SOPAC GPS Orbits
Most orbit files can be found under the "products" data type using the data browser utility. Additional orbit files and related products are available by selecting "gfiles".
Orbits are also available via http or ftp:
- login: anonymous; password: your email address
- cd pub
- orbit directories: products (additional files in "gfiles")
SOPAC provides several GPS satellite orbit files and associated products. The "products" directory includes (note: YYYY=year, DDD=day-of-year, WWWW=gps weeek, D=day-of-week, Y=year in decade, HH=hour-of-day):
- sp3 precise ephemeris orbits in sp3 format (e.g., sioWWWWD.sp3.Z)
- earth orientation files (e.g., sioWWWWD.erp.Z)
- sinex files (e.g., sioWWWWD.snx.Z
- analysis summary files (e.g., sioWWWW7.sum.Z)
- clock files derived by a variety of analysis centers
Product naming convention
The first three characters represent the IGS analysis center (AC) and product category. When full AC (sio, jpl, cod, ngs, emr, usn, cod and gfz) names are given, the products correspond to final products. When the 3rd character is replaced with "r", it signifies the products are rapid products; when the 3rd character is replaced with 'u', it signifies the products are ultra-rapid products. The remaining characters after the first 3 characters indicate the GPS week and day of the week, in the form of WWWWD, possibly added with hour _HH. The following examples are for sp3 orbits; other types of products have the same naming conventions with a different extension, e.g., “.erp”, “.sum”).
- • xxx: final orbits, available within 10 days after the end of the UT day (e.g., sioWWWWD.sp3.Z)
- • xxr: rapid orbits, available after 17 hours (e.g., sirWWWWD.sp3.Z)
- • xxu: ultra-rapid orbits, provided every three hours (e.g., siuWWWD_HH.sp3.Z)
The "gfiles" directory contains gfiles (e.g., gpggaY.DDD.Z), where "Y" is the last digit of the year), which are orbit files that can only be used in GAMIT GPS data processing.
More information on precise orbits in sp3 (ASCII) format is available in the following publications: