Polar to Cartesian Interpolation Algorithm

The registration of the ISAR (Inverse Synthetic Aperture Radar) signal in a two-dimensional (2D) polar grid and its interpolation to Cartesian coordinates is a problem while for image reconstruction a fast Fourier transform (FFT) is required. Normally, this ISAR problem is not considered due to short length of the synthetic aperture and comparably small sizes of the targets. The present work is intended to fill in the gab in the literature in respect of polar interpolation of the ISAR signal. For this purpose, ISAR signal formation with polar to Cartesian interpolation is analytically described and graphically illustrated. LFM (Liner Frequency Modulation) ISAR signal model is used to derive the main polar to Cartesian transformation equations.