Field test results prove GPS performance and utility

Statistical and operational results of extensive government field-testing of the Rockwell-Collins Global Positioning System (GPS) units are summarized. The equipment has exhibited better than 16-m spherical-error probable-position accuracy in over 6300 hours of testing conducted during the past two years. One-channel, two-channel, and five-channel receivers were subjected to thorough evaluation. Their respective signal-processing and data-processing architectures are described. Data highlighting dynamic position accuracy, static position accuracy, acquisition times, and field reliability are presented. GPS equipment integration and operation with nine different host vehicles is described. The results of mission scenarios, such as area navigation, rendezvous, and weapon delivery, are presented     

Analysis of APIAN high speed isolated test results - acoustics and aerodynamics

The APIAN programme (Advanced Propulsion Integration Aerodynamics and Noise) launched in 1996 under the coordination of AM Airbus follows GEMINI (1990–1993), and GEMINI II and SNAAP (1993–1996) and the huge advances achieved in 10 years show the large effort allowed by the European scientific community since the end of the 80s to understand propeller physics. This paper details the important experimental achievements of the isolated propeller test in the ONERA S1MA transonic facility; preliminary results of the installed S1MA test in ONERA S1MA are also shortly discussed.     

NETEX UWB test results

The goal of the Defense Advanced Research Projects Agency's (DARPA) Networking in Extreme Environments (NETEX) program is to create a wireless networking technology for the military user that enables robust connectivity in harsh environments and support its integration into new and emerging sensor and communication systems. Phase 1, resulted in a thorough understanding of the effects of ultra wide band (UWB) system operation on existing military spectrum users based on modeling, simulation, and measurements. In order to accomplish this task, the DARPA Advanced Technology Office (ATO) procured a set of UWB emitters and broadband antennas to use as interference sources and contracted with the Naval Air Warfare Center Aircraft Division (NAWC AD) Electromagnetic Environmental Effects (E/sup 3/) Division to provide candidate victim systems from the existing (legacy) US naval aircraft and shipboard inventory for testing. Testing was conducted on seventeen legacy systems during October 2002 through March 2003. The purpose of this paper is to provide a brief overview of the results of these tests. This paper will provide a brief discussion of the UWB emissions as described by the US Federal Communications Commission (FCC) and describe the generic UWB emitter used for these tests. It will then provide a discussion of the results as they apply to the purpose of the NETEX program.     

模型大迎角高速动态特性与数据精度分析

为满足新一代高机动飞机气动性能评估、控制系统精确设计与高机动作战指标实现的需求,模型高速风洞大迎角俯仰动态特性探索及其试验数据精度的确定势在必行,且具有十分重要的工程意义。选取70°三角翼模型、SDM和Su-27飞机模型,在FL-24风洞的大振幅俯仰动态试验技术平台上对动态气动特性与试验数据精度进行了研究,获取了70°三角翼模型、SDM和Su-27飞机模型动态气动特性与重复性试验结果。研究结果表明：试验条件下,3种模型的动态数据精度较高,基本达到了高速风洞大迎角常规测力试验数据的精度水平。     

航空发动机离心通风器性能试验

为获取某型发动机离心通风器性能,通过试验模拟通风器的油雾工作环境,综合运用测质量法与光学测量方法,获取分离效率、粒径分布与压降数据.试验结果显示,分离效率随转速增加呈现先线性上升后平缓的规律.转速从静态增加到1000 r/min,分离效率增加10％,油雾平均直径从1.8μm降低至1.3μm,粒径2.0～3.0μm基本被...     

基于地面试车数据的高涵道比涡扇发动机飞行性能预估方法

为了预估高涵道比涡扇发动机飞行性能,使用GasTurb 11软件的试车数据分析功能计算出了某高涵道比涡扇发动机地面试车点与设计点各部件效率和流路损失的偏差.通过非设计点敏感性分析确定设计点与地面试车点的效率与损失偏差的相关性,最后预估得到高涵道比涡扇发动机的飞行性能.对某高涵道比涡扇发动机飞行性能预估研究表明:该方法切实可行,其中地面试车数据分析、地面和设计点偏差关系图、以及非设计敏感性分析是预估高涵道比涡扇发动机飞行性能的3个关键环节。      

仿真结果检验和状态分析方法

提出了一种仿真结果检验和状态分析方法,不仅可以有效地判断仿真结果正确与否,而且当仿真结果不正确时,可以进一步对仿真结果进行状态分析,确定哪些状态的仿真结果正确,哪些状态的仿真结果错误,从而指导仿真软件系统的编制和修改.此外,还给出了仿真结果检验表和状态分析表,便于工程应用.      

