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LO calibration rate discussion. UPC/BEC. Reference image. Hawaii. UPC analysis. Differences snapshot to snapshot. Tmeas-Tref. Thermal noise is huge!!. SEPARATING NOISE COMPONENTS. Calibrated visibility:. decimation schemas. interpolated to time meas from cal data. Differences.
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LO calibration rate discussion UPC/BEC
Reference image Hawaii UPC analysis QWG-5 ESRIN
Differences snapshot to snapshot QWG-5 ESRIN
Tmeas-Tref Thermal noise is huge!! QWG-5 ESRIN
SEPARATING NOISE COMPONENTS Calibrated visibility: decimation schemas interpolated to time meas from cal data Differences The visibility has thermal noise: then Error in geophysical signal Thermal noise component QWG-5 ESRIN
Does averaging cancel the LO phase error? (Tx+Ty)/2 averaging 0 to 40º incidence angles. Simulation: Vref+phase error 10min-2min 6min-2min Spatial structures appear both cross-track and along-track QWG-5 ESRIN
Same effect in real data Actual data with decimated calibration 10min-2min 6min-2min The structures are still present QWG-5 ESRIN
The LO-phase error induces structure in xi-eta 6min-2min Average of 126 snapshots of TBn-TB2 (actual data) 10min-2min QWG-5 ESRIN
Conclusions • LO phase drift produces non-random visibilities errors that translate to brightness temperature spatial structures in xi-eta. • Relatively small phase error (low standard deviation) may have impact on the image due to this systematic behaviour. • Simulation data confirms the experimental results. Spatial structures are expected to encounter in SSS retrievals due to imperfect LO phase error cancellation. QWG-5 ESRIN