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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: 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): 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): 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 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 AJI26907 Daylight 300 k pts Eastbourne, October 2005 Ajisai Spin Determination AJISAI 10 secs of full pass: 11 k rets 15 Residuals [mm] 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 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; 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 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