模拟板吹风试验结果与数值模拟结果关联规律

采用CFD方法对恶劣图谱模拟板进行模拟,通过对模拟结果和试验结果进行对比分析,总结出CFD模拟结果与吹风试验结果的关联规律。结果表明:畸变指数关联方法,适用于任何堵塞比的模拟板,可以保证周向畸变指数一致,但不能保证低压区范围相近和总压分布相似;距离关联方法既可保证周向畸变指数一致,又能保证低压区范围和总压分布相似,但只适用于堵塞比较小的情况。     

确定性仿真结果检验与状态分析方法

为判断多状态的仿真结果正确与否,建立了变异系数相等情况下的确定性仿真结果检验方法.同时,在变异系数相等或方差相等的情况下,分别建立了一种确定性仿真结果状态分析方法,可对仿真结果的各个状态逐一进行分析,以确定哪些状态已被正确仿真,哪些状态尚未被正确模拟,从而指导仿真软件的编制.     

确定性仿真结果检验和因子分析方法

提出一种确定性仿真结果(不考虑随机因素影响的仿真结果)检验方法, 能够对仿真结果与试验结果之间的误差进行分析, 确定该误差是由于仿真不正确引起的系统误差, 还是由于试验结果的分散性引起的偶然误差, 进而判断仿真结果正确与否.同时建立一种确定性仿真结果多因子分析方法, 能够对仿真结果的各个影响因素(因子)进行分析, 确定哪些因素已被正确仿真, 哪些因素尚未被正确模拟, 从而指导仿真软件的编制.      

论加速可靠性增长试验(Ⅷ)试验的组织与实施

对加速可靠性增长试验的组织与实施，包括加速应力的选择，加速应力水平值及加速应力水平个数的确定，样本量的确定，分组数据区间长度的确定，试验终止时间的确定，可靠性增长模型的选择，图分析与数值分析的综合利用等问题进行了讨论。     

High acceleration, high performance solid state accelerometerdevelopment

This paper presents current accomplishments in the development of a high performance, high g, tactical accelerometer for use in the Advanced Kinetic Energy Missile (AdKEM) development program being conducted by the US Army Missile Command. The design goals of the accelerometer are to provide strapdown tactical navigation quality acceleration information throughout a 20 g soft launch phase, 1200 g boost phase, and low-g coast phase environment. The accelerometers must be able to provide acceleration measurements accurate enough to provide a navigational accuracy of 0.5 meter CEP at 500 meters. This translates to an accelerometer capable of measuring a 1200 g acceleration with a resolution of 1 milli-g. The AdKEM missile accelerometer and gyro outputs are used for control stability and midcourse guidance. The successful demonstration of this device offers a myriad of opportunities in both the commercial and military arenas. The operational environment and performance characteristics of the AdKEM accelerometer are presented. Crystalline quartz vibrating beam technology has been chosen for this accelerometer application to take advantage of solid state device characteristics. A solid state device with inherently digital output characteristics is desirable for strapdown navigation applications because of interface circuitry simplification, potential lower cost, inherent stability and longer storage life     

A new high performance multipurpose satellite tracking system

The European Space Agency's (ESA) multipurpose satellite tracking system is introduced. The system is able to perform accurate satellite ranging and Doppler measurements for a variety of mission types, i.e., from near-Earth satellites to deep space probes. The ranging signal is analyzed and described in an analytical manner from which the limits of the system performance are derived. A model of the overall system is presented and a few simulation results obtained thereby are compared with measurements performed with the ESA's Giotto and Hipparcos scientific missions     

A high performance automotive radar for automatic AICC

The paper describes a recent effort to design, build, and test a 77 GHz radar to be used for “intelligent” cruise control of automobiles. An analysis of requirements is given, design trade-offs are accounted for, and main features of prototypes in manufacturing are detailed. The radar has been thoroughly tested and evaluated both under “controlled” conditions and on roads, also in dense traffic. Results so far are very promising     

