International Laser Ranging Service

ILRS Station Qualification

When a new station applies to join the ILRS tracking network, the station must undergo a “data validation” process in order to assess the quality of its data and to insure that the overall performance of the station meets the ILRS Standards.

This validation process is also initiated whenever a station that is already part of the ILRS network makes a “significant” change to the hardware or software in their system's measurement path.* The station must work with the ILRS to insure that the quality of the data has not suffered and that there have been no unexpected biases or systematic effects introduced into the data produced after the changes have gone into effect. Furthermore, if a station (already part of the network) has not produced data for 90 days, any new data it eventually submits will be subjected to the same qualification process to avoid any systematic errors due to possible inadvertent changes or aging of equipment during the lengthy outage.

In order to efficiently implement this qualification process, the ILRS has instituted a data quarantine policy for stations under the aforementioned circumstances in order to ensure that only data of the highest quality are available to the user community. The instances when a station's data can be quarantined are as follows:

• if a station is new, joining the network for the first time;
• if a station has carried out major upgrades to hardware and/or software;
• if a station requests that the data be put into quarantine;
• if a station has not delivered any data for over 90 days.

* “Measurement path” includes, but may not be limited to, the telescope, telescope mount, telescope pad, optics, transmit and receive paths, transmit and receive electronics, laser, detector, timing equipment, calibration piers or internal calibration path, meteorological sensors, software controlling any of these systems, as well as fixed geometric and electronic delays. If there is a chance that the telescope has moved due to an upgrade or for any other reason, the data must also be quarantined and the System Configuration Indicator (SCI) and the Occupation Number (last 2 digits of the Site Occupancy Designator (SOD)) must be incremented. (See configuration files for information on the configuration file and SOD for background on the SOD.)