Further progress to improve the accuracy of satellite laser ranging data: impact on geodetic height time series of removal of range-dependent systematic errors at some European stations

High precision satellite laser ranging observations to the geodetic spherical satellites are now available for almost five decades, and their analyses are critical to the ongoing realisation of an accurate terrestrial reference frame. Inevitably and importantly the ground-station technologies have improved considerably over time, such that systematic range-measurement errors are now for the major stations at the few mm level. Such hardware improvements, as well as improved analyses procedures instigated by the ILRS, have prompted a review of the measurements made mostly by a number of European network stations in the early 2000s that used time-of-flight equipment known to have systematic, range-dependent errors of up to 10mm. These timers were investigated at the UK Space Geodesy Facility, Herstmonceux in the early 2000s and the range dependencies measured against a highly accurate event timer; however, some of the implications of those results have not yet fully been utilised in data processing for ITRF realisations.In this poster we review this work and report on our new data analyses that include the range-dependent corrections, commenting on the impact on the quality of the stations’ height time series.