X射线脉冲星导航硬件脉冲轮廓累积研究

为了在X射线脉冲星地面实验系统仿真源模拟产生X射线的基础上,能够快速稳定地得到脉冲轮廓,采用硬件历元叠加的方法获得脉冲轮廓。研究了用硬件实现历元叠加及其数据整合的算法,该算法首先在MATLAB现场可编程逻辑阵列(FPGA)中实现,再通过MATLAB硬件描述语言(HDL)代码生成模块把算法转换成HDL,经编译后获得配置硬件的Bit文件,最终在开发板FPGA上实现数据处理的硬件模块。一段时间内的光子到达时间数据通过MATLAB算法得到的脉冲轮廓数据与通过硬件模块处理后得到的数据结果存在误差,在单个时间窗口内误差最大值为2个光子数,误差平均值占光子数统计平均值的0.084%;两组统计的脉冲轮廓数据中不同数据占总数据个数的9.481%,这样的误差不影响后端模拟导航模块的导航。利用硬件实现的历元叠加及其数据整合模块具有处理速度快、设备紧凑、功耗低的特点,为航天器利用X射线脉冲星导航提供了一种可行的硬件数据处理技术上的支持。     

Detection Performance of Soft-Limited Phase-Coded Signals

General analytic expressions are developed for the soft-limited digital pulse compressor (matched filter). This theoretical development is then used for the hardware realization of a two-channel (I,Q), 3-bit-limited digital pulse compressor with a compression ratio of 255: 1. The realized hardware uses state of the art integrated circuit devices. An experimental laboratory setup is described. This setup is used to study hard-limited versus 3-bit-limited matched-filter performance characteristics with the data in the following areas: 1) constant false alarm rate (CFAR) characteristics as a function of threshold settings and noise levels; 2) single target detection characteristics as a function of input signal-to-noise ratio (SNR); and 3) two target performance characteristics: a) the amplitude of a weaker target as a function of target ratio and target overlap; and b) the detection characteristics of a weaker target as a function of weaker target SNR, strong target SNR, and target overlap.     

基于1553B总线星时精确产生硬件秒脉冲的方法

本设计在整星不能提供硬件秒脉冲的情况下,利用单片机对1553B总线协议芯片进行配置,使其只对星时数据产生中断.该中断触发外围电路自主产生硬件秒脉冲信号,进而实现校时.由于该方法为纯硬件的触发控制环节,在不考虑卫星平台发送星时数据随机误差的情况下,其误差仅取决于硬件的延时误差,通过标定可达到与整星提供秒脉冲相同的校时精度,而大大优于不采用校时的情况.此外,该成果通过对触发电路外围进行配置,可以实现任意脉宽及方向的秒脉冲信号输出,可满足不同型号对不同类型秒脉冲信号的需求,具有很大的灵活性及广泛的适用性.     

基于DJS的射频噪声干扰信号产生方法及其特性分析

数字干扰合成(Digital Jamming Synthesis,DJS)是近年来发展起来的 1种雷达干扰技术。介绍了 2种基于 DJS的射频噪声干扰信号的产生方法;对于伪随机读取法,给出了具体实施方案、带宽调谐方法以及 1种延长干扰信号周期的解决方案;从干扰信号的带宽调谐、遮盖性能以及硬件实现系统的复杂度等方面对这 2种方法进行了比较;通过仿真验证了这 2种方法的可行性并分析了各自的性能特点。     

Onboard Attitude Error Computation for Automatic Spin Axis Control of Bhaskara

The Indian experimental remote sensing satellite, Bhaskara, uses two horizon crossing sensors mounted at 45° and 135° with respect to spin axis for onboard roll error computation and automatic control of the spin axis orientation within 3° of the orbit normal. A new method for roll error computation and control and digital hardware for the same are described. The system has flexibility to vary the threshold, to adapt to altitude variations and various mission requirements, and to work with a single horizon sensor. Flight performance of the system is satisfactory.     

用二次相关提高超声测风精度和噪声抑制性能

以超声测风为应用背景,对基于相关法的时延估计性能进行分析,指出其存在的问题。利用发射信号为已知这一先验信息,提出了二次相关估计时延的解决方法。仿真结果表明,在相同的信噪比下,与相关法相比,二次相关法能够利用先验信息,提高了时延估计的正确率,并能改善系统6dB以上的噪声抑制性能。最后,对二次相关法的运算量进行了分析,并分别以TI TMS320C5000系列DSP处理器和Ahera CycloneⅡ系列FPGA作为硬件平台,估计了该方法在这两种平台上的处理时间,得出了该方法可满足实时处理的结论。     

