You are here: Home USNO Earth Orientation GPS-based Products Ultras
The USNO websites aa.usno.navy.mil, ad.usno.navy.mil, aristarchus.usno.navy.mil, maia.usno.navy.mil, rorf.usno.navy.mil, and toshi.usno.navy.mil are undergoing modernization efforts. The expected completion of the work and return of service is estimated as 30 April 2020. Please submit a requirements form to the USNOPAO if the information you are seeking is not accessible via other means.
 

Ultras

Read Me documentation for USNO Ultra-Rapid Products

USNO ULTRA-RAPID PRODUCTS

  • Files available:

    • GPS-satellite orbit + clock files (IGS .sp3 format)

    • Earth-orientation files (IGS .erp format)

  • Each file provides 48 hours of solutions:

    • 24 hours of post-processed solutions

    • 24 hours of predictions

    • These files are also available via anonymous ftp at ftp://maia.usno.navy.mil/GPS/ultras/

  • File name indicates center date/time of 48-hr span

    • before date = post-processed

    • after date = predict

  • Frequency/latency: produced every six hours, available three hours after center epoch.

  • File names (by example):

    • usu15002_18.sp3: 48-hr orbit/clock file with center date GPS week 1500, day 2 (Tuesday), hour 18 (GPST)

      • general format: usuwwwwd_hh.sp3

    • Similarly, usu15002_18.erp

 

To learn more about these products, click here.

USNO Master Clock Time
Javascript must be Enabled