基于嵌入式人工智能设备的流星光学监测系统

流星光学监测网是定位陨石和观测火流星的基础科研设施. 流星光学监测系统利用光学相机高速采集天空图像, 使用嵌入式系统实时处理数据, 能够快速识别流星并获取流星位置和陨石落点信息, 是构成流星监测网的关键仪器. 为提高流星光学监测系统获取信息的实时性及准确性, 提出了一种基于嵌入式人工智能设备的流星光学监测系统. 该系统由软件及硬件部分组成: 硬件部分包括观测设备(商用高空抛物摄像头)以及数据处理设备(嵌入式人工智能设备); 软件部分运行于数据处理设备内, 主要包括控制界面模块、流星监测模块、数据管理模块. 实际工作时, 摄像头采集天空视频信息, 流星监测模块从视频流中实时监测流星并存储包含流星视频的数据, 数据管理模块将流星位置信息实时传回数据中心用于预警. 观测结束后, 将原始观测数据同步至数据中心用于后续科学研究. 在整个系统中, 流星监测模块决定了整个监测系统的实时性及准确性. 该系统采用嵌入式人工智能设备与人工智能算法结合的方法构建流星监测模块. 通过使用实测数据对搭载监测模块性能进行测试, 结果表明: 流星监测模块能够达到0.28%的低误检率以及100%的召回率, 且数据处理速度达到了Mobilenetv2的8倍. 进一步将包含监测模块的整个流星光学监测系统部署于太原理工大学-张壁古堡远程天文台, 通过实测表明流星光学监测系统实用中能达到100%的召回率和较低的误检率.     

一种基于单片机的数据采集系统设计

叙述了一种基于单片机的数据采集系统硬件设计和软件编制。该系统可在工作现场自动完成排量、压力的采集、分析及数据处理工作，实现实时显示，可广泛应用于智能仪器仪表、科学研究中。     

基于GPS和RFID的城市车辆定位系统的设计

详细阐述了城市车辆导航定位技术的发展现状,深入分析了城市车辆导航定位的特点和需求,在此基础上利用嵌入式开发平台设计实现了基于GPS和RFID(无线射频识别)的车载定位系统,系统主要由GPS模块、RFID模块、GPRS(general packet radio service,通用分组无线服务)模块等部分组成。该系统通过接收GPS数据和RFID数据,依托ARM平台进行分析处理,分析处理的结果通过GPRS模块发送到监控中心以实现对车辆的监控与导航。该系统具有实时性好、可靠性高、功耗体积小等显著特点,能够满足现代城市车辆的导航与定位需要。     

移动监控终端无线传输系统的设计与实现

设计并实现了一个移动监控终端无线传输系统,该系统能够做到在不同的网络环境中实现监控终端定位信息的无线传输。结合定位终端定位信息的应用途径和当前网络环境日趋多样化的特点详细阐述了在不同网络环境中实现监控终端定位信息实时无线传输的重要性与必要性。在此基础上,较细致地说明了系统的工作原理,给出了系统结构框图,并介绍了系统各个模块的功能。实验证实,该系统可在基于IEEE802.11技术标准的WIFI无线网络和2代移动通信网络环境中实现监控终端定位信息的实时无线传输,并实现监控终端与控制中心之间简单的信息交互。     

基于无线触屏平台的阵列式望远镜控制系统

地基广角相机阵(Ground-based Wide Angle Cameras,简称GWAC)是中法合作SVOM(Space Variable Objects Monitor,空间多波段变源监视器)天文卫星的地基观测设备,Mini-GWAC是其预研和补充设备.针对Mini-GWAC望远镜阵列,介绍了一种基于无线触屏平台进行操控的阵列式望远镜控制系统的设计与实现.从控制系统原理、系统硬件结构、软件设计、实验和测试等方面展开,详细叙述了该系统的开发及实现过程.该系统以基于Win CE系统的触控一体机为上位机,无线收发模块和可编程逻辑控制器(PLC)为核心,具有低成本、数据传输可靠、操作简单等优点,并较好地实现了在Mini-GWAC阵列式望远镜上的应用.     

