共查询到20条相似文献，搜索用时 156 毫秒
1.
本文通过对天体测量仪器光子计数模拟资料的处理,比较了13种不同的平滑模型和两种定心算法对最终精度的影响;提出了利用频率域滤波和修正矩方法相结合的最佳处理方法;并对比较结果进行了多方面的讨论。 相似文献
2.
对于一颗在大气外层不可分辨的恒星,当其光线通过地球大气层后,恒星的星像光度呈高斯分布;而子午仪光子计数观测记录下与其星像光度相关的轮廓曲线。采用模拟光子计数观测方法,求得恒星星像直径的经验公式。利用恒星的子午仪光子计数观测资料,使用最小二乘估计方法,并考虑到模拟计算星像直径的经验关系式,可以求出恒星子午仪光子计数观测的实测直径。用该方法对一组星的观测资料,求出其平均星像直径为3″.2。 相似文献
3.
4.
5.
光子计数技术用于Ⅱ型光电等高仪观测系统 总被引：1，自引：0，他引：1
本叙述了Ⅱ型光电等高仪的一套完整的现代化观测系统，整个系统由IBM－286计算机进行实时控制、数据采集和结果处理，并且采用了光子计数的新技术，使光电等高仪的观测星等从原来的6^m.5提高到11^m.0。该系统已在上海天台、云南天台的Ⅱ型光电等高仪上正式使用，效果很好。 相似文献
6.
由于超区工作,郭守敬望远镜(LAMOST)光纤定位单元,在定位过程中可能发生碰撞。为了安全运行提高效率,需要有一个硬件碰撞识别处理系统。提出了一种采用脉冲信号计数的方法。利用延时程序在单片机1的I/O口产生3种同频率不同相位的脉冲。将这3种脉冲分别加在相邻的3个光纤单元的光纤架上,由单片机2的计数器累计在设定的时间段内光纤架上的脉冲数,计数结果由单片机2处理,如果计数结果在未发生碰撞的理论值范围内,则电机继续沿原方向旋转,否则说明光纤定位单元发生碰撞,电机将按原方向的反向进行转动。对此进行了仿真实验。 相似文献
7.
谭征 《紫金山天文台台刊》1995,14(2):146-158
本文对光子计数探测中堵塞漏计引起的非线性失真现象作了一些新的探讨相分析,提出了一套新的减少漏计的论证。该论证一旦实现,将会大大扩展光子计数探测的线性范围,进一步提高探测的灵敏度、信噪比和精度。 相似文献
8.
9.
本文报告了数据采集和控制软件ＣＭＵＯＰＰＳ的研制情况，这个软件是云南天文台密近双星研究组为泰国清迈大学天文台研制的光子计数式光电测光系统的专用配套软件。文中给出了硬件接口的性能及软件和硬件握手的方案，介绍了软件的总体概况，还说明了软件的使用环境和使用方法。最后给出了实验室测试和试观测过程中软件的运行情况及结果。 相似文献
10.
陕西天文台光电中星仪所获光子计数观测资料,用九点最小二乘平滑的办法来预处理,用权函数与观测量卷积办法定出中天时刻的估计量。在星像轮廓函数及噪声分布函数均已知的条件下,得到中天时刻的最佳无偏估计。对一组星观测资料,用最佳无偏估计方法得到其测时平均内部精度为5ms。 相似文献
11.
One of the most critical points in the detection of cosmic rays by neutron monitors is the correction of the raw data. The data that a detector measures may be distorted by a variety of reasons and the subtraction of these distortions is a prerequisite for processing them further. The final aim of these corrections is to keep only the fluctuations related to the real cosmic-ray intensity. To achieve this, we analyze data from identical neutron monitor detectors which provide a configuration with the ability to exclude the distortions by comparing the counting rate of each detector. Based on this method, a number of effective algorithms have been developed: Median Editor, Median Editor Plus, and Super Editor are some of the algorithms that are being used in the neutron monitor data processing with satisfactory results. In this work, a new approach for the correction of the neutron monitor primary data with a completely different method, based on the use of artificial neural networks, is proposed. A comparison of this method with the algorithms mentioned previously is also presented. 相似文献
12.
本文主要介绍GDJ打印经纬仪经光电改装后的系统特点及新的观测方法,并由此而获取的效益。 相似文献
13.
Ryszard Gabryszewski 《Planetary and Space Science》1997,45(12):1653-1655
An adaptation of Bielicki's method of reduction of old cometary micrometer observations of the comet-minus-star type to the PPM star catalogue is presented. A fully automatic utility is described which reduces old positions of stars to the coordinates in the PPM star catalogue for comet-minus-star astrometric observations. The reduction clears observations from systematic errors in old catalogues and decreases the mean error of observations. That may have implications for orbit improvement. The utility predicts new positions of stars in the PPM catalogue as needed and can also restore observations which have been previously rejected due to a selection criterion. It helps to get all data in one, coherent reference frame with maximum possible precision when there are lots of old and new observations of the same object. As an illustration, results of application of the utility to observations of comets 122P/de Vico and 109P/Swift-Tuttle are presented. 相似文献
14.