Near lossless data compression onboard a hyperspectral satellite

To deal with the large volume of data produced by hyperspectral sensors, the Canadian Space Agency (CSA) has developed and patented two near lossless data compression algorithms for use onboard a hyperspectral satellite: successive approximation multi-stage vector quantization (SAMVQ) and hierarchical self-organizing cluster vector quantization (HSOCVQ). This paper describes the two compression algorithms and demonstrates their near lossless feature. The compression error introduced by the two compression algorithms was compared with the intrinsic noise of the original data that is caused by the instrument noise and other noise sources such as calibration and atmospheric correction errors. The experimental results showed that the compression error was not larger than the intrinsic noise of the original data when a test data set was compressed at a compression ratio of 20:1. The overall noise in the reconstructed data that contains both the intrinsic noise and the compression error is even smaller than the intrinsic noise when the data is compressed using SAMVQ. A multi-disciplinary user acceptability study has been carried out in order to evaluate the impact of the two compression algorithms on hyperspectral data applications. This paper briefly summarizes the evaluation results of the user acceptability study. A prototype hardware compressor that implements the two compression algorithms has been built using field programmable gate arrays (FPGAs) and benchmarked. The compression ratio and fidelity achieved by the hardware compressor are similar to those obtained by software simulation     

智能抽油井示功仪

本文介绍了一种基于微控制器的抽油井示功仪的硬件结构、软件设计及其工作原理，并介绍了一种快速测试方法，即单周期测试法。     

A self-healing strategy with fault-cell reutilization of bio-inspired hardware

The self-healing strategy is a key component in designing the bio-inspired embryonics circuit with the structure of cell arrays. However, the existing self-healing strategies of embryonics circuits mainly focus on permanent faults inside the modules of cells such as the function module and the configuration register, while little attention is paid to transient faults. From the point of view of obtaining high efficiency of hardware utilization, it would be a huge waste of hardware resources by permanent elimination when a cell only suffers a transient fault which can be repaired by a configuration mechanism. A new self-healing strategy, the Fault-Cell Reutilization Self-healing Strategy(FCRSS) which presents a method for reusing transient fault cells, is proposed in this paper. The circuit structures of all the modules in the cells are described in detail. In the new strategy, two processes of elimination and reconfiguration are combined. Within the process of fault-cell elimination, cells with transient faults in the embryonics circuit array could be reused simultaneously to replace the functions of the cells on their left side in the same row. Therefore, transient fault-cells in a transparent state can be reconfigured to realize the fault-cell reutilization. Finally,a circuit simulation, resource consumption, a reliability analysis and a detailed normalization analysis are presented. The FCRSS can improve the hardware utilization rate and system reliability at the expense of a small amount of hardware resources and reconfiguration time. Following the conclusion, the method of determining the optimal self-healing strategy is presented according to the environmental conditions.     

杠杆式力标准机自动控制系统

介绍单片机用于杠杆式力标准机控制、实现检定过程自动化的设计方法，重点介绍硬件结构和软件编制。     

自适应驯服铷钟的实现

介绍了时统设备中驯服铷钟的工作原理和硬件的具体实现电路,以及单片机的嵌入式软件设计方法和数据处理方法。     

ADuC812单片机温度控制器

本文提出的单片机温度控制器，是以ADuC812芯片为核心，根据PID控制原理构成的数字控制器，文中论述了它的硬件设计方法，并给出了几组主要测试曲线，研究结果表明，该温度控制器的硬件设计简单，成本低，功耗小，体积小，控温效果好，具有实用价值。     

光纤陀螺多通道并行自动测试工艺技术

针对光纤陀螺测试过程中,测试项目多、步骤复杂、测试时间长、人为记录数据容易出错等问题,在分析测试内容的基础上提出多通道并行测试方案,设计测试工装、电缆、电路等硬件系统,开发相应的测试软件。与单只光纤陀螺测试方法相比,能够有效地减少光纤陀螺的测试时间,提高测试效率。     

An attack-immune trusted architecture for supervisory aircraft hardware

With the wide application of electronic hardware in aircraft such as air-to-ground communication, satellite communication, positioning system and so on, aircraft hardware is facing great secure pressure. Focusing on the secure problem of aircraft hardware, this paper proposes a supervisory control architecture based on secure System-on-a-Chip (SoC) system. The proposed architecture is attack-immune and trustworthy, which can support trusted escrow application and Dynamic Integrity Measurement (DIM) without interference. This architecture is characterized by a Trusted Monitoring System (TMS) hardware isolated from the Main Processor System (MPS), a secure access channel from TMS to the running memory of the MPS, and the channel is unidirectional. Based on this architecture, the DIM program running on TMS is used to measure and call the Lightweight Measurement Agent (LMA) program running on MPS. By this method, the Operating System (OS) kernel, key software and data of the MPS can be dynamically measured without disturbance, which makes it difficult for adversaries to attack through software. Besides, this architecture has been fully verified on FPGA prototype system. Compared with the existing systems, our architecture achieves higher security and is more efficient on DIM, which can fully supervise the running of application and aircraft hardware OS.     