氢原子钟辅助电子学系统电路设计改进

氢原子钟辅助电子学系统已稳定工作多年,但是与目前的先进技术相比,原来的设计理念已显陈旧,同时暴露出外围电路庞杂、故障点比较多、问题查找困难等诸多问题;运用ARM+FPGA模式对电路进行了改进,其中运用12 bit高精度模数转换芯片实现参数采样,数字化设计改进氢原子钟智能温度控制系统,采用直接数字式频率合成器(Direct Digital Synthesizer,DDS)技术设计产生综合器频率信号,简化设计实现氢原子钟的通信功能;从测试结果来看,提高了参数的采样精度,数字化的智能温控模式实现了温度的自动化智能调整,直接式频率合成器技术简化了设计电路,基于i Coupler磁隔离技术的隔离型RS-232接口收发器设计提高了接口的稳定性;从整体设计来看,大大简化了设计电路,提高了系统性能及可靠性。     

光纤时间传递系统中时钟驯服模块的设计和实现

提出了一种基于光纤时间传递系统的时钟驯服模块设计方案。介绍了系统硬件的组成。在对信道特性和压控晶振进行理论和实验分析的基础上,设计实现了适用于光纤信道特性的卡尔曼滤波算法以及驯服流程控制程序。实验测试表明：该模块能结合恒温晶振短期稳定度好和光纤时间传递系统秒脉冲长期稳定度好的优点,时间传递的精度优于0．25ns（1σ）,输出的秒脉冲的长期稳定度优于10^-14。     

高动态GPS信号跟踪算法的Simulink实现

基于Matlab/Simul ink软件,设计实现了高动态GPS接收机的数字中频信号处理模块的仿真模型.模型可实现中频信号的跟踪和解调.给出了模拟信号源输入条件下的处理结果,结果表明模型的设计正确可行.模块可以为各种新的高动态GPS信号的跟踪算法的研究设计提供一个可视化平台.     

授时数据网络查询系统设计

为了满足用户简便地获取指定时刻和指定卫星的授时数据的需要,设计了基于互联网的授时数据查询系统,实现了系统对用户查询指令的自动回复。阐述了系统总体设计、软件的各组成模块及其实现。对系统进行了测试,结果表明系统达到了设计目的,验证了利用互联网进行授时数据查询的有效性。     

基于Altera IP核的RS译码器的设计与实现

介绍了一种基于Altera公司提供的Reed-Solomon IP（intellectual property）核来实现RS译码功能的设计方法,该方法具有开发周期短、系统成本低以及稳定可靠特点。主要分析了Altera公司提供的IP核工作原理、参数配置以及接口设计,最后通过时序仿真验证了该设计的正确性。该设计方法已经成功应用于BPL长波接收机数据解调模块中。     

Research on the Method of De-noising the Short-wave Time Signal at Low SNR

A voice enhancement algorithm based on the Empirical Mode Decomposition (EMD) and the improved spectral subtraction is proposed for the low-SNR (Signal Noise Ratio) shortwave time signal. This method is proposed to solve the problem that the shortwave time signal cannot be used for timing in complex noisy environments. The core idea of this method is to use the Hilbert-Huang Transform (HHT) algorithm to make the empirical mode decomposition on the noisy shortwave signal, and to select the intrinsic mode functions containing the shortwave signal information for the signal reconstruction by through the maximum correlation. Then, to make the spectral subtraction on the reconstructed signal to achieve the purpose of noise reduction. The experimental result shows that this method has a better noise reduction than the traditional methods.     

Numerical study of a 20W class QCW pulsed sodium guide star laser's performances at five sites in China

In the past few years,Chinese astronomical community is actively testing astronomical sites for several new optical/infrared ground-based telescopes.These site testing campaigns conducted were mainly focused on fundamental performances of the sites,such as cloud coverage,seeing,temperature,etc.With increasing interests in sodium laser guide star adaptive optics for these new telescopes in the Chinese astronomical community,it is interesting to investigate the performance of the laser guide star at these sites,especially considering that the sodium laser guide star's on-sky performance is significantly influenced by sites' local performances,such as geomagnetic field,sodium layer dynamics,density of air molecule,etc.In this paper,we studied sodium laser guide star's performance of a 20 W class Quasi Continuous Wave(QCW) pulsed laser developed by TIPC with numerical simulation for five selected sites in China.     

New challenges for adaptive optics: extremely large telescopes

The performance of an adaptive optics (AO) system on a 100-m diameter ground-based telescope working in the visible range of the spectrum is computed using an analytical approach. The target Strehl ratio of 60 per cent is achieved at 0.5 μm with a limiting magnitude of the AO guide source near R   magnitude~10, at the cost of an extremely low sky coverage. To alleviate this problem, the concept of tomographic wavefront sensing in a wider field of view using either natural guide stars (NGS) or laser guide stars (LGS) is investigated. These methods use three or four reference sources and up to three deformable mirrors, which increase up to 8-fold the corrected field size (up to 60 arcsec at 0.5 μm). Operation with multiple NGS is limited to the infrared (in the J band this approach yields a sky coverage of 50 per cent with a Strehl ratio of 0.2). The option of open-loop wavefront correction in the visible using several bright NGS is discussed. The LGS approach involves the use of a faint ( R ~22) NGS for low-order correction, which results in a sky coverage of 40 per cent at the Galactic poles in the visible.     

