kHz Ranging: Graz Experiences
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
Eastbourne, October 2005
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 !!!