Laser Fuze Research Articles

FMCW Laser Fuze Structure with Multi-Channel Beam Based on 3D Particle Collision Scattering Model under Smoke Interference.

In the environment of smoke and suspended particles, the accurate detection of targets is one of the difficulties for frequency-modulated continuous-wave (FMCW) laser fuzes to work properly in harsh conditions. To weaken and eliminate the significant influence caused by the interaction of different systems in the photon transmission process and the smoke particle environment, it is necessary to increase the amplitude of the target echo signal to improve the signal-to-noise ratio (SNR), which contributes to enhancing the detection performance of the laser fuze for the ground target in the smoke. Under these conditions, the particle transmission of photons in the smoke environment is studied from the perspective of three-dimentional (3D) collisions between photons and smoke particles, and the modeling and Unity3D simulation of FMCW laser echo signal based on 3D particle collision is conducted. On this basis, a laser fuze structure based on multiple channel beam emission is designed for the combined effect of particle features from different systems and its impact on the target characteristics is researched. Simulation results show that the multiple channel laser emission enhances the laser target echo signal amplitude and also improves the anti-interference ability against the combined effects of multiple particle features compared with the single channel. Through the validation based on the laser prototype with four-channel beam emitting, the above conclusions are supported by the experimental results. Therefore, this study not only reveals the laser target properties under the 3D particle collision perspective, but also reflects the reasonableness and effectiveness of utilizing the target characteristics in the 3D particle collision mode to enhance the detection performance of FMCW laser fuze in the smoke.

Echo characteristics of pulsed lasers in non-uniform smoke environments.

This work establishes a pulsed laser backscattering echo signal model based on an improved semi-analytical Monte Carlo method. The developed model is applied in non-uniform smoke environments to mitigate the smoke interference of laser fuzes for ground proximity detection. The model considers variations of the photon step size according to the concentration of the smoke environment, and the computational speed is accelerated by implementing an improved semi-analytical reception method. The proposed echo signal model is employed to investigate the effects of smoke-related parameters and laser detection system parameters on the backscattering echo waveform of smoke. Finally, the model is validated based on experiments. The results show that the intensity of the smoke backscattering echo and the emission pulse width approximately conform to a logarithmic relationship. Specifically, the echo intensity is positively correlated with the emission pulse width, and the ratio of the time between the rising edge and the falling edge of the echo signal is positively correlated with the pulse width. Meanwhile, the intensity of the smoke backscattering echo and the distance between the transmitter and receiver approximately adopt an exponential relationship. Herein, we describe the characteristics of a laser backscattering echo in a non-uniform smoke environment. The results can guide future research regarding laser fuze detection methods and strategies relevant for ground targets in smoke environments.

A Study on Accurate Ranging Method of a Dual-Wavelength Orthogonal FMCW Laser Fuze in a Complex Aerosol Environment

A Study on Accurate Ranging Method of a Dual-Wavelength Orthogonal FMCW Laser Fuze in a Complex Aerosol Environment

Research on Temperature Characteristics of Pulse Laser Fuze Drive Circuit

Research on Temperature Characteristics of Pulse Laser Fuze Drive Circuit

The Detection Capability of Laser Fuze in Fog, Mist, and Haze Using Monte Carlo Simulations

When choosing a laser wavelength for proximity fuze with high accuracy requirements, the weather condition is a considerable element. Hence, the paper developed a laser detection model in different conditions based on the Monte Carlo method to evaluate the detection capability. As the atmospheric attenuation is a function of the wavelength, there is a conception that the laser pulsed fuze with 1550 nm light suffers from less atmospheric attenuation than 785 or 850 nm laser in all weather conditions (Pratt, 1969). However, in foggy weather (visibility <500 m), the results showed that laser attenuation appeared to be wavelength independent, i.e. the wavelengths of 785 nm, 850 nm, and 1550 nm are equally all attenuated equally by fog. Furthermore, the simulations also allowed the prediction of transmission, as well as the effects of energy scattering and absorption. This paper can provide guidance and reference for the application of laser wavelengths in the laser fuze.

Underwater four-quadrant dual-beam circumferential scanning laser fuze using nonlinear adaptive backscatter filter based on pauseable SAF-LMS algorithm

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser fuzes. To overcome this issue, we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering algorithm. This enhances the algorithm loading capability of the fuze. In order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms, we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square (SAF-LMS) algorithm. We also designed an algorithm pause module to retain the original trend of the target echo peak, improving the time discrimination accuracy and anti-interference capability of the fuze. Finally, experiments are conducted with varying signal-to-noise ratios of the original underwater target echo signals. The experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than 31 dB, with an increase of up to 76% in extreme detection distance.

