Synthetic Aperture Laser Imaging Radar (I): Defocused and Phase-Biased Telescope for Reception Antenna

A synthetic aperture imaging ladar demonstrator with Ø300mm antenna and changeable footprint

“…Pro. Liren Liu analyzed the optical characters of SAIL in space domain, and redefined the imaging azimuth and range resolutions in terms of the idea of optical imaging by a lens [6][7][8][9][10][11][12] . Directed by these analyses, we designed a multi-purpose SAIL demonstrator based on free-space optics to experimentally investigate and theoretically analyze the beam diffraction properties, antenna function, imaging resolution and signal processing algorithm of SAIL, besides, a laboratory-scaled SAIL system were built to verify the principle of design, and a primary experimental results were given [13] .…”

Inverse synthetic aperture ladar imaging algorithm for space spinning targets

“…It breaks through the limitation of the actual aperture and diffraction and overcomes the shortcomings of the traditional microwave imaging radar that cannot provide enough distance resolution for remote target and small target imaging, and overcoming the transmission [1]. The problem of high‐resolution and real‐time imaging of moving targets cannot be achieved by the unified imaging laser radar, and it is the only optical means in theory that can obtain centimetre level resolution at a distance of thousands of kilometres [2]. Therefore, space‐based ISAL imaging for space objects can meet the needs of high precision imaging and quasi‐real‐time imaging for space target surveillance.…”

A multi-purpose SAIL demonstrator design and its principle experimental verification

“…Liren Liu analyzed the optical characters of SAIL in space domain, and redefined the imaging azimuth and range resolutions in terms of the idea of optical imaging by a lens. [5][6][7][8][9][10] In this research, a synthetic aperture imaging ladar (SAIL) demonstrator is designed and being fabricated to experimentally investigate and theoretically analyze the beam diffraction properties, antenna function, imaging resolution and signal processing algorithm of SAIL. Such a multi-purpose SAIL demonstrator has the following design features: (1) A unified structure of telescope antenna has a big telescope of φ300mm aperture followed by a circulated duplex of a tunable secondary telescope to transmit an illuminating wavefront of needed spatial quadratic phase and of a defocused 4-f receiver to compensate the wavefront aberration of echo for a correct and efficient heterodyne detection, thus by tuning the secondary telescope not only the far-filed but also the near-field diffraction can be physically realized.…”