Thermal/Structural/Optical Analysis And Thermal Control Technique Of Aerial Camera

As an important equipment to efficiently acquire ground information，the aerialcamera is widely used in military and civil field. With the in-depth application, theresolution of aerial photograph is required to be higher, which is why that how toimprove the imaging quality of the aerial camera becomes one of the importantsubjects for engineers. In most of the environment factors, temperature disturbance isthe major one to influence the imaging quality. Therefore, studying the effects ofdifferent kinds of temperature distributions on the optical system and designing areasonable and reliable thermal control system are significant to acquire highresolution ground images and raise efficiency of the camera.Combining with the structural and environmental characteristics of the aerialcamera, the effects of the different temperature levels and gradients on the imagequality are analyzed using the integrated thermal/structural/optical (TSO) techniqueand the thermal-optical sensitivity analysis method. Accordingly, the temperatureindex for high resolution images is determined. In response to the actual temperaturedistribution of the aerial camera, the preliminary thermal control system is designed,based on which, the experimental aerial camera is framed and the insulation structureis especially designed for improving the impact of passive thermal control.For researching on the thermal characteristics of the aerial camera, the thermalnetwork mathematical model of the experimental aerial camera is set up. The heatdissipation of optical system is analyzed through the model, according to which, theheating loops and heating power are optimized. The sensitivities of optical systemtemperature to the uncertain thermal network parameters are studied, and the keyparameters with the optimal ranges are settled down, based on which, the passivethermal control is optimized.The transient thermal experiments are carried out, and the construction of thethermal network model is corrected using the experiment data. The reliability ofexperiment results are evaluated by error analysis technique. The applications ofleast-squares procedure, Monte Carlo method and genetic algorithms in thecorrection of thermal network parameters are discussed, and the advantage of geneticalgorithms is affirmed.The thermal control strategies of flying condition and low-temperature condition are presented through the analysis of the optical system thermal inertia.The thermal control system is optimized, and the simulation is processed with thethermal network model. The thermal control experiment system is designed and theexperiment is carried out using the experiment aerial camera. The experiment resultsshow that the temperature of optical system is controlled at18.5℃~20.5℃underflying condition, and the temperature rises from-55℃to-20℃within one hourunder low-temperature condition, and the temperature gradient holds within theindex. The experiment results indicate the availability of the thermal networkanalysis and the rationality of the thermal control design.