| Date: | 2003-04-18 22:59:00 | |
| Sender: | V. Husson, ILRS CB <Husson, Van <Van.Husson@honeywell-tsi.com>> | |
| Subject: | [SLR-Mail] No. 1077: MyStationPerformance.Com Phase I | |
| Author: | V. Husson, ILRS CB | |
| Content: | ******************************************************************************** SLR Electronic Mail 2003-04-18 22:59:00 UTC Message No. 1077 ******************************************************************************** Author: V. Husson, ILRS CB Subject: MyStationPerformance.Com Phase I First, I would like to thank the dedicated work of my 2 HTSI co-workers, Paul (Jack) Stevens and Vo Hoai, for quickly making MyStationPerformance.Com a reality. Also, thanks to P. Gibbs and W. Gurtner for their review of this phase of the project. This is a description of the 1st Phase of MyStationPerformance.Com. The URL for MyStationPerformance.Com is: http://ilrs.gsfc.nasa.gov/stations/MyStationPerformance/ MyStationPerformance.Com has been developed to assist stations in their own performance evaluation. The concept for MyStationPerformance.Com was presented at the Washington DC 2002 Laser Workshop. We strongly encourage feedback and suggestions on MyStationPerformance.Com. So please send suggestions to the Central Bureau at cb@ilrs.gsfc.nasa.gov . Historically, LAGEOS has been the primary satellite used in station performance assessment. Therefore; the 1st phase/roll-out of MyStationPerformance.Com is based on LAGEOS (1&2). The following time series, since January 2001, are available for each system: Fullrate Observations Pressure / Pressure Differences Satellite and Calibration RMS System Delay To gain access to this information, select the site name from the navigation bar on the left. These charts will be updated each work day around noon Eastern Standard Time, so please come back often to review your most recent performance. Currently, there are 2 versions of each chart. The initial chart is 640 by 480 pixels in order to display properly in most browsers. If you click on this chart, it will expand and be more readable. The Fullrate Observation chart displays the sum of accepted observations based on this information provided in the normal point data records. A 30-point running average trend line is displayed to help in trend identification. Fullrate observations are dependent upon may factors (i.e. seeing conditions, detector threshold settings, etc). There may be seasonal trends in these results just due to weather patterns. The Pressure / Pressure Differences chart displays the atmospheric pressure in millibars from the 1st normal point in each LAGEOS pass segment. Many sites have seasonal trends in the barometric pressure. Global weather patterns (e.g. El Nino/El Nina ) do influence long term barometric pressure trends at the few millibar level. The pressure difference, displayed on the right hand scale, is the maximum difference between any 2 normal points from a given pass segment. A constant pressure difference of zero implies, for that particular site, that pressure is only measured once per pass. Excessive pressure differences (greater than 2 millibars) may indicate an error in the measurement. The Satellite and Calibration RMS chart displays the LAGEOS RMSs and their associated calibration RMSs which were extracted from the normal point header records and converted from picoseconds to millimeters. There are still a few sites which do not provide calibration RMS values in their normal point data. Calibration and Satellite RMS trends should be stable over time assuming no configuration changes have been made. Typically calibration RMS are a few to several mm lower relative to LAGEOS RMSs. An obvious symptom of a calibration problem is if the calibration RMS is greater than the LAGEOS RMS or if there is a change in the calibration RMS, and not a corresponding change in the LAGEOS RMS. The System Delay chart displays the system delay, in nanoseconds, from each LAGEOS header record. A dramatic change in system delay is probably due to an equipment change/configuration change. Unexplained changes in system delay need investigation. Small drifts in system delay can be influenced by temperature changes. From: ”Husson, Van” ******************************************************************************** |