VXI or PXI test system improvement using DSP

The results of a study into the use of distributed digital signal processing (DSP) at the instrument level in a VXI and PXI based test system and the effects on test time. One of the limiting factors in testing mixed signal or analog devices using standard bus based instruments is the transfer speed from the instrument to the controlling computer of large amounts of waveform data. This is important as these types of tests use non-deterministic, quantized signals that must be mathematically processed to extract test information. This processing can either be done at the instrument or at the central controller. If the processing is done at the instrument then only the results are transferred to the controller. If the controller does the processing then the raw data must be transferred to and from the instrument. Using two instruments, one in VXI and one in PXI, this paper measures the effects of typical tests contesting the measurements as done in the central processor as opposed to a distributed DSP processor in each instrument For each acquisition instrument, tests were implemented by capturing the data and moving it to the controlling computer where it was processed to extract test results, or by using the instruments on-board DSP so only the final test results were set to the controlling computer. The study results show that a significant improvement in test time can be made by selecting "smart" instruments for the test system when using PXI or VXI based instruments.     

Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Monolithic Interferometer Design and Test

The design and laboratory tests of the interferometers for the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument which measures thermospheric wind and temperature for the NASA-sponsored Ionospheric Connection (ICON) Explorer mission are described. The monolithic interferometers use the Doppler Asymmetric Spatial Heterodyne (DASH) Spectroscopy technique for wind measurements and a multi-element photometer approach to measure thermospheric temperatures. The DASH technique and overall optical design of the MIGHTI instrument are described in an overview followed by details on the design, element fabrication, assembly, laboratory tests and thermal control of the interferometers that are the heart of MIGHTI.     

MICROSCOPE On-ground and In-orbit Calibration

The MICROSCOPE mission, to be launched in 2011, will perform the test of the universality of free fall (Equivalence Principle) to an accuracy of 10^?15. The payload consists of two sensors, each controlling the free fall of a pair of test masses: the first for the test of the Equivalence Principle (titanium/platinum), the second for performance verification (platinum/platinum). The capability to detect a faint violation signal of the EP test is conditioned upon the rejection of disturbances arising from the coupling and misalignments of the instrument vectorial outputs. Therefore the performance of the mission depends on the success of the series of calibration operations which are planned during the satellite life in orbit. These operations involve forced motion of the masses with respect to the satellite. Specific data processing tools and simulations are integral parts of the calibration and performance enhancement process, as are the tests operated on ground at the ZARM drop tower. The presentation will focus on the current status of the MICROSCOPE payload, the rationale for the in-orbit calibrations, the data processing operations and the tests performed at the ZARM drop tower.     

采用286微机游戏口控制的肾功能仪

本文介绍了核医学类典型仪器肾功能仪的基本原理，提出了将老肾功能仪改造成智能化肾功能仪的一种方法并实际实现了该方法。通过改进微机游戏口的设计和结合高级语言编程对仪器进行简便改造和控制，给人们提供了微机接口应用的一种较新颖和较简单的方法，为改造老仪器老设备也提供了参考实例。     

超燃冲压发动机典型部件热防护

通过在电弧加热器上的试验考核,对进气道唇口前缘、注油支杆等发动机典型被动热防护部件的材料选择和热结构设计进行了研究.发展了主动冷却燃烧室热结构计算评估方法,将经过试验验证的热分析程序应用于燃烧室主动冷却结构的材料配置研究.材料C1和C2的进气道唇口前缘经过60s试验后情况良好;材料Z1的注油支杆经历50s试验后情况良好;将主动冷却燃烧室热分析计算程序应用于冷却面板试验,温度测量值与计算值最大相差55K,表明计算与试验符合较好,计算程序可为主动冷却燃烧室结构材料配置的设计研究提供可信的参考数据.研究所获得的经验和技术可应用于全流道超燃冲压发动机的设计与验证.      

Radar: The Cassini Titan Radar Mapper

The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will provide information on relative elevations in selected areas. Surfaces of the Saturn’s icy satellites will be explored utilizing the RADAR radiometer and scatterometer modes. Saturn’s atmosphere and rings will be probed in the radiometer mode only. The instrument is a joint development by JPL/NASA and ASI. The RADAR design features significant autonomy and data compression capabilities. It is expected that the instrument will detect surfaces with backscatter coefficient as low as −40 dB.RADAR Team LeaderThis revised version was published online in July 2005 with a corrected cover date.     

