Ionospheric model correction for spaceborne GNSS receiver

This paper describes an ionospheric model correction for single-frequency GNSS receiver operated in low earth orbit. Various models have been proposed for removing ionospheric time delay, all of which were developed for GNSS receivers operating on the ground. For this reason, if the ionospheric model is applied to spaceborne GNSS receiver, the ionospheric model should be calibrated considering the characteristics of low earth orbit. The features of the characteristics are classified as the receiver altitude, single layer and the low elevation angle of receiving signal. Especially, considering receiver altitude and attitude maneuvering, there is a high possibility of receiving signals from negative elevation(-20 deg ~ 0 deg). The proposed ionospheric correction model is designed to reflect the above three characteristics. The performance of proposed ionospheric correction model is verified using position from pseudo-range of a Dubaisat-2 satellite that orbits the earth at an altitude of 600 km. For the given test case, a 57 % position accuracy correction is achieved in an orbit determination based on High-precision Orbit Propagator.