GPS and GLONASS Satellite Transmit Power: Update for IGS repro3

Knowledge of the GNSS satellite transmit power is a prerequisite for the computation of antenna thrust caused by the transmission of navigation signals. Antenna thrust mainly acts in radial direction, depends on the satellite mass and the transmit power (Milani et al., 1987) and can reach up to 3 cm for current navigation satellites (Steigenberger et al., 2018). The received power of GNSS signals on the Earth surface can be measured with a high-gain antenna. The equivalent isotropically radiated power (EIRP) can then be obtained by correcting these measurements for freespace and atmospheric losses along the propagation path between satellite and ground antenna. The transmit power can be estimated from the ratio of the measured EIRP and the satellite transmit antenna gain. This report provides an update of the GPS and GLONASS satellite transmit power values presented in Steigenberger et al. (2018) as basis for the 3rd reprocessing campaign of the International GNSS Service (IGS; Johnston et al., 2017). Measurements with DLR’s 30 m high-gain antenna in Weilheim (Germany) of newly launched GPS and GLONASS satellites as well as assumptions for spacecraft without transmit power estimates are presented. Up-to-date transmit power values are included in the IGS metadata SINEX file available at the website of the IGS multi-GNSS pilot project: http://mgex.igs.org/IGS_MGEX_Metadata.php.