一种基于FPGA的全帧率图像处理方法

针对图像算法在FPGA内的硬件化实现问题,提出了一种全帧率处理的思路,并提供了两种具体的可供参考的设计方法——基于像素流缓冲的卷积核处理技术和基于相邻图像帧相关性的图像参数提取技术。通过其可以方便地设计并实现大部分空间域图像处理算法及其任意组合的硬件逻辑电路,并达到与图像输入帧率相同的处理速度。以Canny算子的硬件化实现为例验证了设计理念。实验结果表明,全帧率图像方法具有可操作性强、实时性好、符合结构化模块化设计的特点,特别适合于对实时性要求高的嵌入式视觉系统。     

盘轴转子系统临界转速计算的改进传递矩阵法

在用传递矩阵法分析转子系统的临界转速时,传统的方法是忽略轮盘的厚度,将轮盘的传递矩阵作为点矩阵来处理的,这样会导致转子轴的刚度比实际模型的低,进而导致临界转速的计算结果偏低。本文将通过轮盘的传递矩阵作为场矩阵来处理,对计及轮盘厚度的传递矩阵进行了推导。分别使用传统传递矩阵法和本文提出的改进传递矩阵法对2个盘在不同位置的单盘转子模型以及一个多盘转子系统的临界转速进行了计算。对比结果表明,传统传递矩阵法的计算误差很容易就会达到一个不可忽略的水平,改进的传递矩阵法解决了这一问题。     

A method for automatic detection and characterization of plasma bubbles using GPS and BDS data

Detecting and characterizing Total Electron Content (TEC) depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble (EPB) when applying the Ground-Based Augmentation System (GBAS) at low latitudes. This paper develops a robust method to automatically identify TEC depletion and derive its parameters. The rolling barrel algorithm is used to automatically identify the TEC depletion candidate and its parameters. Then, the depletion candidates are screened by several improved techniques to distinguish actual depletions from other phenomena such as Traveling Ionospheric Disturbance (TID) or abnormal data. Next, based on the depletion signals from three triangular receivers, the method derives EPB parameters such as velocity, width and gradient. The time lag and front velocity are calculated based on cross-correlation using TEC depletions and the geometrical distribution of three triangular receivers. The width and gradient of slope are then determined by using TEC depletion from a single receiver. By comparison, both the station-pair method and proposed method depend on the assumption that the EPB morphology is frozen during the short time when the plasma bubble moves between the receivers. However, our method relaxes the restriction that the baseline length should be shorter than the width of slope required by the station-pair. This relaxation is favorable for studying small-scale slope of depletions using stations of a longer baseline. In addition, the accuracy of the width and gradient is free of impact from hardware biases and small-scale disturbance, as it is based only on the relative TEC variation. The method is demonstrated by processing Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS) data on 15 August, 2018, in a solar minimum cycle.     

Real-time ray-based channel generation and emulation for UAV communications

A real-time ray-based hardware emulator for Unmanned Aerial Vehicle (UAV) communication channels which suits for the Three-Dimensional (3D) dynamic scenarios and considers the movements of both terminals is developed in this paper. The time-variant channel parameters, i.e., ray delay, ray gain, and ray Doppler frequency are precalculated in the host by using the Ray Tracing (RT) method. Meanwhile, RT simulation dramatically increases the number of valid rays. To address the problem of resource limitation and huge computational burden in the implementation, an efficient ray coefficients generation method based on iteration is proposed and implemented. With the advantages of low cost and high flexibility, a Software Defined Radio (SDR) hardware platform is used to emulate the ray-based UAV channels by utilizing the compact architecture including the Time-Division (TD) scheme and Tapped-Delay Line (TDL) for channel convolution. Finally, hardware measurement results demonstrate that the properties of emulated channel, i.e., Power Delay Profile (PDP) and Doppler Power Spectrum Density (DPSD) consist with the simulated ones, which verifies the correctness of hardware implementation. The proposed channel emulator provides an efficient way for optimization, verification, and evaluation of UAV communication systems.     

Next generation GOES satellite power subsystem

Hughes space and communications was awarded a contract in January 1998 from NASA's Goddard Space Flight Center for the design, manufacture, integration and launch of two next generation geostationary operational environmental satellites (GOES) and options for two additional satellites. The satellites measure weather phenomena as the primary mission and X-rays and charged particles as the secondary missions. This paper describes the GOES electrical power subsystem (EPS) requirements, architecture, hardware and energy balance analysis. As of this writing, the design of the EPS has completed the critical design review phase and the hardware has entered the manufacturing phase     

Embryonic array configuration optimization method based on reliability and hardware consumption

Embryonic Array(EA) with different configuration methods will directly affect its reliability and hardware consumption. At present, EA configuration design is lack of quantitative analysis method. In order to reasonably optimize EA configuration design, an EA configuration optimization design method is proposed, which is based on the constraints of EA hardware consumption and reliability. Through the analysis of EA working process and composition, quantitative analysis of EA reliability and hardware consumption are completed. Based on the constraints of EA hardware consumption and reliability, the mathematical model of EA configuration optimization design is established, which transfers EA configuration optimization design into an integer nonlinear programming model problem. According to the difference of the fitness value of individual waiting for mutation in population, adaptive mutation operator and crossover operator are selected, and a novel Modified Adaptive Differential Evolution(MADE) algorithm is proposed,which is used to solve EA configuration optimization design problem. Simulation experiments and analysis indicate that the MADE is able to effectively improve the speed, accuracy and stability of algorithm. Moreover, the proposed EA configuration optimization design method can select the most reasonable EA configuration design, and play an important guiding role in EA optimization design.