Research On Short-range Circular-viewing Detection Technology Of Pulsed Laser Fuze

Active protection system is a countermeasure system capable of intercepting the incoming hostile ammunitions.It significantly improves the survivability of strategic area and major vulnerable objects in battlefield,by actively detecting and intercepting incoming targets.Restricted by launching overload,space,power consumption and cost of conventional ammunition fuze,active protection systems both domestic and abroad mainly adopt expensive ammunitions,such as missiles,to intercept incoming targets.By solving key technologies of missile target intersection by active protection system using conventional ammunition,it has significant military value in domestic of changing the current situation of weak mastery of conventional ammunitions for active protection,upgrading the domain of the fuze technology could serve for,promoting the development of conventional ammunition fuze and improving the level of weapons and equipment.Research background of this paper is active protection conducted by medium and large caliber ammunition weapon system.Laser proximity fuze of conventional ammunition has been studied.Based on laser proximity fuze detection technology and laser fuze circular-viewing detection technology both domestic and abroad,theoretical problems and key technologies of single laser transmitting system and receiving system are studied with theory,modeling,simulation and experiments.Morever,miniaturization and low cost application of the fuze for the burst point control of conventional ammunition of active protection system were realized.Significant contents and innovation points are as follows:Models of missile target intersection and double scanning optimum detonating were established for the pulse laser circular-viewing detection system.Optimum value and matching rules of pulse frequency and scanning rotating speed of the motor were acquired by simulating and analyzing the effects of different parameters on detection probability.It could serve as theoretical basis for designing of the detection system.The influence of different parameters on the optimum delay time and the detonating azimuth has been analyzed.Meanwhile,optimum detonating strategy is proposed.More precise control theory is proposed to improve the maximum damage efficiency to the incoming target.Theoretical equation of echo power is improved with the consideration of the target surface characteristic and temporal-spatial distribution of pulse laser.The model is verified by experiments.The model and echo power equation are more widely applicable.It provides a theoretical basis for the study of the performance of pulsed laser circular-viewing detection.The influence of the surface characteristics on the ranging accuracy is uncovered for different detection methods.Cramer-Rao low bound for estimating the variance of range estimation was derived.The effects of various parameters on ranging precision were analyzed comprehensively.The ranging probability density functions of plane target for leading edge detection and constant fraction discriminator(CFD)detection were derived respectively.The influence of different parameters on the distribution characteristics of ranging system was studied by simulation and experiments.The simulation results show that CFD can effectively suppress walk error caused by different angles of rough plane.The theoretical basis for improve ranging accuracy is presented.Random threshold detection method is put forward with lifting wavelet denoising algorithm based on improved gradient particle swarm optimization.The detection probability and false alarm rate of single pulse fixed threshold,variable threshold and random threshold detection were simulated and analyzed.The results showed that in the condition of low Signal-Noise Ratio(SNR),false alarm rate can be constant,and the detection probability of the target detection could be effectively enhanced using random threshold detection.The improved lifting wavelet adaptive nonlinear denoising algorithm is put forward with the improved gradient particle swarm optimization.The simulation and experimental results show that the algorithm can make up inherent defects of random threshold detection and effectively improve the SNR of echo signal.It provides theoretical basis and implementation method for weak echo signal detection.The pulsed laser beam layout scheme was chosen.A pulsed laser circular-viewing detection system was designed,consisting of physical isolation type flat optical system,high-frequency and narrow drive power of laser fuze with adjustable pulse width,weak echo signal amplification circuit,the Pulse-Width Modulation(PWM)and Pulse Frequency Modulation(PFM)power for Avalanche Photodiode(APD)power supply,the high precision time interval measurement module and the designed magnetic detection module using rising edge detection algorithm.The prototype was built,and experiments were carried out.The experimental results show that pulse laser circular-viewing detection system has the advantages of miniaturization and low cost.Each subsystem was functioning well according to the principle of photoelectric information transmission.System electromagnetic interference was suppressed.The detection range of the system was more than 3m.The azimuth measurement error was within ±2°.Meanwhile,on the conditions of 34000g of shock acceleration,laser pulse circular-viewing detection system was completely functional.