数字化激光扫描成像引信低空海面背景目标识别方法

激光成像技术能获得精细化的空间信息，在解决超低空海洋环境背景下的目标探测与识别时具有独特的优势。文中基于海谱波动模型和激光海面回波反射特征的模拟，仿真分析了探测系统的视场角和入射角参数对海面回波特征的影响，对比分析了宽视场和窄视场在不同海况下的激光回波特征，并对比窄视场成像探测系统对目标反射和海面反射的空间分布差异。提出了一种数字化阵列激光扫描成像探测系统，该系统通过电控阵列激光分时高速工作可实现周向360°的固态扫描探测，并通过高速AD采样获取数字化的回波幅度和距离阵列。针对弹目高速交会的工作特点，提出了帧内判定，帧间累积的低空海背景目标识别方法。该方法通过直通滤波、数学形态学滤波、目标形态特征等方法能快速滤除海背景杂波，保证弹载探测识别的实时性和可靠性要求。通过不同交会条件的仿真验证，该方法对不同海况下的识别准确率的平均值为96.9%。

Target recognition method of digital laser imaging fuze in ultra-low sea background

  Objective   In order to meet the tactical requirements of modern naval warfare, air-to-air missiles should be capable of intercepting ultra-low altitude sea-sweeping flight targets such as anti-ship missiles and cruise missiles. At present, the advanced level in the world has been able to fly at a height of 3 m above the sea. In this case, the complex sea background clutter will not only affect the detection and tracking of the missile guidance system to the target, but also enter the range of the fuze at the end of the rendezvous phase, which will seriously affect the fuze work, leading to false alarm or reduced starting ability. Therefore, improving the ability of fuze to resist ultra-low altitude sea background interference has always been a research focus to expand its battlefield adaptability. At present, conventional laser fuzes use multi-quadrant zonal wavegate compression, dual-beam detection and other technologies to suppress sea clutter, but each has certain application limitations. In this paper, a low altitude sea background target recognition method based on digital laser imaging is proposed. This method is based on the difference of imaging characteristics between the sea level and the physical target in the space distribution, and uses the fine recognition ability of laser imaging to the echo characteristics of different azimuth angles, which can improve the adaptability of proximity fuze to work reliably in the ultra-low altitude sea environment.  Methods   The dynamic sea surface laser echo simulation system is established to obtain the laser scattering characteristics of sea level and target. The simulation system can set the field angle parameters of the laser imaging system, and can obtain the echo signal characteristics under different intersection conditions and different sea conditions in real time. The scattering model of sea surface panel segmentation is used to calculate the laser echo distribution characteristics under different detection field angle parameters. The simulation flow chart is shown (Fig.1). Through the statistics and analysis of the distribution characteristic data of the laser scattering echo on the sea surface, a target recognition method based on the laser imaging system for low altitude sea background is designed and verified by simulation.  Results and Discussions   In terms of target characteristic simulation, for the imaging detection system that uses spatial narrow field of view subdivision, due to the undulation of the sea surface, the sea surface echo presents discrete flicker feature in the spatial distribution (Fig.5), which is significantly different from the imaging feature of continuous solid targets (Fig.6) in the spatial distribution. In terms of target recognition method design, a circumferential 360° solid-state array laser high-speed scanning detection system is proposed, and full digital echo signal processing is realized through high-speed AD sampling. According to the characteristics of high-speed rendezvous between missile and target, a method of low altitude sea background target recognition based on intra-frame judgment and inter-frame accumulation is proposed. This method can quickly filter out the sea background clutter by means of straight-through filtering, mathematical morphology filtering, target morphology features and other methods to ensure the real-time and reliability requirements of missile-borne detection and recognition. The average recognition accuracy of this method under different sea conditions is 96.9% (Tab.2) through simulation verification of different intersection conditions.  Conclusions   In this paper, a target recognition method based on digital array laser scanning imaging is proposed. This method can realize circumferential 360° solid state scanning detection through the time-sharing and high-speed operation of the electronically controlled array laser, and digitize the echo imaging features through high-speed AD sampling. It has the characteristics of fast recognition speed and high degree of digitalization, and can meet the real-time requirements of high-speed target recognition. The digital modeling of sea surface and laser detection has been carried out, and the optical reflection characteristics of sea clutter have been simulated and analyzed. Based on the target characteristics, a low-altitude sea background target recognition method of intra-frame judgment and inter-frame accumulation has been designed. Through simulation and test verification, the average recognition accuracy of this method under different sea conditions is 96.9% (Tab.2). The relevant technologies in this paper can provide methods and ideas for laser fuze anti-low altitude sea environment interference technology.