Subject: [SLR-Mail] No. 13: SLR Graz: New Cal Target, Zero Range Bias From: Georg Kirchner / Franz Koidl, SLR GRAZ ******************************************************************************** SLR Electronic Mail 1996-04-19 12:49:00 UTC Message No. 13 ******************************************************************************** Author: Georg Kirchner / Franz Koidl, SLR GRAZ Subject: SLR Graz: New Cal Target, Zero Range Bias Dear colleagues, since beginning of our ranging activities in 1982, the SLR Graz used the same calibration target, in a distance of 385.802 m, for pre- and post-cals. On 1996-04-17, 6:00 UTC, SLR Graz switched to a new, very short distance, external calibration target; the effective distance is 1.742 m +/- 0.5 mm; the target is mounted within the dome, its position and distance is monitored to better than 0.5 mm. The laser energy for calibration is attenuated by PC-controlled switching of the laser amplifier delays; no additional glas/filter/attenuator/etc. is inserted for calibration at any stage. Instead of pre/post calibration for each pass, we now do a more extensive calibration in roughly half hour intervals, with linear interpolation of cal values, met values etc. for each return. IMPORTANT: ========= Any constant range biases, which may have been used in the past for Graz data analysis, should be ZERO now (hopefully) for all Graz data taken after this date. Kind regards ___________ | georg kirchner ^ franz koidl ---------------------------------( )--------------------------------- O From: kirchner@flubiw01.tu-graz.ac.at (Dr. Georg Kirchner 467351) ********************************************************************************