高负荷轴流压气机设计与试验验证

为了提高高负荷轴流压气机气动性能,探索高负荷压气机设计方法。首先,对高负荷压气机轴向载荷和参数分布进行研究与筛选优化;然后,利用二维正/反问题设计与分析方法优化压气机载荷展向分布;最后,利用三维流场分析方法进行精细分析,从而使高负荷压气机级间参数达到良好的匹配。将该方法应用于一台高负荷压气机设计中,并将试验值与计算结果进行了比较分析。结果显示:该技术有效地提高了压气机全工况的性能,使压气机各级工作在合理的参数下,相对于第4代发动机的压气机平均级压比提高了16%,效率提高了1%。     

大涵道比涡扇发动机高空台试验技术研究需求分析

分析了分开排气大涵道比涡扇发动机与小涵道比涡扇发动机,在结构、技术特点和对试验要求等方面的差异,并结合国内新建高空舱的设备特点和试验能力,提出了分开排气大涵道比涡扇发动机在该高空舱内试验前需开展的技术研究工作,明确了该大涵道比涡扇发动机开展首次高空台试验前应解决的技术问题。本研究对其他新型发动机高空台试验技术研究需求分析也具有重要的借鉴意义。     

提高航班正常率 CDM系统成效显著

11月1日华北地区流量管理及多机场放行协同系统(简称CDM系统)正式启用,目前已运行一个多月,统计数据显示,首都机场11月的航班平均正常率提高了3.21%,石家庄机场航班平均正常率提高了7.7%,天津机场航班平均正常率提高了3.88%,北京南苑机场航班平均正常率提高了2.83%,四机场航班正常率显著提高。本文将为您解读CDM系统的由来及其在国内外的发展与应用。空中交通管制部门的主要任务包括:间隔航空器、充分利用空域资源和避免管制员工作量过载。而航空公司的主要任务包括:保证航班正点起飞并准时飞抵目的地、确保旅客转机、航班     

仿真结果距离检验方法和TIC方法对比分析

针对仿真结果动态一致性的检验,将距离检验方法和TIC(Theil's inequality coefficient)方法进行了对比分析.距离检验方法可以在一定显著性水平下给出一致性检验的拒绝域,在时域内实现了定量检验.TIC方法的检验指标是TIC系数,经过研究发现,TIC系数的计算结果可以通过坐标原点的选取而进行人为调整,大大增加了误判的可能性,所以TIC方法既不能定量检验,也不能有效的定性检验.对比研究表明:距离检验方法不受量纲、坐标原点选取等因素影响,其检验结果具有更高的可信性.      

DGPS/IMU integration-based geolocation system: Airborne experimental test results

This paper addresses differential global positioning system (DGPS)/inertial measurement unit (IMU) integration-based geolocation system developed for airborne remote sensing cameras. First, we provide a brief review on sensor calibration, alignment and sensor fusion as background material of this research. After presenting those background material, as a main part of this paper we present a geolocation algorithm designed for an airborne imaging system. The geolocation system developed is tested through actual airborne experiments. For the verification of the geolocation system developed, we compare initial stationary states of the airplane before-taking off with states after-landing. From the actual test results, we find that it is critical to do an accurate time synchronization between IMU, DGPS, and airborne images, and to compensate for the data delay occurred during the network transfer.     

某型三叶螺旋桨的设计及性能试验

根据飞行速度、需用拉力、螺旋桨转速等参数,设计了某型飞机的三叶螺旋桨,获得了弦长和桨叶角沿着径向的分布.制造了三叶复合材料螺旋桨（直径为1.75m）,在螺旋桨试验台上测试了不同转速下螺旋桨的拉力.为了获得螺旋桨的动态性能,制造了螺旋桨的缩比模型（直径为0.96m）,在西北工业大学NF-3风洞的三元试验段测试了螺旋桨的气动性能数据,包括:拉力、扭矩、功率、效率.结果表明:螺旋桨最大效率为85.63%,所设计的三叶复合材料螺旋桨适用于螺旋桨需用功率为70kW左右的发动机（比如Rotax912）,提出的螺旋桨设计方法具有较好的应用价值.