NSGF prediction service ILRS 2005 Eastbourne 6 th
NSGF prediction service ILRS 2005 Eastbourne 6 th October 2005. Graham Appleby
Background • For about 10 years, IRVs generated by SGF for a large sub-set of the ILRS targets; • Originally long time-span (30 – 60 days) • Need/motivation: – as backup for daily ‘official’ ILRS predicts; – Long time-span predicts feed the SGF hourly rapid QC • Changed with other ILRS providers to daily production.
Multi-day IRV-based predicts as rapid QC
IRVs and satellites • IRV tuning process: – Provided tuning is fully applied, restituted orbit should represent the underlying precise prediction ‘quite well’: – for MEO and HEO, IRV-orbits follow prediction at m level; – For LEO, more difficult to force errors due to simple on-site force model into x and xdot; – So may be several m errors on top of how the predictions will noticeably degrade.
IRVs and satellites (2) • Predictions generated for: • Larets, Starlette, Stella, Envisat, Ajisai, Topex/P, Jason-1, Lageos (1+2), Etalon (1+2). • GPS 35+36, GLONASS (ILRS targets) – via predicted orbits from CODE.
cpf • Invited by Randy Ricklefs to test out new procedure; • Currently generate 3 -day predictions (body-fixed xyz) on daily basis as part of continuing IRV production; • Off-line tests of their use, for Lageos, in collaboration with Werner Gurtner, show good agreement with predicted alt, az, range from IRVs; • Currently distributed by email to Mc. Donald and Zimmerwald; • Will be implemented at Hx as time permits: • Motivation: – Better predictions, important for k. Hz; – Access to Ice. Sat for instance.
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