Ground and Inflight Calibrations of GPS Transmit Antennas

Kurzfassung

Between 2014 and 2023, Lockheed Martin and Boeing have gradually released factory calibrations of transmit antenna phase patterns for the currently active GPS Block IIR/IIR-M, IIF and III satellites. The presentation reviews the available calibration data, discusses their completeness and limitations, and describes a methodology for obtaining consistent sets of phase enter offsets (PCOs) and phase variations (PHVs) that enable comparison with existing IGS calibrations. Manufacturer PCOs for GPS IIF and III satellites derived in this manner show good consistency with the DTRF2020 frame, which inherits the Galileo scale from the Repro3 antenna model. Complementary to this analysis, a new LMB20 antenna model is presented, which offers phase patterns up to 20 degrees off-boresight angle for space users while keeping consistency with the IGS20 scale through block-specific or satellite-specific PCO adjustments.