Picosecond event timing

K.Hamal, I. Prochazka, J.Blazej, Czech Technical University in Prague
U.Schreiber, Technical University of Munich, Germany
P.Sperber, University of Applied Sciences, Deggendorf, Germany

To upgrade the Satellite Laser Ranging (SLR) in terms of accuracy (single shot RMS, temporal and temperature stability, calibration bias) is in focus of most of the existing and future stations. The new concept of the Pico Event Timer (PET) has been worked out and implemented in a construction of the new timing device for SLR with picosecond timing resolution and stability. To proof the capability and flexibility of the PET for this purpose we have been installing the demo Portable PET (P-PET) into several existing SLR stations. Collecting data in Graz, Wettzell WLRS, Wettzell TIGO, Bern, Herstmonceux, using 30 picoseconds to 100 picoseconds lasers, and C-SPADs we have found, that the satellite single shot RMS is reduced by a factor 50 % typically.

The SLR data in Graz show single shot precision estimate of 5 millimeters for Lageos satellite and 3 millimeters on ERS satellites and 1 millimeter on the ground target when ranging on a multiphoton signal levels.

The PET has been operating at these stations in the "stand by", so called Portable Calibration Standard (PCS) configuration demonstrating just the capability to replace the existing station timing and gating electronics. The P-PET was found to be compact, simple to implement and operate, friendly to software, hardware and human environment, as well. In 1999 two additional PETs have been installed at Wettzell to WLRS and TIGO systems.

Related publications:

1. K.Hamal,I.Prochazka, Picosecond Event Timer for Millimeter Laser Ranging, Proceedings of the 23rd General Assembly Meeting of the European Geophysical Society, Nice, France, April 1998, published in Annales Geophysicae Supplement, Vol. 16, 1998
2. G.Kirchner, F.Koidl, J.Blazej, K.Hamal, I.Prochazka, Time Walk Compensated SPAD: Multiple Photon Versus Single Photon Operation, Proceedings of the European Symposium on Aerospace Remote Sensing, published in SPIE 3218-07, 1997
3. K.Hamal, I.Prochazka, J.Blazej, Pico event timer based portable calibration standard for satellite laser ranging, EnviroSense, EurOpto, Munich, Germany, June 14-18, 1999