A Practical Target Radiance Estimating Method on Near-Surface Long-range

UV detection technology has great advantages for the effective detection of space targets. Due to the immediacy of the space detection target, it is difficult for the detection system to capture the target. When detecting the space target, it is necessary to select appropriate bands and set effective instrument parameters to increase the capture probability of the space target. At the same time, the field experiment process of space target detection by detector is relatively complex and difficult, so it is difficult to obtain such data. In the absence of test data, in order to make the UV detection system can set effective detection band, and ensure the good test and quickly obtain the radiation characteristics of the longrange target, simulation method is used in this paper. In an experimental way, in the case of unknown atmospheric conditions and composition, a model for calculating the near-surface long-range target radiance in UV band is constructed, which simplifies the radiative transmission process of the signal in the atmosphere. In this paper, the radiation of target in UV band is studied, and the mathematical model of radiation calculation is established. The research results have certain engineering application value. In the field test, it is difficult to determine the atmospheric transmittance between the camera and the target due to the lack of estimation of the atmospheric composition at the launch time, which makes it difficult to accurately estimate the radiation of the long-range target at near- surface in the test site. To solve this problem, the ultraviolet ( UV) band was divided into two parts, that were target band (240nm similar to 280nm) and background band (300nm similar to 400nm). By simulation, the estimating models of atmospheric transmissivity were separately established in the two bands. And then the long-distance target radiance was estimated only according to the distance for successive two times between the detector and target in a short time. Compared with the radiance of blackbody simulated, the relative error is about 9.87% in the target band, but only 0.11% in the background band. The research can provide technical support for UV detector to effectively detect the long-range target radiance.