Ultras

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.