基于SUT-EKF的DGPS/DR 组合定位算法     

石杏喜  王铁生  黄波  赵春霞 《测绘学报》2010,39(5):528-533

针对基于DGPS/DR的移动机器人组合定位问题，采用一种尺度无迹变换扩展卡尔曼滤波(SUT-EKF)算法，由于组合定位系统中的状态方程是非线性的，并且观测方程是线性的特点，将SUT预测移动机器人位姿，利用EKF融合最新观测值更新机器人位姿，该算法在状态预测阶段避免了计算Jacobian矩阵，从而有效地减小了线性化对非线性系统误差的影响。仿真结果表明，该算法具有较好的滤波精度和稳定性，为实现DGPS/DR组合定位系统提供了一种有效可靠的途径。  相似文献   

A photometric study of two recently discovered,contact binaries-II: UCAC4 479-113658 and UCAC4 479-113711     

《New Astronomy》2019

In a previous paper, we have presented photometric studies of four recently discovered contact binaries (Djurašević, et al., 2016; hereafter Paper I) that were observed by the 1.88 m telescope of the Kottamia Astronomical Observatory (KAO) in Egypt. In this paper we continue studying two more recently discovered, by some of us, contact binaries UCAC4 479-113658 and UCAC4 479-113711, and analyze their light curves to determine orbital and physical parameters using the modeling program of G. Djurašević as in Paper I. The analysis shows that the two systems are W UMa contact binaries of late type main-sequence stars with a bright spot on the secondary less massive cool star of the first system; and spot on each component of the later system. We also conclude that both systems are most likely to be of the A-type class.  相似文献   

Interpretation of no radio pulsar inside supernova 1987A: The high plasma cut-off frequency by the remnant media     

《New Astronomy》2019

Three decades have passed since the supernova SN 1987A was observed in the Large Magellanic Cloud, inside which the product is most likely a neutron star (NS) formed in the core collapse explosion.Although lots of observations with sensitive radio telescopes have taken place, astronomers have not yet detected any evidence for a radio pulsar around the remnant of 1987A. To investigate pulsars inside the SN remnants, we calculate the cut-off oscillation frequency of the plasma around the presumed NS inside SN1987A, as shown to be about 33 GHz at present (2018 CE), which is much higher than the favorite “searching window” (e.g. L-band ∼ 1.4 GHz) of radio pulsar surveys that have been commonly exploited by astronomers. Since radio waves with frequencies lower than the plasma cut-off frequency cannot penetrate the SN remnant media, we suggest that astronomers use higher frequency bands to search for a pulsar in SN 1987A.Furthermore, with the expansion of SN remnant media, we find that the plasma cut-off frequency can decay to the L-band (1.4 GHz) in the future. The strategy of finding a pulsar of SN 1987A is that either the high frequency bands of radio telescopes, or the high energy detections at Gamma-ray and X-ray bands by space satellites are applied.  相似文献   

巡飞弹组合导航系统误差补偿及可靠性研究     

吴有龙 《测绘学报》2018,47(9):1294-1294

正巡飞弹是先进导弹技术和无人机技术等相结合的产物,能够快速抵达目标区域,执行集巡逻飞行,侦察监视等多功能于一体,是满足未来信息化作战需求的智能化弹药。由于巡飞弹需要长时间在恶劣环境下工作的特点,改善弹载导航系统的定位精度和可靠性对提高巡飞弹的系统性能非常关键。为此,本文研究了低成本弹载  相似文献   

Editorial Board     

《Atmospheric Research》2003,66(3):IFC

  相似文献   

The Icelandic debate on the case for a fishing fee: a non-technical introduction     

《Marine Policy》2001,25(4):303-312

Research by J.D. Sachs and A.M. Warner, indicates that resource-rich countries are less successful in terms of economic growth than are resource-poor countries. The question of what measures Icelanders need to take to prevent their fishery wealth from limiting economic growth is posed. The main body of the essay discusses arguments for a fishing fee. The principal arguments for a fishing fee are listed. One type of argument concerns flexibility, with a view to possibly introducing other forms of management or altering the distribution of profit in the future. Another type of argument concerns equity and fairness, contending that having a fishing fee makes it easier to ensure that the entire nation enjoys the benefit of the resource. A third type of argument is connected to risk-management, maintaining that, if properly arranged, a fishing fee would make it possible to offer vessel operators an indirect insurance policy which otherwise would not be available to them. The fourth type of argument concerns counter-cyclical policy and the problem of co-habitation of the fishery industry and other export industries and refers to the possibility of wage earners and/or taxpayers being forced (or tempted) to apply general policy instruments to secure a portion of the fishery rent. The general measures available to obtain a piece of the fishery rent share a common failing: their use unavoidably increases costs for other sectors of industry and thus limits possibilities for growth in those sectors and links their performance to fisheries performance. Then there are arguments for neutrality, based on the idea that the so-called resource rent taxes should not affect the use of the factors of production. Finally, there are economic growth arguments, which can be linked to theories of rent-seeking and Dutch disease.  相似文献   

一种遥感图像信噪比评估和度量准则     

傅鹏  孙权森  纪则轩  陈强 《测绘学报》2013,(4):559-567

对遥感图像信噪比的研究,能够很好地反映在轨运行的不同卫星遥感器辐射性能的变化与衰退情况。由于在轨成像环境的差异,如果直接比较不同遥感图像间的信噪比关系,将与实际结果产生较大分歧。通过对遥感图像进行图像块划分、匀值图像块选取以及图像灰度值与成像时传感器入瞳辐亮度的关系转换,提出一种遥感图像间信噪比的评估和度量准则,以进行不同遥感图像信噪比的比较,实现全自动的信噪比评估及度量。并对我国卫星传感器在不同时期所成图像信噪比的关系进行分析,验证该信噪比评估和度量准则的可靠性。  相似文献   

The density functional study of the stabilities, bond characters, static linear polarisabilities, and aromaticities of the `in-out'' isomerism H_n-60@C_nH₆₀ (n=70, 72, 74)