|
Nowadays using the ultraviolet (UV) radiation to image space objects has been a progressive direction for remote
sensing. On earth, the atmospheric window to pass the UV radiation is the wave band from 280nm to 400nm. In this gap,
it will be supposed to image for the UV detection. Previously, it had been the normal method to detect the UV radiation
by using silicon-based devices or photomultiplier tubes as key detectors, but they also had intrinsic shortcomings
sensitive to other wave bands, such as the visible or the short-wave infrared band, so the whole optical efficiency of the
system had been low. At the same time, it had been balanced in difficulty, among the Signal-to-Noise Ratio (SNR),
spatial resolution, and spectral resolution, using aforementioned devices. Hence a novel means of the UV push-broom
imaging for remote sensing was introduced in this project. Firstly, a new-style UV linear array detector was designed,
based on the GaN material sensitive to UV radiation from 300nm-370nm, 512-pixel, in possession of the domestic
intellectual property in China, and this UV detector was the first device using the technology to manufacture
GaN-base-512-pixel linear array detector successfully. It has virtues such as the UV radiation band for detection can be
controlled by different ingredients of the GaN-base material, so it isn't necessary to achieve the aim using special UV
optic film filters, and this new-type linear array detector will be flexible and high efficient to image actual objects for UV
remote sensing. Secondly, a UV prototype camera was completed, using the GaN-base-512-pixel UV linear array
detector to implement push-broom imaging, IFOV (500μrad), in nadir and limb view angle (14.67°), SNR prior to 1000
under the condition of a standard solar constant, and the structure of this camera was introduced, including system
characters, optics, electronic modules, and so on. Thirdly, UV images to the actual outdoor objects had been achieved for
the first time. Not only the quality of UV push-broom images was good, but also all parameters of the camera were well
fulfilled. The new-type UV imaging technology using GaN-based linear array detector for push-broom was successfully
validated. In future, this technology will be applied for the marine oil spills pollution detection, preparing for UV
imaging remote sensing under the aviation or the space platform, and it will be carried out from the medium to high
spatial resolution. Besides, it will be applied for the deep space probe or the ozone opacity detection, and etc. In
conclusion, it is significant to the UV remote sensing development.
|
