We study the possibility of extending a ratio method developed for real aperture radar to be used in a SAR, that can retrieve complex permittivities from a double bounce. We include the technical hurdles in the extension and then present the first results of a test using Airborne X-band data obtained by ONERA.
The capability of the time-frequency distributions (TFDs) to properly represent a single as well as multiple component signals in time and frequency permits the application of a new approach for interference excision in spread spectrum communication systems. In this paper, the instantaneous frequency estimate from the TFD is used to construct a finite impulse response filter which substantially reduces the interference power with a minimum possible distortion of the desired signal. The proposed technique is therefore a case of open loop adaptive filtering. Three-and fivecoefficient zero phase excision filters are considered. Closed form expressions of the improvement of SNR at the receiver correlator output using the TPD-based adaptive filtering are derived.
A wide class of short time Fourier Transforms (STFTs) or spectrograms can be generated by using an infinite-length analysis window corresponding to an impulse response of an W fdter. The cascade form realization of the analysis window allows concurrent generation of several STFTs with different trade-offs between temporal and spectral resolutions. The number of STFTs or spectrograms associated with the analysis window is equal to the number of the W filter singularities. The temporalspectral resolution diversity of the STFTs (Spectrograms) generated by any given "re is a function of the filter poles and zeros as well as their order of cascade. This paper focuses on multiple pole fdters and derives closed form expressions for their temporal resolution as a function of the pole position and multiplicity.
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