The aim of this paper is to explore a high-precision, a wide range of a frequency discrimination technique, and to
study the application of this technique in the optical air data system (MOADS). To overcome the traditional
equipment's shortcomings of short velocity detecting range such as pilot static tubes and wind wane, this technique
can provide precision aviation data for various aerocrafts , without influencing pneumatic shape and performance of
aerocraft.
A tunable dual channel Fabry-Perot interferometer is used as a frequency discriminator in an airborne wind lidar
system. This new frequency discriminator has been proposed to overcome the exiting frequency discriminator
shortcoming. By adjusting the cavity length of interferometer, the speed of aerocraft can be detected and cut into
several dynamic range. By this way, the Doppler wind lidar system can detect atmospheric parameters at the
meantime, such as speed of aerocraft and temperature of atmosphere around the aerocraft, by analyzing the
information of Rayleigh backscattering light. There are three main contribution in this paper: the first is discussing
the basic theory of MOADS, calculational method and mathematic model of relative wind velocity between aircraft
and wind are put forward.; the second is the parameter optimization of the dual-channel Fabry-Perot interferometer
and the structure design of the interferometer; the third is the simulation of the performance and the accuracy of this
system. Theory analysis and simulation results show this method is reasonable and practical.
Diffractive optical elements (DOEs) are more flexible and powerful than tradition refractive-reflective optical
elements in correcting chromatic aberration of an optical system. In this paper the principle of correcting
secondary spectrum is described. In order to compare the effect of DOEs on correcting secondary spectrum, we
use CODE V to design a refractive telephoto system with different strategies: (I) All surfaces are spherical; (II)
One surface is diffractive in the system; (III) Two or more surfaces are diffractive (Multi-layer diffractive
system). It is found that multi-layer diffractive elements used in a telephoto system can easily correct
secondary spectrum without high dispersion glasses, such as calcium fluoride, at the same time high diffraction
efficiency and broad spectral bandwidth can be obtained. And the most important of all, the length of the
telephoto system can be shortened by about 30%, and the weight can be greatly cut.
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