Laser Jamming Research Articles

Highly sensitive interferometry with strong anti laser jamming capability based on frequency shift optical feedback

With the proliferation of diverse laser equipment, the optical environment in which highly sensitive optical systems operate has become harsh and intricate. Mitigating laser jamming originating from the operational waveband is a challenging problem encountered by laser interferometric measurement systems. In this paper, we set forth a robust anti-jamming optical interferometry with high sensitivity. This method is based on frequency shift optical feedback, namely anti-jamming laser feedback interferometry (AJLFI). A rear-end pumping Nd:YVO4 microchip laser with bidirectional output channels is employed as the interferometric system source, and the photodetector is posterior to the laser cavity. This particular laser structure and the unique detector placement method from optical feedback interferometry make the laser cavity operate as a high-stop-band filter to filter out laser jamming in the operational waveband. In the AJLFI-based system we established, the jamming laser with a wavelength equaling that of the interferometric system suffers a notable attenuation of 44.8 dB. Concurrently, jamming laser falling within a range of ±10 nm from the wavelength of interferometric system gets an attenuation exceeding 44.43 dB. In addition, we set up the standard laser feedback interferometry(LFI)-based system and the Michelson heterodyne interferometry(MHI)-based system with the same experimental parameters as the AJLFI-based system to perform anti-jamming capability comparative experiments. In the experiments, a pulsed laser beam with a peak power of 1780.9 W is employed as laser jamming in the operating wavebands, which is precisely directed toward the target in conjunction with the probe light of the interferometric systems and scattered into the interferometric systems. The experimental findings demonstrate that the AJLFI-based system exhibits superior anti-jamming capability in both phase and amplitude measurements compared to conventional LFI-based and MHI-based systems.

Simulation study of smoke screen jamming laser terminal guidance projectile

Simulation study of smoke screen jamming laser terminal guidance projectile

Evaluation method of laser jamming effect based on deep learning

Evaluation method of laser jamming effect based on deep learning

Deceiving ability of typical natural objects used for false target in laser decoy jamming

Aiming at the application of natural objects false target in laser decoy jamming, its deceiving ability characterized by decoy airspace was calculated and analyzed. On the premise of full considering the reflection characteristics of target, the intensity of jamming-indicating laser, atmospheric laser attenuation coefficient, and other factors, the analysis model of decoy jamming ability for false target was established under the condition of suppression coefficient K (≥1). Furthermore, the effectual decoy airspace of common natural objects was analyzed under typical condition. The results show that the effective cheating airspace of false target is closely related to the type of targets, and the deceiving ability of vegetation, gravel and diffuse reflection objects is enhanced in turn under the same conditions. There exists a mirror reflection component that is much smaller than the diffuse reflection component in the decoy airspace of vegetation and gravel natural objects, and the variation of the incident angle of jamming laser has obvious influence on the distribution of effectual decoy airspace. However, there is no obvious trend change rule for the decoy airspace of vegetation targets with the incidence angle. The research results are instructive for the reasonable application of typical natural objects used for false target.

Outfield experiment of semiconductor laser jamming on color CCD camera

Outfield laser jamming experiment of color charge coupled device (CCD) irradiated by semiconductor laser was performed. The impact of incident power density I0 and the focus length f on laser jamming results was obtained. Laser jamming model of color CCD camera is set up, and theoretical proving and analysis on experimental results are completed. Laser jamming effects on color CCD camera irradiated by semiconductor laser is obvious, CCD surface appears obvious optical saturation and crosstalk phenomena, and optical saturation areas gradually enlarge with the increase of power density to target and the focus length f. Simulation results are basically coincident with experimental results, and it proves laser jamming model is correct. We argue that optical saturation phenomenon should be caused by laser diffraction effect, and the impact of the focus length f should be mainly due to laser energy truncated by the aperture. The conclusions have a reference value for color CCD in aerospace.

变焦彩色CCD成像系统的激光干扰实验

Out-field laser jamming experiment of varifocal colour CCD imaging system irradiated by semiconductor laser was done. Laser jamming effects of colour CCD imaging system with different focal lengths were measured. Laser jamming model was set-up, and theoretical proving and analysis on experimental results were completed. Theorical and experimental results show that laser jamming effect of colour CCD imaging system irradiated by 750 nm laser is obvious, and CCD surface appears obvious light saturation and crosstalk phenomena. In the same initial laser irradiating conduction, laser power truncated by the aperture gradually decreases with increase of focal length f, and light saturation area on the CCD surface gradually increases. When focal length f of colour CCD imaging system is 17 mm, light saturation area on the CCD surface is 0.33 mm0.29 mm. While focal length f of colour CCD imaging system increases to 120 mm, light saturation area on the CCD surface is 1.8 mm1.2 mm. Simulation results are coincident with experimental results, and it proves laser jamming model is correct. The conclusions have a reference value for colour CCD in the practical application.

准平行光干涉的激光干扰方案与实验研究

A scheme for laser jamming using quasi parallel light interference was proposed. On the basis of the interference theoretical analysis, the multi -beam quasi parallel light interference images and interference intensity maximum value of two beams, three beams and four beams were obtained by HeNe laser, and the interference images and the light intensity distribution were got by simulation. Both theoretical and experimental results show that the patterns of quasi parallel light interference images depend on beam direction angle. In certain direction angle, there is bright stripes or bright spots of interference in the middle of the interference field. The distance between interference stripes or spots is decided by the angle between two beams of light. When the value of the angle between two beams is no more than 0.5 mrad, the experiment data is consistent with the simulation data, and the interference intensity maximum is close to the result of theoretical maximum, that is the light intensity maximum of two, three and four beams of quasi parallel light interference are four, eight, fifteen times the size of the light intensity of single beam. The effect evaluation and the test of validity of laser jamming scheme were given.

