High-power flexible-polarization in-orbit-calibration satellite payload
A system of architecture, apparatus and calibration method is invented for high-power flexible-polarization payload for satellite communications. The system comprises onboard phase-tracked apparatus, flexible polarization mechanism, and in-orbit calibration method. The power combining and polarization performance of the phase-tracked payload is monitored on ground by measuring the cross-polarization discrimination (XPD) and/or axial ratio (AR). The high performance over the life is achieved by optimization of the XPD or AR on ground and adjusting complex gain of the transponders. The high-power flexible-polarization in-orbit-calibration payload may be applied but not limited to UHF, L, S, C, X, Ku and Ka-band high power satellite systems.
1. A method of calibrating a high-power flexible-polarization satellite payload system, the method comprising the steps of:
measuring cross-polarization discrimination and/or axial ratio performance of the system on the ground;
determining if the measured system performance is within a predetermined requirement range to stop calibration, if not, iteratively optimizing the measured system performance and determining if optimum system performance is reachable to stop calibration, and, if not, generating a command signal with compensation adjustments of respective phase and/or amplitude of in-phase and quadrature phase output signals; and
up-linking said command signal to the system via telecommand satellite link and repeating the preceding steps.
2. The method of claim 1 , wherein iteratively optimizing is performed using a search method.
3. The method of claim 2 , wherein the search method is one of a pattern search, a trust-region search, and a line search.