Research On Spaceborne Hyperspectral Sensor Simulation

Hyperspectral remote sensing (HRS) has attracted much attention in recent years. Airborne HRS appeared earlier and has been used widely. With the progressing of technology and increasing of demand, the advantage of spaceborne HRS is gradually being realized. Compared with airborne sensors, spaceborne sensors are capable of doing earth observation without the restriction of terrain or weather. However, the cost is a limiting factor. For this reason, simulation technique emerged and has provided another way of development for spaceborne sensors. In this dissertation, a spaceborne hyperspectral sensor model is presented with the expectation of providing theory basis and technical support for spaceborne sensor design in China. Therefore, this dissertation researches in several aspects as following:Firstly, frequency domain analysis of optical system is studied in depth. Starting with the Fourier characteristic of optical system, optical transfer function (OTF) is investigated, which describes optical system in the spatial frequency domain. Optical chain for an integrated optical imaging system is also introduced. Besides, to deal with the digital detector of the sensor, OTF theory is extended and applied into discrete sampling system.Then, the spaceborne hyperspectral sensor is modeled according to its imaging principle. Considering the widely use of dispersion-type sensor as well as the bright future of interferometric sensor, simulation is performed based on these two types of sensor. Sensor system is modeled in the spatial frequency domain by exploring the OTF of each sub-module, in which the airborne hyperspectral image acts as the input. The sensor model consists of four parts: the optical system, the detector, the electronic system and the noise. OTFs of the first three parts are deduced in detail, and this step is the focus of the study.Finally, this model is realized on VC2005. With reference to the parameters of on-orbit sensors of the same or similar type, experiments are performed on the software simulation system. Experimental results validates that the interfero-metric sensor is much more excellent on the capability of optical system and detector. To support sensor system design, fidelity for hyperspectral data is introduced besides MTF, which gives a quantitative evaluation for the imaging capacity of sensor system, and subsequently, the basic principle of rationalizing and optimizing the parameters of sensor system is obtained.