基于双向反射函数的水下激光引信回波仿真方法

针对鱼雷激光近炸引信探测水下近场目标的需求,开展了水下激光引信回波蒙特卡洛仿真方法研究.结合水下激光引信探测特点建立水下目标回波的蒙特卡洛仿真模型.为了提高水中非朗伯目标表面回波仿真的准确度,推导了基于双向反射函数的光子反射方向概率分布,根据概率分布随机抽样光子反射方向.仿真了不同距离和入射角度条件下的水中目标回波信号.仿真结果表明:目标回波幅度随目标距离和入射角度的增大迅速下降,目标距离在6~12m内变化时,信号峰值动态范围为11.5dB;目标距离为8m,激光入射角在0~45°内变化时,信号峰值动态范围为9.2dB.为验证仿真方法的正确性,在水池中进行水中目标蓝绿激光探测实验,实验结果和仿真结果一致.研究成果可为解决传统蒙特卡洛方法在水中非朗伯面目标回波仿真中的适用性问题及水下激光引信优化设计提供参考.

Simulation of Underwater Laser Fuze Echo Based on Bidirectional Reflectance Distribution Function

Aiming at the necessity of torpedo laser proximity fuze detecting underwater near field target,study on Monte Carlo simulation of underwater laser fuze echo was carried out.The Monte Carlo simulation model of underwater target echo was developed based on the characteristics of underwater laser fuze detection.In order to improve the echo simulation accuracy of the underwater non-Lambertian target,The probability distribution of photon reflecting direction based on bidirectional reflectance function was derived.Then the direction of photon reflection was randomly sampled according to the probability distribution.The underwater target echo under the condition of different distances and the incident angle was simulated.The results show that target echo amplitude decreases rapidly with the increase of target distance and incident angle.The dynamic range of signal peak achieves 11.5 dB when target distance changes within 6～12 m;the dynamic range of signal peak achieves 9.2 dB when target distance is 8 m and incident angle changes within 0 ～ 45°.The experiment of underwater target laser detection was conducted in a water tank to verify the correctness of the simulation method.The experimental data have a good consistency with the simulation results.It improves the effectiveness of traditional Monte Carlo method in non-Lambertian underwater target echo simulation which provides a theoretical reference for underwater laser fuze design.