Block Varying PRI Design for High Squint Sliding-spotlight Synthetic Aperture Radar

The squint sliding spotlight synthetic aperture radar (SAR) will bring about an exponentially increased range cell migration (RCM), which could lead to a conflict between the receive window and blind ranges for conventional fixed pulse repetition interval (F-PRI). Continuously varying pulse repetition interval (CV-PRI) could avoid blind ranges, but the echo signal acquisition and processing is complex than F-PRI. Block varying PRI (BV-PRI) as a novel PRI change rule was proposed in this paper to meet the space-borne SAR requirement. Because the azimuth antenna can be design very long, the value of PRF and wide swath are not very large for high squint sliding-spotlight mode, which decides the receive window can be design very large and PRI could keep a fixed value during several degrees of squint angle. Compared with conventional fixed pulse repetition interval, BV-PRI avoid the overlap of transmitting and receiving pulses, which process and restructure the echo signal is easier than CV-PRI with a limited number of PRIs. Furthermore, an example is presented by typical SAR parameters and the azimuth direction results are reproduced. Feasibility of BV-PRI is studied and verified in the azimuth direction simulation.