Research On Space Target Of Ground-based Infrared Detection Technology

Ground-based photoelectric telescope has important significance for the surveillance of the spatial target.Imaging features can directly identify the functions,status and tasks of the space target.The use of visible light band detection systems for imaging of space objects mainly depends on the reflected light(scattered light)of sunlight on the surface of the measured object,but it is difficult to observe when the target enters the shadow region of earth.And there is a stronger skylight background and atmospheric turbulence during daytime.So it also limits the imaging detection of the target.Using infrared detection technology can extract many important information of space target,such as temperature.Temperature is an important parameter to determine the target state.The temperature field on the surface of orbital spacecraft reflects its internal working state and function conversion,etc.Especially when the spacecraft fails,the temperature field distribution will change abnormally.The emissivity is an important parameter of the object's heat radiation characteristics.When the space object is in orbit,the emissivity data such as surface emissivity is an important basis for its thermal control.Surface emissivity of spacecraft and its variation with wavelength and temperature.It can be used to detect and identify information on the surface material composition of unknown space targets.In addition to extracting the surface information of the target,infrared detection technology also has good environmental adaptability.The detection performance of infrared at night and bad weather conditions and the ability to recognize target camouflage is better than visible light.The detection of infrared method is passive detection,and the concealment is not easy to be interfered.Compared with radar systems,infrared system has many advantages.Such as small size,light weight,low power consumption and so on.So infrared detection technology has been widely studied and applied in military and civil defense fields.In particular,with the strong demand in field of military and video surveillance and the promotion of development of infrared material technology in recent years,infrared detection technology as a high and new technology will be more widely used in the future.However,infrared photoelectric system also has its own unavoidable disadvantages.For example,when the optoelectronic system is working,its internal optical components will generate strong radiation noise when working in a normal temperature environment,which has a great impact on the effective detection of the space target.For this radiated noise,the use of cold optics allows very effective suppression of thermal radiation generated by imaging terminal.Reducing the background radiation perceived by the detector to the values below,which the generated dark current can be ignored,thereby greatly improving the target.detection efficiency.In summary,infrared detection technology and infrared imaging terminal equipped with cold optics can develop new observation capabilities based on existing large-aperture optical telescope system for ground-based.Realize imaging detection of the space target throughout all day and provide space.Temperature and infrared radiation characteristic density distribution maps of the target provide favorable support for the operation status,failure analysis,and identification of unknown space targets for future space stations such as space stations.In order to improve the detection capability of ground-based optoelectronic systems for space targets,this paper combines the infrared radiation characteristics of space targets.Using the calculated atmospheric transmittance and sky background radiation parameters,the spectral transmittance of optical system,and the detector band response characteristics.A spatial-to-noise(SNR)model of the space target imaging in infrared band was analyzed by simulation.On this basis,the infrared K-band spectrum was selected to perform daytime observation experiments on ground-based photoelectric telescope to verify the relevant technologies.The experimental data shows that the optimal design of the system during daytime limit detection of 10.38 stars at a pitch angle of 30° is better than the non-optimized daytime detection capability of 2.07 stars.This study provides an important basis for all-day observations of space targets.Aiming at the large errors brought by the atmosphere to the target radiation measurement,an atmospheric correction measurement method based on the reference source is proposed.The atmospheric transmittance and observation path range radiation obtained by using this method are different from those calculated by traditional atmospheric software.Accuracy is improved at differente target temperature.In order to reduce the spurious radiation of the photoelectric system.The influence of thermal radiation of infrared imaging terminal own radiation on the detection background was analyzed,and the refrigeration technology of the infrared imaging system of ground-based photoelectric telescope was deeply studied.A cold optical infrared terminal was developed for infrared imaging terminal own thermal radiation.The optical components,filters,and other optical components of infrared imaging system were cooled below the low temperature of 80 K,effectively inhibiting the thermal radiation of the telescope infrared imaging terminal against the detection background.The developed infrared cold optical terminal has the advantages of strong mobility,convenient installation and debugging,long use time,easy upgrade and replacement.The development of this terminal has certain reference significance for the foundation of cold optical infrared technology.