12,257 research outputs found
A review of RFI mitigation techniques in microwave radiometry
Radio frequency interference (RFI) is a well-known problem in microwave radiometry (MWR). Any undesired signal overlapping the MWR protected frequency bands introduces a bias in the measurements, which can corrupt the retrieved geophysical parameters. This paper presents a literature review of RFI detection and mitigation techniques for microwave radiometry from space. The reviewed techniques are divided between real aperture and aperture synthesis. A discussion and assessment of the application of RFI mitigation techniques is presented for each type of radiometer.Peer ReviewedPostprint (published version
Iterative Time-Varying Filter Algorithm Based on Discrete Linear Chirp Transform
Denoising of broadband non--stationary signals is a challenging problem in
communication systems. In this paper, we introduce a time-varying filter
algorithm based on the discrete linear chirp transform (DLCT), which provides
local signal decomposition in terms of linear chirps. The method relies on the
ability of the DLCT for providing a sparse representation to a wide class of
broadband signals. The performance of the proposed algorithm is compared with
the discrete fractional Fourier transform (DFrFT) filtering algorithm.
Simulation results show that the DLCT algorithm provides better performance
than the DFrFT algorithm and consequently achieves high quality filtering.Comment: 6 pages, conference pape
Data compression techniques applied to high resolution high frame rate video technology
An investigation is presented of video data compression applied to microgravity space experiments using High Resolution High Frame Rate Video Technology (HHVT). An extensive survey of methods of video data compression, described in the open literature, was conducted. The survey examines compression methods employing digital computing. The results of the survey are presented. They include a description of each method and assessment of image degradation and video data parameters. An assessment is made of present and near term future technology for implementation of video data compression in high speed imaging system. Results of the assessment are discussed and summarized. The results of a study of a baseline HHVT video system, and approaches for implementation of video data compression, are presented. Case studies of three microgravity experiments are presented and specific compression techniques and implementations are recommended
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