The SLR network from a QC perspective

Although it can be considered as a traditional if not classical technique, Satellite Laser Ranging (SLR) (still) plays a crucial role when it comes to assessing and monitoring a number of global aspects of System Earth: scale and origin of the terrestrial reference frame. A proper and timely monitoring of the performance of the network of laser stations is a prerequisite to provide an optimal contribution to the space geodetic community. In order to detect possible data problems at an early stage, a number of analysis centers perform a regular quality control (QC) of the SLR measurements on a variety of satellites. This paper addresses a number of issues relating to that: the development of the global network in terms of stations and their distribution, and the development of the (raw) data quality. The quality and consistency of reported range biases will be studied in this paper as well. Although the analysis done here covers the years 2004-2006 only, the results show an improvement in consistency for most of the QC centers, from about 30 mm in 2004 to about 20 mm in 2006 (total network) or from 25 mm to 15 mm (AWG core network). Two points of concern are the global coverage of the network of SLR stations and the decrease in the number of QC centers