Passive Radar Imaging by Filling Gaps Between ISDB Digital TV Channels

Integrated Services Digital Broadcasting-Terrestrial/Satellite (ISDB-T/S) signal, used in Japan as the digital television (TV) broadcasting standard, is exploited in this paper for passive bistatic radar two-dimensional imaging of stationary targets. A multifunctional system is developed with commercial-off-the-shelf antennas, low-noise block downconverters, and amplifiers. Several practical issues of using ISDB-T/S signals for imaging are highlighted. Ambiguity function analysis, accurate time delay estimation, inverse filtering, and local frequency correction are carried out. Multiple TV channels are combined to improve the range resolution. In order to reduce the artifacts caused by the frequency gaps among multiple TV channels, two low-rank matrix-completion-based algorithms are proposed. Experiment results with different targets validate the performance of the designed system and the proposed algorithms.