ИСТИНА

Numerical simulation of reflections of navigational space-borne radio beacons from undulating sea surface is performed at the main frequency of the Global Positioning System (GPS) L1 (1575.42 MHz). Electromagnetic field has been simulated with the Finite Difference in Time Domain (FDTD) technique for different model spectra of the sea waves (2D simulation code for s-polarized waves). Impact of the surface waves on the mean sea level estimate at the monitoring station location is investigated. Random and systematic errors, in particular related to partial shadowing of the undulating surface at low grazing angles of the sounding wave coming from a GPS beacon, are evaluated and estimated. Approaches to mitigation of the observational errors using auxiliary support data, including local sea waves spectra recorded in situ, context images/footage video of the surrounding aquatory, local weather conditions (wind speed and so on) are discussed.