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Proceedings with Extended Abstracts (single PDF file) - Radio ...

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PMSE is more easily interpreted as due to gravity wave modulation of the backgroundtemperature pro<strong>file</strong> [Chilson et al., 1997; Rapp et al., 2002]. Generally, we find thatthe GA-based phase calibration method has allowed the calculation of RIM echo powerimages <strong>with</strong> improved resolution and clarity.Radial Velocity (m/s)Range (km)8886848250−5Spectral Width (m/s)6Range (km)88868442820Restored RIM Image (dB)60Range (km)8886845550458209:25 09:30 09:35 09:40 09:45 09:50 09:55 10:00Time (UT)Figure 3: Radial velocity (vertical), spectral width, and calibrated RIM image.5 ConclusionsA novel GA-based phase calibration algorithm for RIM imaging applications has beenpresented. It was shown that this method provides robust initial phase estimation <strong>with</strong>fast convergence rates. The total power over a predefined window in the initial RIM imagewas used as the fitness function. By maximizing this total power as a function of phaseerror, the GA was able to provide convergent phase estimates <strong>with</strong>in 10–20 generations.After obtaining the phase errors based only on the optimization of the predefined window,these errors could be applied to the entire image, reducing the overall computationalburden. Preliminary PMSE images from the application of the RIM technique on theEISCAT radar were presented. Obvious image enhancement was obtained using the GAcalibration method to reveal the fine-scale structure in the PMSE.ReferencesChilson, P. B., P. Czechowsky, J. Klostermeyer, R. Rüster, and G. Schmidt, An investigationof measured temperature pro<strong>file</strong>s and VHF mesosphere summer echoes atmidlatitudes, J. Geophys. Res., 102 (D20), 23,819–23,828, 1997.Chilson, P. B., T.-Y. Yu, R. G. Strauch, A. Muschinski, and R. D. Palmer, Implementationand validation of range imaging on a UHF radar wind pro<strong>file</strong>r, J. Atmos. Ocean.Technol., 20 (7), 987–996, 2003.Holland, J. H., Adaptation in Natural and Artificial Systems, University of MichiganPress, 1975.Palmer, R. D., T.-Y. Yu, and P. B. Chilson, Range imaging using frequency diversity,<strong>Radio</strong> Sci., 34 (6), 1485–1496, 1999.40Rapp, M., F.-J. Lübken, A. Müllemann, G. E. Thomas, and E. J. Jensen, Small-scaletemperature variations in the vicinity of NLC: Experimental and model results, J.Geophys. Res., 107 (D19), 4392,doi:10.1029/2001JD001,241, 2002.141

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