本文采用电磁波雷达作为测量设备,解决了现有船舶水尺计重过程中的难题,并结合激光测距仪准确定位,计算出实际吃水深度。同时,利用远距离无线电(Long Range Radio,LoRa)无线通讯技术进行信号传输,利用实验室虚拟仪器工程平台(Laboratory...本文采用电磁波雷达作为测量设备,解决了现有船舶水尺计重过程中的难题,并结合激光测距仪准确定位,计算出实际吃水深度。同时,利用远距离无线电(Long Range Radio,LoRa)无线通讯技术进行信号传输,利用实验室虚拟仪器工程平台(Laboratory Virtual Instrument Engineering Workbench,LabVIEW)虚拟仪器技术进行设备控制,实现长时间、多点同时测量,将得到的数字信号用预设的算法自动筛选出数据,并形成直观图像供检验人员筛选、判断。与传统方法比较,前后尺总体差异小于0.1%,符合计重标准要求,提高了测量准确率,具有较大的推广前景。展开更多
Free-space laser communication is characterized by high communication speed, strong anti-jamming ability, high confidentiality, and flexible configuration. In this paper, a pointing, acquisition, and tracking (PAT) sy...Free-space laser communication is characterized by high communication speed, strong anti-jamming ability, high confidentiality, and flexible configuration. In this paper, a pointing, acquisition, and tracking (PAT) system based on a two-stage (i.e., coarse and fine) composite tracking mechanism is proposed to solve the optical axis alignment problem, which is common in free-space laser communications. The acquisition probability of the PAT system is ensured by designing two tracking modules, a coarse tracking module which combines passive damping with active suppression and a fine tracking module based on an electromagnetic galvanometer. Both modules are combined by using a dynamic scanning mechanism based on the gyroscope signal. Finally, a free-space laser communication test with a long range and a high speed is conducted by two fixed-wing Y12 aircrafts equipped with the proposed PAT system. Experimental results show that the coarse tracking precision of the airborne PAT system is 10 μrad (1σ), and the fine tracking precision is 10μrad (1σ) during flights which are much improved as compared with the indoor tests. This indicates that the system can achieve a high precision for PAT during high-speed and long-range laser communications in the free-space. This also verifies the tracking capability and the environmental adaptability of the proposed laser communication PAT system.展开更多
基金the National Natural Science Foundation of China (Grant No. 51505087).
文摘Free-space laser communication is characterized by high communication speed, strong anti-jamming ability, high confidentiality, and flexible configuration. In this paper, a pointing, acquisition, and tracking (PAT) system based on a two-stage (i.e., coarse and fine) composite tracking mechanism is proposed to solve the optical axis alignment problem, which is common in free-space laser communications. The acquisition probability of the PAT system is ensured by designing two tracking modules, a coarse tracking module which combines passive damping with active suppression and a fine tracking module based on an electromagnetic galvanometer. Both modules are combined by using a dynamic scanning mechanism based on the gyroscope signal. Finally, a free-space laser communication test with a long range and a high speed is conducted by two fixed-wing Y12 aircrafts equipped with the proposed PAT system. Experimental results show that the coarse tracking precision of the airborne PAT system is 10 μrad (1σ), and the fine tracking precision is 10μrad (1σ) during flights which are much improved as compared with the indoor tests. This indicates that the system can achieve a high precision for PAT during high-speed and long-range laser communications in the free-space. This also verifies the tracking capability and the environmental adaptability of the proposed laser communication PAT system.
