Our Precise Science Orbits (PSO) of LEO satellites are estimated in a post-processed reduced-dynamic approach with a set of consolidated models. The minimum latency of the PSO product is about three weeks.

The onboard GPS data are processed in 30 h batches, with 6 h overlap between the adjacent orbit arcs, which is from 21:00 on the previous day to 3:00 on the next day. The PSO products are delivered without these overlaps and consist of the central 24 h part.

Carrier phase integer ambiguities are resolved using a dedicated algorithm based on a batch estimation of float ambiguities using the uncalibrated phase delay product.

The flowchart of LEO precise orbit determination is shown in Figures 1.