FOA positioning improvement by satellite orbit error correction using reference station

The Frequency of Arrival (FOA) method is one way of achieving positioning using Low Earth Orbit (LEO) satellites. Positioning using LEO satellites can serve as an alternative to Global Navigation Satellite System (GNSS) in GNSS-denied environments. However, when using LEO satellites without accurate orbit information, FOA positioning accuracy is degraded by orbit errors. To address this issue, we propose a simple and effective method to correct these errors using a reference station. The reference station is installed at a known, static position and observes the same satellite as the user. By applying the correction data generated by the reference station, the user's FOA positioning accuracy can be significantly improved. We evaluated this method using real data from both GPS and Iridium-NEXT satellites. When using GPS satellites, the positioning accuracy improved from 36 km to 3.5 km. Similarly, when using Iridium-NEXT satellites, the positioning accuracy improved from 27 km to 3.8 km.