1 / 13

System Operations

System Operations. Towards the 1-mm: A realistic goal ? A vision ? A myth ? ???. Eastbourne , October 200 5. System Operations: Accuracy. How to reach the 1 mm ACCURACY ? Is it possible ? How to reach the 1 mm STABILITY ? Is it possible ?

zach
Download Presentation

System Operations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. System Operations • Towards the 1-mm: • A realistic goal ? • A vision ? • A myth ? • ??? Eastbourne, October 2005

  2. System Operations: Accuracy • How to reach the 1 mm ACCURACY ? Is it possible ? • How to reach the 1 mm STABILITY ? Is it possible ? • Which developments are necessary ? Recommended ? • Is the 1 mm a realistic / achievable goal ? • Simple answer: • Yes, but we do not know WHEN  Eastbourne, October 2005

  3. 1 mm: What we need … • Good LASER: SSDPL (Solid State Diode Pumped) • Short Pulse Duration:  10 ps • Good Event Timer: • A032-ET (Riga): < 10 ps RMS, < 2 ps nonlinearity, kHz ... • Dassault Modules (Graz E.T.): < 3 ps RMS, < 2 ps nonlinearity • Good detector: C-SPAD, Time Walk Compensated; • Good satellites:  ZERO Signature; PLUS strong return signal ! • Grace A, Grace B, Champ: No sat signature, good signal • LARET-C: Zero signature, but weak signal Eastbourne, October 2005

  4. 1 mm: Needs a good laser … • UPGRADE THE LASER: • Switch to Solid State Lasers (e.g. kHz); • Excellent Pulse uniformity; • Excellent Stability (shot-to-shot, day-by-day); • Short Pulses (10 ps in Graz) => better accuracy; • We do not see any disadvantage ... • Change from „TUBES“ to „SOLID STATE“ !!! Eastbourne, October 2005

  5. 1 mm: Needs strong signals … • With a 10-ps laser, good ET, strong-signal /  zero signature sat.: • 2 – 3 mm Single Shot RMS precision; • With VERY strong returns (> 300 pe / return): 1 mm SS RMS • Measure Return Signal Strength of EACH return: • C-SPAD: Use Time Difference Comp. / Uncomp. Output • Select returns with > 300 pe only  1 mm RMS • In CALs to 4 km Retro Target: Routinely achieved; • Current project ongoing in Graz; results in Canberra expected October 2005

  6. CAL RMS: From 10 Hz to kHz Eastbourne, October 2005

  7. CAL P-M: From 10 Hz to kHz Eastbourne, October 2005

  8. 1 mm with flash lamp laser ? • Old 10-Hz-Laser system in Graz (but with E.T. etc.): • Peak-minus-Mean: about ± 2 mm variations; • Too big; => difficult to reach the 1 mm goal !!! • With new Solid State Laser (kHz): • Peak-minus-Mean: MUCH better, very stable !!! • about ± 0.3 mm variations only ... Eastbourne, October 2005

  9. 1 mm: Needs a good satellite … • Use Retros / panels WITHOUT satellite signatures !!! GRACE-A GRACE-B CHAMP ??? 2-3 mm SS RMS Eastbourne, October 2005

  10. 1 mm Accuracy / Stability • All previous comparisons: • From 10 Hz Flash Lamp to 2 kHz Solid State Laser • All other Equipment: Same ... • Event Timer (Graz E.T. / Dassault Modules) • Same C-SPAD; same other equipment .... • Conclusion again: Change from „TUBES“ to „SOLID STATE“ !!! Eastbourne, October 2005

  11. Laser Pulse Width and Accuracy • Wide range of pulse widths used in SLR: • 10 ps: Graz / kHz / Solid State Laser; • 35 –50 ps: Standard Lasers; Flash Lamp Pumped; • 110 ps: e.g. Herstmonceux Flash Lamp Pumped; • 300 ps: SLR 2000 • Any other ? • What is the „best“/„optimum“/„desired“ pulse width ? Eastbourne, October 2005

  12. Laser Pulse Width Selection • 10 ps: Present optimum; no reason for shorter pulses … • No significant contribution to overall systematics anymore; • Excellent for Single-Photon-Detectors; • Allowa to see – and to handle - Single Retros …. • 300 ps: Can be eye-safe at e.g. 50 cm dia, if < 150 µJ / pulse • Relatively big contribution to overall systematics; • 1mm goal for Lageos => difficult with SPE signals< • Satellite signature problem slightly increasing; • Less problems with LEOs / MultiPhoton Detection Eastbourne, October 2005

  13. MeasuringLaser Pulse Width • I have no idea how to measure it ... • But Jerry Wiant is doing it  Eastbourne, October 2005

More Related