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GPS/DR组合导航自适应Kalman滤波算法 总被引:2,自引:0,他引:2
针对GPS/DR组合导航Kalman滤波的异常扰动影响问题,引入了自适应滤波算法.给出了由预测残差确定自适应因子的过程.利用实测数据进行验证,结果表明无论是单因子自适应滤波还是多因子自适应滤波都能够很好地控制状态异常对滤波估值的影响,滤波精度均优于标准Kalman滤波导航解;而且因为多因子自适应滤波避免损失可靠的状态参数信息,较单因子自适应滤波,精度又有明显提高. 相似文献
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岩浆混合作用研究综述 总被引:5,自引:0,他引:5
本文详细阐述了近年来国内外对岩浆混合作用的研究进展,集中在混合作用的验证及地幔物质参与对混合作用的影响。从能量、物质运移的角度认识岩浆混合作用,以揭示上地幔、地壳的信息,并为认识区域构造一岩浆演化提供约束。综合归纳了岩浆混合作用主要的研究方法,系统总结了混合作用发生的规律及主要影响因素,并应用已有理论和数据进行简单的数值模拟,合理解释岩脉的不混合特征。作为壳一幔间物质与能量交换的重要形式,阐述了岩浆混合与底侵作用的关系,并介绍了常见的岩浆混合作用岩石成因模型。最后说明了岩浆混合作用今后的发展趋势和存在问题。 相似文献
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取自黄骅港防波堤两侧海区的7个无扰动柱状沉积物岩心的^137Cs示踪研究显示.该区^137Cs曲线可以分为3种类型:①不连续的^137Cs曲线(表层未检测到^137Cs),②连续的^137Cs曲线(表层检测到^137Cs),③未检测到^137Cs的曲线。^137Cs示踪的沉积速率结果显示:①NE向伸展的防砂堤截断原SE向的沿岸流后,造成了黄骅港防波堤两侧近岸差异性现代沉积过程,即堤北侧距岸约4km以内海区现代沉积速为0.69~1.12cm/a,堤南侧距岸约4km处的站位8以内无沉积物沉积;(2)防砂堤南侧的岸外10km、水深约-4m处,存在一个速率高达1.36cm/a的现代沉积中心。上述结果与前人的工作成果对比表明,黄骅港建港前后,现代沉积速率的空间分布特征发生了明显的变化,进一步说明与人类活动密切相关的地质环境变化主导了现在的地质环境变化.应当引起人们的更多重视。 相似文献
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N. Ya. Sotnikova 《Astrophysics》1996,39(2):141-152
Computer programs developed to study large-scale, transient gas structures in galaxies are described and test results are given. Gas-dynamic quantities are determined on the basis of a three-dimensional algorithm using so-called "smoothed particle hydrodynamics" (SPH). Preliminary calculations were made to simulate the formation of a gas ring around a spheroidal galaxy when it absorbs a low-mass, gas-rich companion, as well due to gas accretion during the flyby of a spiral galaxy of comparable mass. The evolution of tidal gas tails of disk galaxies is investigated.Translated from Astrofizika, Vol. 39, No. 2, pp. 265–284, April–June, 1996. 相似文献
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The variation in elemental depletions seen in diffuse clouds in the interstellar medium is shown to be consistent with the exposure of grains to weak shocks. Shocks remove a weakly bound layer of amorphous oxide material from refractory cores. Depletions are shown to be the result of the incorporation of elements in refractory cores formed during equilibrium condensation in high temperature sources together with accretion under low (T1000K) temperature conditions. Evidence is presented for the high temperature condensation of CaAlTi grains. In addition to refractory CaAlTi particels, a refractory condensate containing 20% of available Mg, 60% of Si and 90% of Fe is inferred from data on depletions. An amorphous layer with a composition (2MgO) (SiO) condenses on these cores. 相似文献
80.
A. T. Bazilevski N. N. Bobina V. P. Shashkina Yu. G. Shkuratov Yu. V. Kornienko A. Ya. Usikov D. G. Stankevich 《Earth, Moon, and Planets》1982,27(1):63-89
Aiming to study the relationship between Venus surface heights and surface roughness, the Pioneer Venus surface altitude map and map of r.m.s. slope in m-dkm scale have been analy sed for the Beta and Ishtar regions using a system of digital image processing. To integrate the data obtained, the results of geomorphological analysis of Venera 9 and 10 TV panoramas as well as gamma-spectrometric and photometric measurements were used. The analysis gives proof that Venera 9 and 10 landing sites represent geologic-morphologic situations typical of Venus, thus enabling the results of observations made at landing sites to be extended to large provinces. Apparently this conclusion is also applicable to the Venera 8 landing site. No strong relationship exists between the roughness of the surface and its altitude or the amount of a regional slope; neither for the Beta nor for the Ishtar region. A weak direct correlation observable for roughness-altitude pairs for the Beta region and roughness-altitude, roughness-slope pairs for the Ishtar region are quite obviously a consequence of regional roughness control, i.e. of an overall character of geological structure. On Venus the factors contributing to higher surface roughness on the m-dkm scale are, obviously, mostly volcanic and tectonic in their nature whilst those responsible for smoothing-out of the surface are chiefly exogenic. The rate of exogenic transformation of the Cytherean surface may be fairly high. On Venus, similarly as on the Earth, active tectono-magmatic processes have possibly taken place in recent geological epochs. One of the places where they are manifest is an extensive zone running from north to south across the Beta, Phoebe and Themis highlands. Within its limits occur both the process of basaltic shield-type volcanism and areal basalt effusions at low hypsometric levels accounting for the formation of lowland plains at the expense of ancient rolling plains. The basalts of the shield volcano Beta show some differences in composition compared to those of areal effusions at low hypsometric levels. The overall character of Cytherean tectonics in the recent geologic epoch is apparently block-type with a predominance of vertical movements. Against the background of the sinking of some of the blocks the other ones are rising and, possibly, such compensation upheavals have been responsible for the formation of the Ishtar region. 相似文献