用AM300型函数信号发生器建立相位测量标准装置

提出了一种建立相位测量标准装置的方法。该标准装置以AM300型函数信号发生器为主标准器,相位计、示波器、失真度测量仪、数字电压表为配套设备。对AM300型函数信号发生器的量值指标进行了测试和实验,包括：相位增量误差测试、相位绝对零度误差测试、60°幅相误差测试、测量的重复性实验和长期稳定性实验。结果表明：该标准装置测试结果准确,性能稳定可靠,具有造价低、实用性强的特点。     

The GGS/POLAR magnetic fields investigation

The magnetometer on the POLAR Spacecraft is a high precision instrument designed to measure the magnetic fields at both high and low altitudes in the polar magnetosphere in 3 ranges of 700, 5700, and 47000 nT. This instrument will be used to investigate the behavior of fieldaligned current systems and the role they play in the acceleration of particles, and it will be used to study the dynamic fields in the polar cusp, magnetosphere, and magnetosheath. It will measure the coupling between the shocked magnetosheath plasma and the near polar cusp magnetosphere where much of the solar wind magnetosphere coupling is thought to take place. Moreover, it will provide measurements critical to the interpretation of data from other instruments. The instrument design has been influenced by the needs of the other investigations for immediately useable magnetic field data and high rate (100+vectors s^–1) data distributed on the spacecraft. Data to the ground includes measurements at 10 vectors per second over the entire orbit plus snapshots of 100 vectors per second data. The design provides a fully redundant instrument with enhanced measurement capabilities that can be used when available spacecraft power permits.     

The comptel experiment on the NASA Gamma-Ray Observatory

The imaging Compton telescope COMPTEL will be flown on the NASA Gamma-Ray Observatory at the beginning of the next decade. The instrument with its wide field of view and improved angular resolution will provide the first sky survey at MeV energies, as well as deep studies of galactic and extragalactic gamma-ray point sources and diffuse emission. The hardware preparations are close to completion, with calibrations to be done in 1987 prior to integration of the instrument onto the observatory carrying 3 other gamma ray detectors.     

Specifying an IVI class for digital test instrumentation

This paper presents an overview of work being done by Teradyne in conjunction with the IVI Foundation to specify an IVI class for digital instrumentation. The Interchangeable Virtual Instruments (IVI) Foundation was formed in August 1997 to define standard specifications for programming common test instrument capabilities. The paper will present the major architectural aspects of digital test instrumentation and how those features can be grouped into classes for the purpose of writing an instrument independent driver. Topics discussed will include derivation of capability classes, class extensions, simulation, and range checking. Examples of how the IVI digital class would apply to the Teradyne M9-Series Digital Test Instrument will be included. Conclusions will summarize the unique attributes of digital test instrumentation, the benefits which can be achieved through standardization, and the tradeoffs associated with utilizing class extensions     

The Galileo Heavy element monitor

The Heavy Ion Counter on the Galileo spacecraft will monitor energetic heavy nuclei of the elements from C to Ni, with energies from 6 to 200 MeV nucl^-1. The instrument will provide measurements of trapped heavy ions in the Jovian magnetosphere, including those high-energy heavy ions with the potential for affecting the operation of the spacecraft electronic circuitry. We describe the instrument, which is a modified version of the Voyager CRS instrument.     

The Noise Model of the SEIS Seismometer of the InSight Mission to Mars

The SEIS (Seismic Experiment for Interior Structures) instrument on board the InSight mission to Mars is the critical instrument for determining the interior structure of Mars, the current level of tectonic activity and the meteorite flux. Meeting the performance requirements of the SEIS instrument is vital to successfully achieve these mission objectives. The InSight noise model is a key tool for the InSight mission and SEIS instrument requirement setup. It will also be used for future operation planning. This paper presents the analyses made to build a model of the Martian seismic noise as measured by the SEIS seismometer, around the seismic bandwidth of the instrument (from 0.01 Hz to 1 Hz). It includes the instrument self-noise, but also the environment parameters that impact the measurements. We present the general approach for the model determination, the environment assumptions, and we analyze the major and minor contributors to the noise model.     

MESSENGER and the Chemistry of Mercury’s Surface

The instrument suite on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft is well suited to address several of Mercury’s outstanding geochemical problems. A combination of data from the Gamma-Ray and Neutron Spectrometer (GRNS) and X-Ray Spectrometer (XRS) instruments will yield the surface abundances of both volatile (K) and refractory (Al, Ca, and Th) elements, which will test the three competing hypotheses for the origin of Mercury’s high bulk metal fraction: aerodynamic drag in the early solar nebula, preferential vaporization of silicates, or giant impact. These same elements, with the addition of Mg, Si, and Fe, will put significant constraints on geochemical processes that have formed the crust and produced any later volcanism. The Neutron Spectrometer sensor on the GRNS instrument will yield estimates of the amount of H in surface materials and may ascertain if the permanently shadowed polar craters have a significant excess of H due to water ice. A comparison of the FeO content of olivine and pyroxene determined by the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) instrument with the total Fe determined through both GRNS and XRS will permit an estimate of the amount of Fe present in other forms, including metal and sulfides.     