《Planetary and Space Science》2007,55(9):1031-1043
A new three-dimensional magnetohydrodynamic model of the coma of a comet has been developed and applied to simulations of a Halley-class coma using the solar-wind conditions of the Giotto flyby of Halley in 1986. The code developed for high-performance parallel processing computers, combines the high spatial resolution of smaller than 1 km grid spacing near the nucleus, with a large computational domain that enables structures nearly 10 million km down the comet tail to be modeled. Ions, neutrals, and electrons are considered as separate interacting fluids. Significant physical processes treated by the model include both photo and electron impact ionization of neutrals, recombination of ions, charge exchange between solar-wind ions and cometary neutrals, and frictional interactions between the three fluids considered in the model. A variety of plasma structures and physical parameters that are the output of this model are compared with relevant Giotto data from the 1986 Halley flyby. 相似文献
15.
A. P. Kornienko A. A. Stepanian Yu. L. Zyskin Yu. I. Neshpor V. P. Fomin V. G. Shytov B. M. Vladimirsky 《Experimental Astronomy》1993,4(2):77-86
The Cerenkov installation of the Crimean Astrophysical Observatory, consisting of two identical detectors, separated by 20m, are mounted in parallel for comparing the parameters of images. The average counting rate at one section is 35% higher than at the other. The number of coincident flashes make up 55% for one section and 76% for the second section. The comparison of parameters of coincident events shows high correlation of centroid positions (correlation coefficient r=0.98), of length (r=0.70), orientational angle (r=0.64). The correlation of width parameters is considerably lower (r=0.44).Since the coincident flashes at the two sections correspond to the same EAS their image parameters must be the same or very close. Hence the correlation coefficient between identical parameters of coincident flashes will characterize the quality of equipment and the method of observational data processing. 相似文献
16.
17.
The contribution to the main detector counting rate from photons scattered and reemitted from the collimator walls is considered in two particular cases, that of our group's old S-11 rocket data and OSO-III. We find that the S-11 results are not changed appreciably white our consideration of the OSO-III results has lead us to the belief that these results should be strongly modified. 相似文献
18.
为了获得稳定、可靠的卫星电视时间比对数据,成功研制了以秒信号提取器为主要部件的新一代卫星电视时间解调器。介绍了秒脉冲信号提取器的设计原理,详细阐述了钳位电路、采样保持电路和数字延迟电路的设计思路。对采用新的解调器和采用旧的解调器的卫星电视秒信号监测系统所得到的比对数据进行了分析,结果表明新的电视时间解码器的性能得到明显提高。 相似文献
19.
1986年3月8日哈雷彗星发生一次Ⅰ型彗尾断尾事件,新主尾与老主尾的风差角不同。本文对我们所摄哈雷彗星大尺度底片,用光度测量方法定出主尾轴的视风差角;并且用导出的公式,算出相应的真风差角。最后,对所得结果进行一些讨论。 相似文献
20.
We have defined new algorithms for the data processing of a satellite geodesy mission with gradiometer (such as the next European
mission GOCE) to extract the information on the gravity field coefficients with a realistic estimate of their accuracy. The
large scale data processing can be managed by a multistage decomposition. First the spacecraft position is determined, i.e.,
a kinematic method is normally used. Second we use a new method to perform the necessary digital calibration of the gradiometer.
Third we use a multiarc approach to separately solve for the global gravity field parameters. Fourth we use an approximate
resonant decomposition, that is we partition in a new way the harmonic coefficients of the gravity field. Thus the normal
system is reduced to blocks of manageable size without neglecting significant correlations. Still the normal system is badly
conditioned because of the polar gaps in the spatial distribution of the data. We have shown that the principal components
of the uncertainty correspond to harmonic anomalies with very small signal in the region where GOCE is flying; these uncertainties
cannot be removed by any data processing method. This allows a complete simulation of the GOCE mission with affordable computer
resources. We show that it is possible to solve for the harmonic coefficients up to degree 200–220 with signal to error ratio
≥1, taking into account systematic measurement errors. Errors in the spacecraft orbit, as expected from state of the art satellite
navigation, do not degrade the solution. Gradiometer calibration is the main problem. By including a systematic error model,
we have shown that the results are sensitive to spurious gradiometer signals at frequencies close to the lower limit of the
measurement band. If these spurious effects grow as the inverse of the frequency, then the actual error is larger than the
formal error only by a factor ≃2, that is the results are not compromised. 相似文献