Intrapulse Effect Compensation Method for SAR Systems With Up- and Down-Chirp Modulation

The motion of the synthetic aperture radar (SAR) sensor during the transmit and receive events introduces a space-invariant polychromatic phase, known as intrapulse (IP) effect, which may degrade the impulse response function (IRF) if left uncorrected. A straightforward solution is already available in the literature to compensate for this effect for conventional SAR systems using a single waveform during the acquisition. However, there is currently no solution in the case the SAR system transmits an interleaved up/down sequence. If left uncorrected, besides the impulse response degradation in terms of azimuth and range resolution loss, additional azimuth ambiguities will appear. This letter proposes an azimuth-reconstruction-based approach to mitigate the IP effect for both single-receiver and multireceiver SAR systems with up- and down-chirp (UDC) modulation. The performance of the approach is demonstrated with point-target simulations.