Small opening cascade synchronous scanning underwater laser fuze using an adaptive backscatter filtering method

To alleviate the problem of the low spatial utilization rate of underwater single-beam rotating scanning laser fuzes, a multi-beam rotating scanning fuze structure is proposed in this paper. It was used as a platform to study the interference mechanism of underwater pulsed laser backscatter, and Monte Carlo simulations were performed for typical detection situations of the underwater laser fuze. It was found that the interference echoes resulting from backscatter could even drown the actual target echoes and cause severe interference to the target identification of the fuze. To this end, this paper proposes an adaptive filtering algorithm called “VSS-DLMS” suitable for the fuze FPGA platform and simulated using echo data obtained by a real detection environment. The simulation results demonstrate that the algorithm can effectively suppress the backscattered signal of the pulsed laser in seawater and improve the signal-to-noise ratio of fuze detection.

A Target Classification Optimization Recognition and Information Extracting Method of Laser Fuze Detection System Based on Fuzzy C-Means Incremental Update and Neural Network

A Target Classification Optimization Recognition and Information Extracting Method of Laser Fuze Detection System Based on Fuzzy C-Means Incremental Update and Neural Network

Accurate Ranging of Dual Wavelength FMCW Laser Fuze Under Different Types of Aerosol Interference

Laser fuze has the advantages of high distance accuracy and strong anti-electromagnetic interference capability, but it is easily disturbed by aerosols, such as smoke, which hinders its detection performance and application. This article proposes the dual wavelength frequency-modulated continuous wave (FMCW) laser detection technology as a solution. Compared with the single-wavelength FMCW laser fuze, the detection performance and the target recognition ability are enhanced under severe interference. First, the principles of dual wavelength FMCW laser detection are analyzed, followed by a block diagram of the fuze system. Second, the single scattering attenuation characteristics of spherical aerosol particles in reaction to different wavelengths of laser beams are discussed, and the scale distribution and complex refractive index characteristics and laws of four typical aerosol particles, including soot, ocean, dust, and water soluble, are analyzed. Finally, the echo characteristics of 0.3- and 10.6- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> wavelength laser beams with or without a target are simulated and analyzed under the condition of typical aerosol heavy interference, and the spectral characteristics of the beat signal of the dual wavelength laser echo are obtained. According to this characteristic, a system for target recognition and distance determination using a dual-wavelength FMCW laser beam against aerosol interference is designed. The simulation results indicate that, in the presence of severe interference, the proposed system can effectively distinguish aerosol interference from the target and realize the accurate distance of the target.

Spatial‐temporal scanning detection model and calculation method of laser fuze

AbstractTo scientifically evaluate the detection performance and detection ability of laser fuze, this study studies the double‐laser circumferential scanning detection method of laser fuze and its spatial‐temporal scanning detection model. According to the intersection relationship between projectile and target, the key parameters' calculation method of laser scanning detection is studied, and the spatial‐temporal scanning detection model and output signal model of laser fuze are established based on multi parameters in the detection system. Through calculation and analysis, the changing relationship between the laser detection ability under different laser beam incident angles, scanning frequency, deflection angle as well as other parameters and the laser echo under different deflection angles of laser fuze is discussed. The results show that when the emitted laser beam angle is fixed, the diameter of the detectable target becomes smaller and smaller with the increase of laser pulse frequency, that is, the detection ability of the laser fuze becomes higher and higher. At the same detection distance, the smaller the intersection angle of the missile and target, the stronger the laser echo power reflected by the target; when the detection distance and intersection angle increase, the detection probability of the laser detection system decreases significantly.

Pulsed Laser Ranging Techniques Based on Digital Signal Processing Methods for Proximity Fuze

Laser fuze systems play an emerging part in military technology bases nowadays. In the paper, a solution is developed to improve the accuracy of the laser rangefinder system in laser fuze without changing the hardware design of the digital signal processor. The proposed algorithm will combine real-time pulse processing techniques used in target range measurement. The new algorithm interpolates returned data using a relatively low sampling rate to a higher one. It applies a cross-correlation technique using high-resolution reference waveform models to restore the position of the super-sampled start and return pulses. Based on the Monte Carlo method and simulating the waveform in the noise environments, 100 trials were judged on the standard deviation of the range estimations. With the presentation of detection performance comparison results between range estimation algorithms of laser fuzes, this paper can provide guidance and references for the application in the proximity fuze.