Modeling and simulation of multi-color CCD detector under super-continuum laser jamming

Modeling and simulation of multi-color CCD detector under super-continuum laser jamming

NETD and SNR analysis of laser jamming inf rared imaging system

NETD and SNR analysis of laser jamming inf rared imaging system

高重频激光干扰制导武器建模与仿真评估研究

高重频激光干扰制导武器建模与仿真评估研究

单CCD彩色相机激光干扰模型及外场干扰实验

Out-field laser jamming experiment of single CCD colour imaging system irradiated by multi-wavelength laser( 750- 970 nm) was done. Laser jamming effects of colour CCD imaging system with different irradiating conditions were measured at 1. 3 km. Laser jamming model was set up,and theoretical proving and analysis on experimental results were completed. Theoretical and experimental results show that the jamming effect of laser on colour CCD imaging system is obvious,CCD surface appears obvious light saturation and crosstalk phenomena. The light saturation phenomenon is caused by laser diffraction effect. In addition,laser jamming effect and light saturation gradually enhance with the increasing of the laser power density to target. When the laser power density to target of single wavelength 750 nm laser is 4. 2 k W / cm2,the light saturation area of CCD surface is0. 88 mm × 0. 97 mm. When the laser power density to target of multi-wavelength laser is 20. 7 k W /cm2,CCD device appears the whole target saturation. The simulation results are coincident with the experimental results,and it proves that the laser jamming model is correct. The simulation results for far-field laser jamming show that the laser jamming effect gradually weakens with the increasingof laser jamming distance.

IR imaging seekers may be very resistant to laser jamming

IR imaging seekers may be very resistant to laser jamming

Quantitative evaluation of high repetition rate laser jamming effect on the pulsed laser rangefinder

Laser may cause disfunction or even damage to laser rangefinder. Based on evaluation rules of high repetition rate laser jam pulsed laser rangefinder, the principles of distance deception and blinding jamming were analysed and the jamming success rate was calculated. We also set up a calculation example for 100kHz repetition rate laser jam certain type rangefinder. The result showed that we can obtain jamming grade and success rate, accomplish the quantitative evaluation of the laser jamming effect.

基于小波能量和光斑尺寸的干扰图像尺度分析

The influence of laser jamming on CCD imaging system is introduced.The similarity between laser jamming image and background clutter is illuminated in the view of their influence on electro-optical imaging detection system.Aiming at the frequency characteristic of laser jamming image and combining with background clutter metrics in machine vision,a comprehensive image metric for describing laser jamming effect is proposed by taking advantage of the predominance of wavelet analysis,based on wavelet energy and spot size.The wavelet analysis on typical laser jamming images indicates that the approximation coefficients and detail coefficients will both increase with the raise of laser power;the laser spot in jamming image can be regarded as the approximation coefficients,and the laser speckle around the spot can be seen as detail coefficients,which is similar to the salt noise.Laser jamming experiment in the field of view and simulative calculation show that laser jamming can reduce the segmentation accuracy of Otsu method,and raise the false alarm probability of correlation method.The metric can avoid the weaknesses of spot metric and wavelet energy metric.Hence,it is able to reflect the performance of laser jamming on CCD imaging system in the field of view properly.

基于压缩感知的激光干扰图像尺度分析

基于压缩感知的激光干扰图像尺度分析

视场外激光干扰图像对目标获取性能的影响分析

Based on Night Vision and Electronic Sensors Directorate(NVESD) target acquisition performance(TAP) models,from the aspect of clutter impact on human-in-loop TAP and aimed at characteristics of laser jamming image out of the field of view,a modified TAP model is applied to analyze laser jamming image.Experimental results of laser jamming to CCD out of the field of view show that the method can reflect the influence of laser jamming image on search and detection probability.Hence,the validity of this method is verified.

Experiment Study on Laser Jamming CCD Detectors

In order to confirm laser jamming effect on CCD detectors, experiment study on laser jamming CCD detectors was accomplished on axis and off axis. Pixel saturation threshold and saturation power density threshold were measured. Jamming image on axis was processed with computer. The relation curve was described between laser incident energy and CCD saturation area ratio. Jamming image off axis was also processed with computer. The relation curve was described between laser incident angle and CCD saturation area ratio. The experiment result shows that laser jamming CCD imaging guidance weapons is feasible.

激光对红外热成像设备自动增益控制电路的干扰效果

Based on the analysis of the working principle of automatic gain control (AGC) circuit, the mechanism of laser jamming on AGC circuit is discussed, and the experiment of laser jamming on the AGC circuit of an infrared thermal imaging device is carried out. An analysis method which uses the change of regional gray scale to test the gain of AGC circuit is then proposed. Finally, a quantitative analysis is conducted on the experiment data, and the result indicates that, the persistent effective interference of laser on AGC circuit of infrared thermal imaging device can be realized, on condition that the pulse period of interference laser is less than the adjustment time of automatic gain.

激光干扰技术现状与发展及关键技术分析

激光干扰技术现状与发展及关键技术分析

激光干扰试验中光纤耦合效率与稳定性研究

激光干扰试验中光纤耦合效率与稳定性研究