实时辨识气动特性的一种动力学模型

本文提出一种6自由度动力学模型,结合广义卡尔曼滤波(EKF)算法,对实时辨识再入体气动特性的问题进行了研究,作了广泛的数值仿真。 本文的动力学模型与某一常规模型进行了详细比较:(1)本模型免去了常规模型中不太现实的测高假设和大气模型假设。(2)本模型可精确估计气动系数比,其中包括重要的静稳定度。此外,文章还对收敛时间、模型误差等进行了分析对比。 结果表明,与常规模型比较,本模型具有一定的优越性。     

分布式遥测遥控数据处理平台构想

根据机载导弹技术的未来发展规划以及国际遥测遥控数据处理技术的发展趋势 ,提出分布式遥测遥控数据处理平台。从视频处理角度 ,对平台开发的必要性、可行性、功能设计、实施规划等方面进行阐述     

实时遥测数据融合机制研究

在分布式遥测系统中,实时遥测数据融合软件可以任意驻留在采集服务器或者任一客户端上,也可以单独运行在一台数据融合服务器上,完成设备数据管理、实时数据融合、融合效果评估输出等功能。采用多数据流智能选择实时融合模式并联方式工作,将大大提高系统输出正确数据的可靠性,同时确保指挥大厅数据显示的准确性。     

无人机机载合成孔径雷达的高速数据传输

无人机机载合成孔径雷达 (SAR)的高速数据传输问题是长期以来制约 SAR载荷应用的重要问题。文中通过对 SAR原始数据、SAR成像、SAR图像数据以及传输系统的研究 ,提出将 SAR成像过程分为两个阶段 ,在机上进行预滤波 ,在地面进行距离向压缩、方位向压缩等成像过程 ,实时传输经过预滤波和压缩后的数据。该方案在保证 SAR方位向和距离向分辨率及测绘带带宽的前提下 ,能够有效降低下传数据率 (具体值取决于预滤波率 ) ,同时不增加无人机的载荷 ,是一种可行的实时高速数据传输方案     

氢激射器频率稳定度的微机实时测试系统

对于一个实用的氢频标来说,其频率稳定度的测试,特别是实时稳定度测试,腔体调谐与线Q值的测试都是必不可少的。以前。我们都是手工来完成这些工作的,既烦琐又不准确,且在实用过程中不能给出实时的频率稳定度值,1986年后,我们用Apple(?)微机作为主体部分建立了频率稳定度实时测试系统,它不仅给出实时的稳定度,且同时进行腔体调谐与线Q测试,既方便又使测试精度大大提高。本文将描述这套测试系统,给出氢钟经改进后由这套系统测得的最新结果。     

Response of a pentagonal PZT element as a component of a 4π-real-time detector

The detector characteristics of a pentagonal element were studied by colliding it with hypervelocity micro-particles. A charge-sensitive amplifier was developed for the element of its capacitance ∼10 nF. The output amplitudes were expressed as a linear function of the momentum at collision. Empirical formulas obtained from on-ground experiments could be used for the calibration of the detector. The pentagonal element was potential to measure the momentum during collision from the output amplitude. A set of electrodes on the surface was used to confirm the measurement of the coordinates at collision. A possible application of this pentagonal element on a real-time dust detector was discussed.     

The GFZ real-time GNSS precise positioning service system and its adaption for COMPASS