Prospects for the GLAS Rayleigh laser beacon on the 4.2-m WHT

The scientific exploitation of adaptive optics (AO) with natural guide stars is severely constrained by the limited presence of bright guide stars for wavefront sensing. Use of a laser beam as an alternative means to provide a source for wavefront sensing has the potential of drastically improving the sky coverage for AO. For this reason at the 4.2-m William Herschel Telescope a project was started to develop a Rayleigh laser beacon to work together with the existing NAOMI adaptive optics instrumentation and the OASIS integral field spectrograph. This paper presents the rationale for this development, highlights some of the technical aspects, and gives some expected performance measures.     

用于自适应光学系统的激光引导星

自适应光学系统应用于天文观测时应满足一些技术要求,其中的关键技术之一是自适应光学系统为了对畸变的光波进行采样,需要在其很小的等晕角内有足够的信标强度。激光引导星,即人造信标,就是解决这种问题的方法之一。特别是在观测天文暗目标时,其自身的光强度不能为有探测提供信息,激光引导星就蛤得非常重要。根据国际上的最新进展对激光引导星技术给予了介绍。重点介绍了激光引导星的局限性,对近几年提出的对激光引导星可能的     

Improving the seeing with wide-field adaptive optics in the near-infrared

In this paper, we present simulation results of a ground-layer correction adaptive optics system (GLAO), based on four laser guide stars and a single deformable mirror. The goal is to achieve a seeing improvement over an 8-arcmin field of view, in the near-infrared (from 1.06 to 2.2 μm). We show results on the scaling of this system (number of subapertures, frame rates), and the required number of tip-tilt stars. We investigate the use for GLAO of both sodium and Rayleigh guide stars. We also show that if the lasers can be repositioned, the performance of the adaptive optics can be tailored to the astronomical observations.     

A Road Map for the Generation of a Near-Infrared Guide Star Catalog for Thirty Meter Telescope Observations

The near-infrared instruments in the upcoming Thirty Meter Telescope (TMT) will be assisted by a multi conjugate Adaptive Optics (AO) system. For the efficient operation of the AO system, during observations, a near-infrared guide star catalog which goes as faint as 22 mag in J_Vega band is essential and such a catalog does not exist. A methodology, based on stellar atmospheric models, to compute the expected near-infrared magnitudes of stellar sources from their optical magnitudes is developed. The method is applied and validated in JHKs bands for a magnitude range of J_Vega 16–22 mag. The methodology is also applied and validated using the reference catalog of PAN STARRS. We verified that the properties of the final PAN STARRS optical catalog will satisfy the requirements of TMT IRGSC and will be one of the potential sources for the generation of the final catalog. In a broader context, this methodology is applicable for the generation of a guide star catalog for any existing/upcoming near-infrared telescopes.     

Multi-aperture seeing profiler with multiple guide stars

The daytime atmospheric turbulence profile is crucial for the design of both optical systems and the control algorithm of a solar Multi-Conjugate Adaptive Optics(MCAO) system. The Multi-Aperture Seeing Profiler(MASP) is a portable instrument which can measure the daytime turbulence profile up to~30 km. It consists of two portable small telescopes that can deliver performance similar to a SolarDifferential Image Motion Monitor +(S-DIMM+) on a 1.0 m solar telescope. In the original design of MASP, only two guide stars are used to retrieve the turbulence profile. In this paper, we studied the usage of multiple guide stars in MASP using numerical simulation, and found that there are three main advantages.Firstly, the precision of the turbulence profile can be increased, especially at a height of about 15 km, which is important for characterizing turbulence at the tropopause. Secondly, the equivalent diameter of MASP can be increased up to 30%, which will reduce the cost and weight of the instruments. Thirdly, the vertical resolution of the turbulence profile near the ground increases with the help of multiple guide stars.     

Automatic guide for the Raduga astronomical spectrograph

An automatic mirror guide has been designed and made for the Raduga fiber-optic echelle spectrograph. The new device was built into one of the parts of the spectrograph and allows the work of observers to be facilitated significantly. The automatic guide efficiently removes stellar image oscillations at frequencies of 0–2 Hz, which compensates almost completely for errors in setting the polar axis of a telescope and in its clockwork drive. The guide can be used on any telescope with a focal length of more than 5 m and has operated on two different telescopes. Over two observing seasons, several hundred stellar spectra were taken with the Raduga spectrograph using the automatic guide.