.SP3 File Extension
File Type 1Windows XP SP3 CD File
What is an SP3 file?
Data file that resides on a Windows XP Service Pack 3 (SP3) installation disc; uses the filenames WIN51IP.SP3 and WIN51IC.SP3; contains data that is used for the operating system installation.
File Type 2NGS SP3 File
.SP3 File Association 2
File created in the National Geodetic Survey (NGS) Standard Product #3 (SP3) format; saved in a plain text ASCII format and contains satellite orbit information; used for tracking GPS satellite orbits, but also supports non-GPS orbits as well.
The original SP3 format, called SP3-a, was extended to include additional information in the SP3-b and SP3-c formats.