Gaussian decomposition ranging method for laser fuze under cloud and fog interference conditions

Gaussian decomposition ranging method for laser fuze under cloud and fog interference conditions

Laser fuze anti-interference method based on array laser echo waveform feature recognition

Laser fuze anti-interference method based on array laser echo waveform feature recognition

ASSESSMENT OF TARGET DETECTION ABILITY FOR LASER FUZES IN FOG CONDITIONS

The article presents a method to evaluate the target detection efficiency of laser fuzes operating in foggy conditions. The evaluation model is built from: the distance equation of the laser system, the attenuation of the beam in two-way propagation, the disturbances affecting the system; the signal to noise ratio SRN has determined the detection probability of the receiver. The model was used to evaluate with wavelengths: 850 nm, 1000 nm and 1550 nm, when propagating in three different bad weather conditions. The results show that the most effective detection of the target when using a wavelength of 1550 nm in visibility in haze and mist conditions (visibility V &gt; 500 m). In fog conditions (visibility V &lt; 500 m), the above three wavelengths provide the same detection efficiency. The article provides the method and instructions for choosing the wavelength of the laser fuze.

Laser fuze specific target recognition based on grey system theory

Existing target recognition methods are difficult to implement on a low-cost and small-volume fuze platform. This paper proposes a rapid typical target recognition algorithm tailored to small sample sizes. A laser line scanning model is used to complete the target two-dimensional (2D) scanning, and the distance value of the target to be recognized is obtained to form a sample sequence matrix of the recognition algorithm. The ground recognition algorithm, which properly incorporates the ground effect and the uncertain direction of motion of the recognized target is used to reduce the influence of ground effect, a coordinated conversion model of the recognized target is established; a typical target recognition model based on grey system theory and fuzzy mathematics theory is established accordingly. The algorithm resolves the uncertainty in target recognition under lean information conditions. The recognition algorithm is proven capable of recognizing specific targets under small sample size. The results presented here may provide a reference for future low-cost laser imaging fuze target recognition applications.

Laser reflection echo signal detection and calculation under multi-attitude intersection

To improve the detection capability of laser fuze, this paper researches the laser echo signal detection method and echo power calculation method on laser fuze. From the multi-attitude intersection relation of projectile and target, we analyze the laser echo characteristics of target, set up the modeling of laser echo power by using the finite element meshing method. Taking into account the parameters of yaw angle and pitch angle and roll angle, we derive the target reflection laser echo power calculation function by combining the non-Lambertian and bidirectional reflection function of target's surface, establish the target detection probability calculation model. According to the established laser echo signal and echo power calculation function, we calculate the laser echo power and detection probability under the multi-attitude intersection conditions and different detection distances. Through simulation tests, the test result accords with the theoretical model.

Design of Photoelectric Amplification Circuit for Laser Fuze

A photodetection system based on the PIN photodetector was proposed in order to amplify the weak narrow pulse echo signals received in the laser fuze without distortion. The circuit model of this photodetection system includes a preamplifier circuit, a main amplifier circuit. Computer simulations were carried out in the MULTISIM and TINA environment, and the gain of the photoelectric amplification circuit was 119.9dB and the bandwidth was 89.46MHz. The simulation results show that the optoelectronic receiving system realizes the low-noise and high-gain broadband application, which meets the designed requirements.

Simulation method of pulse laser fuze echo in dust environment

Simulation method of pulse laser fuze echo in dust environment

FMCW Laser Fuze Multiple Scattering Model and Accurate Fixed-Distance Algorithm in a Smoke Environment.

In a smoke environment, suspended particles can scatter and absorb laser photons, making target echo signals extremely weak and difficult to extract and identify, which causes obvious difficulty in fixed-distance of laser fuze. In this paper, the multiple scattering model of frequency-modulated-continuous-wave (FMCW) laser fuze in a smoke environment was established. This model simulates multi-path propagation and multiple scattering of photons. At the same time, we use the correntropy spectral density (CSD) algorithm for accurate fixed-distance of FMCW laser fuze. The absolute error of distance does not exceed 0.15 m in smoke interference environment.

激光引信在防空导弹高效引战配合中的应用研究

The laser fuze can realize omnidirectional detection of missile targets through the circumferential multi-channel layout, its active-rotational-narrow pulse detection method can obtain the information about missile-target distance, miss azimuth angle and target type. At the same time, due to the characteristics of narrow beam and no side lobes, the fuze initiation zone has a small distribution area. All of these factors provide an important technical approach for efficient fuze-warhead coordination. Based on the analysis of the influence factors of air-defense missile fuze-warhead coordination, a fuze-warhead system scheme with eight-channel circumferential laser fuze was designed, combined with missile-target distance, miss azimuth, and target type. The fuze-warhead coordination simulation results in conditions of typical encounter parameters indicate that, the kill probability of single missile could be obtained to a maximum of 10% with the laser fuze information. It is useful for optimal design.