IGS orbit combination solutions are available in three forms: ultra-rapid, rapid, and final. The ultra-rapid product, useful for real-time and near real-time applications, is archived at regular intervals four times per day; the ultra-rapid solution includes both observed and predicted satellite orbits. The rapid orbit combination is a daily solution available approximately 17 hours after the end of the previous UTC day. The final, and most consistent and highest quality IGS solutions, consists of daily orbit files, generated on a weekly basis approximately 13 days after the end of the solution week. All orbit solution files utilize the Extended Standard Product- 3 (SP3c) format.