A Cooperative SAR-Communication System Using Continuous Phase Modulation Codes and Mismatched Filters

• Published in: IEEE transactions on geoscience and remote sensing Vol. 61; pp. 1 - 14
• Main Authors: Chatzitheodoridi, Maria-Elisavet, Taylor, Abigael, Rabaste, Olivier, Oriot, Helene
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-01-2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Airborne radar; Airborne remote sensing; Algorithms; Codes; Communication; Communications; Communications systems; Computer applications; Computing time; continuous phase modulation; Engineering Sciences; Filters; Image enhancement; Image quality; Image reconstruction; Image resolution; integrated sidelobe level (ISL); joint SAR-communication system; mismatched filter (MMF); OFDM; Phase modulation; Physics; Radar; Radar imaging; Radar polarimetry; SAR (radar); Sidelobes; Spaceborne radar; Symbols; Synthetic aperture radar; synthetic aperture radar (SAR); Telecommunications; waveform diversity; Continuous Phase Modulation; Integrated Sidelobe Level; Waveform Diversity; communication system; Communications; Mismatched Filter; Synthetic Aperture Radar (SAR)
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2022.3233198

The electromagnetic congestion due to the continuous growth of spectral demand has been skyrocketing for the past years. Joint radar-communication systems are, thus, attracting attention as they can alleviate spectrum occupancy by using the same bandwidth to perform both applications. In this context, a cooperative radar-communication system, which is a specific category that uses communication codes to both transmit information and perform radar missions, can be considered. Continuous phase-modulated (CPM) codes are considered in this article in order to generate high-resolution radar images from airborne radar. Since mitigating the sidelobe level energy is essential for good image quality, we resort here to optimized mismatched filters (MMFs). A fast algorithm is proposed to minimize the computational time of these filters. Simulated data are generated, as well as resynthesized synthetic aperture radar (SAR) images, and reconstructed from real chirp-based data using CPM codes and MMFs. Their performance is evaluated using different comparison tools and shows that the use of mismatched filtering and different messages embedded in the phase of each transmitted code provides enhanced image quality.