Abstract:The current status and development trend of passive early warning systems at abroad are presented. The passive early warning systems include infrared early warning systems, ultraviolet early warning systems and opto-electronic early warning systems. The key technologies and performance of various early warning systems are summarized. The development trend of early warning systems is analyzed. Particularly, the multispectral early warning systems containing multiple passive detection technologies are forecasted.

Abstract:A FPGA-based infrared horizon sensor system is presented. In the system, an uncooled infrared focal plane array is used as the detector and a FPGA is used as the main processor. The infrared horizon circle image is acquired in a dual-probe mode. Compared with the traditional infrared horizon sensors, this system has the features of miniaturization and low power consumption. It is suitable for micronano satellite platforms.

Abstract:Because of the limitation and limited usable range of traditional satellite in-orbit calibration methods, a new in-orbit calibration method based on an aerostat is proposed. In the method, the satellite is calibrated via the solar radiation reflected by an aerostat-borne mirror array. An in-orbit calibration model based on an aerostat is established and analyzed. The result shows that compared with the traditional in-orbit calibration methods, this method has the advantages of short atmospheric path, wide wavelength range and high calibration precision.

Abstract:Because of large amount of data and real-time characteristics, the processing of the signal of a laser Doppler velocity radar needs a high performance processing module. The Field Programmable Gate Array (FPGA) with advantages of high speed and parallelism can meet this demand. The implementation of signal processing for a laser Doppler velocity radar with a FPGA chip is presented. The data buffer, interference frequency filtering, 2-fold down-sampling, Fast Fourier Transform (FFT) and pulse accumulating etc of the FPGA are described. Finally, the performance of the module is analyzed and its test result is given.

Abstract:A portable UV camera for corona detection is presented. The camera uses a 320×256 pixel solar-blind UV FPA with the spectral range from 240 to 280 nm as its core detector. It has both a visible channel and a UV channel and can continuously operate for six hours after it is fully charged. The experimental results show that the camera can acquire clear UV images of the targets successfully and can be used to monitor UV signals in real time.

Abstract:A 4-channel detector imaging circuit based on a CCD47-20 and a CCD55-30 is designed. Because of long integration time, the system can implement high sensitivity imaging under the low-light condition. To choose appropriate driving devices, the driving circuit model for the detector is established and the driving requirements of CCD detectors are analyzed. After the noise characteristics of the detectors are analyzed, the circuit noise is suppressed by using the Correlated Double Sampling (CDS) and a reasonable filter. The noise interference among the 4 channel signal processing circuits is compared. The result is helpful to the reasonable PCB routing. This imaging circuit is used with a commercial camera lens and low noise images are obtained successfully under the low-light condition.

Abstract:Vacuum failure of a long-lifetime Dewaris mainly due to internal outgassing. The outgassing properties of the internal material in a Dewar are tested by using a Quadrupled Mass Spectrometer (QMS). The analysis result shows that the gas consists mainly of H₂O, CH₄, H₂ and so on.The model of outgassing properties is established according to the nonmetal outgassing theory. The result is valuable to material selection, optimization of outgassing techniques and Dewar exhausting.

Abstract:By using a continuous wave (CW) Nd:YVO₄ laser as the pump source, the quasi-phase match is implemented for a PPMgLN crystal at room temperature and a continuous intracavity optical parametric oscillator (OPO) is obtained. The optical parametric threshold obtained is only 3 W (808 nm). For the pump power of 5 W and the period of PPMgLN crystal of 31.5 μm, both continuous mid-infrared laser output with the power of 365 mW at the wavelength of 2.95 μm and the signal laser output with the power of 312 mW at the wavelength of 1.66 μm are obtained. The total light conversion efficiency is up to 13.3%. By changing the periods of the crystal, the wide band tunable output of idle light in the spectral range from 2.95 μm to 4.16 μm and that of the signal light in the spectral range from 1.43 μm to 1.66 μm are obtained. This mid-infrared optical parametric oscillator is simple in structure and high in efficiency. It will be one of the important methods for producing 3-5 μm mid-infrared laser sources in the future.

Abstract:In the field of infrared quantitative defect detection, the current theoretical methods simulate the defects mostly by using a rule model and then obtain the size of the detected defect by using an image comparison method or the first and second derivative of the image. All of these methods may bring about a large data error. The heat conduction among particles based on the particle theory is applied in quantitative defect detection for the first time. According to a simulated defect, the heat conduction equation is established. It provides a new idea for the quantitative infrared defect detection.