Motivated by the IGS real-time Pilot Project, GFZ has been developing its own real-time precise positioning service for various applications. An operational system at GFZ is now broadcasting real-time orbits, clocks, global ionospheric model, uncalibrated phase delays and regional atmospheric corrections for standard PPP, PPP with ambiguity fixing, single-frequency PPP and regional augmented PPP. To avoid developing various algorithms for different applications, we proposed a uniform algorithm and implemented it into our real-time software. In the new processing scheme, we employed un-differenced raw observations with atmospheric delays as parameters, which are properly constrained by real-time derived global ionospheric model or regional atmospheric corrections and by the empirical characteristics of the atmospheric delay variation in time and space. The positioning performance in terms of convergence time and ambiguity fixing depends mainly on the quality of the received atmospheric information and the spatial and temporal constraints. The un-differenced raw observation model can not only integrate PPP and NRTK into a seamless positioning service, but also syncretize these two techniques into a unique model and algorithm. Furthermore, it is suitable for both dual-frequency and sing-frequency receivers. Based on the real-time data streams from IGS, EUREF and SAPOS reference networks, we can provide services of global precise point positioning (PPP) with 5–10 cm accuracy, PPP with ambiguity-fixing of 2–5 cm accuracy, PPP using single-frequency receiver with accuracy of better than 50 cm and PPP with regional augmentation for instantaneous ambiguity resolution of 1–3 cm accuracy. We adapted the system for current COMPASS to provide PPP service. COMPASS observations from a regional network of nine stations are used for precise orbit determination and clock estimation in simulated real-time mode, the orbit and clock products are applied for real-time precise point positioning. The simulated real-time PPP service confirms that real-time positioning services of accuracy at dm-level and even cm-level is achievable with COMPASS only.     

End-to-end validation process for the INTA-Nanosat-1B Attitude Control System

This paper describes the end-to-end validation process for the Attitude Control Subsystem (ACS) of the satellite INTA-NanoSat-1B (NS-1B). This satellite was launched on July 2009 and it has been fully operative since then. The development of its ACS modules required an exhaustive integration and a system-level validation program. Some of the tests were centred on the validation of the drivers of sensors and actuators and were carried out over the flying model of the satellite. Others, more complex, constituted end-to-end tests where the concurrency of modules, the real-time control requirements and even the well-formedness of the telemetry data were verified. This work presents an incremental and highly automatised way for performing the ACS validation program based on two development suites and an end-to-end validation environment. The validation environment combines a Flat Satellite (FlatSat) configuration and a real-time emulator working in closed-loop. The FlatSat is built using the NS-1B Qualification Model (QM) hardware and it can run a complete version of the on-board software with the ACS modules fully integrated. The real-time emulator, running on an industrial PC, samples the actuation signals and emulates the sensors signals to close the control loop with the FlatSat. This validation environment constitutes a low-cost alternative to the classical three axes tilt table, with the advantage of being easily configured for working under specific orbit conditions, in accordance with any of the selected tests. The approach has been successfully applied to the NS-1B in order to verify different ACS modes under multiple orbit scenarios, providing an exhaustive coverage and reducing the risk of eventual errors during the satellite's lifetime. The strategy was applied also during the validation of the maintenance and reconfiguration procedures required once the satellite was launched. This paper describes in detail the complete ACS validation process that was performed and it shows the most relevant errors detected and fixed during testing. Finally it summarises some of the most significant conclusions.     

A heuristic design method for attitude stabilization of magnetic actuated satellites

In this paper a heuristic design strategy for stabilizing the satellite attitude has been proposed. It is assumed that the satellite is actuated by a set of mutually perpendicular magnetic coils. Using well-known Lyapunov direct stability method it is shown that the proposed controller causes to a global asymptotic stable system for all near polar orbits. The design procedure is based on analyzing of the conceptual effects of magnetic coils on the satellite attitude motion. Considering these effects lead to some intuitive results which determine the global stabilizing control law. The performance and robustness of the designed controller against actuators saturation and quantization error have been verified using a real-time-hardware–software in-loop (RTHSIL) simulation results. These results show that the global stability can be achieved although some disturbances and restrictions exist. This stabilizing controller can be simply combined with a linear explicit model predictive controller (EMPC) to achieve a full three-axis control law.     

基于CAN总线的虚拟化以太网接口设计和实现

针对卫星载荷间基于控制器局域网（CAN）总线的IP通信,提出了一种CAN接口虚拟化机制,称为IPoverCAN。通过IP地址和CAN地址映射、IP报文分片/重组和多路缓冲队列管理等机制,将CAN接口抽象为虚拟的标准以太网接口。试验结果表明,IPoverCAN机制实现了CAN数据帧和IP报文之间的实时高效转换,可用于卫星载荷间通信等对设备质量和体积敏感的领域。