Subject: [SLR-Mail] No. 1077: MyStationPerformance.Com Phase I
From: V. Husson, ILRS CB <Husson, Van <Van.Husson@honeywell-tsi.com>>

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SLR Electronic Mail          2003-04-18 22:59:00 UTC           Message No. 1077 
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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: &#8221;Husson, Van&#8221; <Van.Husson@honeywell-tsi.com> 

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