SOHO operations and ground system

SOHO is a joint ESA/NASA mission to study the sun from its interior to, and including, the solar wind in interplanetary space. It is currently scheduled for launch in 1995. After launch SOHO with be operated from the Experiment Operations Facility (EOF) at Goddard Space Flight Center (GSFC). The EOF will consist of facilities for instrument commanding, data reception, data reduction and data analysis. In this paper the operations concepts including instrument ground commanding from the EOF and communications capabilities between the EOF and ground observatories and the public networks in general will be described.     

飞机虚拟仪表建模仿真关键技术研究

将介绍虚拟仪表设计软件的设计思路和功能作用。首先介绍了现有的虚拟仪表设计方法，分析其优缺点；之后介绍自主研发的虚拟仪表设计软件的特点，分析设计思路，分解介绍各模块的功能，给出仿真案例及最后的仿真效果。该虚拟仪表设计软件完全自主研发，具有易用性、可迅速建模、容易更改，模块化，通用性等特点。     

驾驶舱仿真仪表显示系统设计

以某型民用飞机为背景,阐述了飞控系统功能验证的重要性以及驾驶员在环试验对飞控系统功能的验证作用。在此基础上,介绍并设计了作为驾驶员在环试验重要评定依据的驾驶舱仿真仪表显示系统。此系统利用VC＋＋6.0和OpenGL编程工具的核心优势,同时采用VMIC实时网通讯保证了仿真仪表显示的实时性。并通过驾驶员在环试验,验证了驾驶舱仿真仪表显示系统的实时性和可靠性,能够满足飞机地面模拟试验的需求。     

The Lightning And Radio Emission Detector (LRD) instrument

The Lightning and Radio Emission Detector (LRD) instrument will be carried by the Galileo Probe into Jupiter's atmosphere. The LRD will verify the existence of lightning in the atmosphere and will determine the details of many of its basic characteristics. The instrument, operated in its magnetospheric mode at distances of about 5, 4, 3, and 2 planetary radii from Jupiter's center, will also measure the radio frequency (RF) noise spectrum in Jupiter's magnetosphere. The LRD instrument is composed of a ferritecore radio frequency antenna ( 100 Hz to 100 kHz) and two photodiodes mounted behind individual fisheye lenses. The output of the RF antenna is analyzed both separately and in coincidence with the optical signals from the photodiodes. The RF antenna provides data both in the frequency domain (with three narrow-band channels, primarily for deducing the physical properties of distant lightning) and in the time domain with a priority scheme (primarily for determining from individual RF waveforms the physical properties of closeby-lightning).     

Galileo Probe Mass Spectrometer experiment

The Galileo Probe Mass Spectrometer (GPMS) is a Probe instrument designed to measure the chemical and isotopic composition including vertical variations of the constituents in the atmosphere of Jupiter. The measurement will be performed by in situ sampling of the ambient atmosphere in the pressure range from approximately 150 mbar to 20 bar. In addition batch sampling will be performed for noble gas composition measurement and isotopic ratio determination and for sensitivity enhancement of non-reactive trace gases.The instrument consists of a gas sampling system which is connected to a quadrupole mass analyzer for molecular weight analysis. In addition two sample enrichment cells and one noble gas analysis cell are part of the sampling system. The mass range of the quadrupole analyzer is from 2 amu to 150 amu. The maximum dynamic range is 10⁸. The detector threshold ranges from 10 ppmv for H₂O to 1 ppbv for Kr and Xe. It is dependent on instrument background and ambient gas composition because of spectral interference. The threshold values are lowered through sample enrichment by a factor of 100 to 500 for stable hydrocarbons and by a factor of 10 for noble gases. The gas sampling system and the mass analyzer are sealed and evacuated until the measurement sequence is initiated after the Probe enters into the atmosphere of Jupiter. The instrument weighs 13.2 kg and the average power consumption is 13 W.The instrument follows a sampling sequence of 8192 steps and a sampling rate of two steps per second. The measurement period lasts appropriately 60 min through the nominal pressure and altitude range.