Robust Wideband Waveforms for Synthetic Aperture Radar (SAR) and Ground Moving Target Indication (GMTI) Applications

High resolution SAR imaging and Ground moving target indicator (GMTI) radar are of critical value to modern intelligence surveillance and reconnaissance missions. High resolution SAR can be realized at the expense of wide bandwidth waveform. However, to achieve long dwells over a wideband width, often the operating frequency band can overlap with other co-band radars, and it becomes necessary to notch out those interference bands both in the transmit mode and the receive mode. Thus it becomes necessary to design wideband transmit waveforms with spectral notches to null out the co-channel interference while maintaining excellent pulse compression with good sidelobe properties. A solution to this problem is presented in this proposal. The new solution leads to poor range resolution and to compensate that, two new receiver design strategies to suppress the sidelobes are also presented here. For azimuth compression, the carrier frequency plays a crucial role in narrowband SAR. However, the use of wide bandwidth leads to a less well defined role for the carrier frequency resulting in poorer azimuth resolution. This fundamental problem is addressed here using a new approach that draws on recent results on non-linear sparsity based image processing methods.