The ILRS Contribution to ITRF2013 and the Status of Future ILRS Products

Abstract:

Satellite Laser Ranging (SLR) data have contributed to the definition of the International Terrestrial Reference Frame (ITRF) over the past three decades. The new approach used since ITRF2005 provides an opportunity to verify the intra-technique consistency and a comparison of internal procedures and adopted models. The ILRS contribution is based on the current IERS Conventions 2010 and our internal ILRS standards, with a few documented deviations. Since the Global Geodetic Observing System – GGOS identified the ITRF as its key project, the ILRS has taken a two-pronged approach in order to meet its stringent goals: modernizing the engineering components (ground and space segments), and revising the modeling standards taking advantage of recent improvements in system Earth modeling. The main concern in the case of SLR is monitoring systematic errors at individual stations, accounting for undocumented discontinuities, and improving the target signature models. The latter has been addressed with the adoption of mm-accurate models for all of our targets. As far as the station systematics, the AWG had already embarked on a major effort to improve the handling of such errors prior to the development of ITRF2008. The re-analysis for ITRF2013 extends from 1983 to the end of 2013. As in the case of ITRF2008, station engineers and analysts have worked together to determine the magnitude and cause of systematic errors that were noticed during the analysis, rationalize them based on events at the stations, and develop appropriate corrections whenever possible. With the completion of ITRF2013 the ILRS will next turn its attention to the development of new products that we can soon deliver to the community on a routine basis. This includes precise orbits, low-degree gravity field harmonics, and quality control of ground system systematics. This presentation will give an overview of the development and evaluation of the ILRS contribution to ITRF2013 and summarize the new future products, including sample results.