Chirp pulse radar system design to acquire monostatic and bistatic mode using transponder

Abstract

Interest in bistatic and multi-static synthetic aperture radar technologies is increasing in that they can observe various scattering characteristics compared to the monostatic synthetic aperture radar technology, which has been extensively studied. Monostatic and bistatic mode imaging can be integrated into one system. For this purpose, monostatic and bistatic synthetic aperture radar imaging can be implemented simultaneously using a radar system and transponder. However, the signal for triggering the transponder hits the clutter behind the transponder and the scattered response creates a ghost target in the bistatic image. To fundamentally solve this problem, a frequency down-conversion transponder is used to increase the separation between the clutter response signal of the transponder trigger signal and the bistatic mode acquisition signal generated by the signal re-radiated by the transponder. A C-band chirped pulse radar system was designed to transmit and receive with the corresponding transponder. Because conversion loss occurs due to frequency down-conversion in the transponder, a receiver structure with high reception sensitivity was designed for long-distance imaging operation. In this study, we present an algorithm that can implement synthetic aperture radar imaging in a long-range operational data acquisition structure using a designed chirped pulse radar system and a transponder testbed. The algorithm allows bistatic imaging post-processing to be performed with separated frequency channel signals that are frequency down-converted and re-radiated.