Position prediction is the basis of guiding radar to seek, capture, and track space targets, although there’s a risk of insufficient accuracy for narrow beam radar due to the influence of orbit determination and propagation error. Since the along-track error is the main factor that affects the accuracy of position prediction, this paper proposed a Constant Elevation Search (CES) method for narrow beam radar, based on the idea of along-track error compensation, to seek and capture transit targets. With along-track error estimation, all possible positions on a specified elevation can be observed, thus the success rate of capturing transit targets will be improved. Simulation shows that when the position prediction method fails, the CES method still works. 相似文献
Immersed tube tunnels are usually placed on soft soil layers in cross-sea tunnelling engineering. Owing to the influence of stratum conditions and slope design, the longitudinal distribution of substratum layers is generally uneven. Thus, the inhomogeneous deformation of the element-joint becomes the key factor in the failure of the immersed tube tunnel. Therefore, a corresponding calculation method for joint deformation is needed to explore the deformation law of immersed tube tunnels. By constructing a three-section immersed tube tunnel analysis model (TTM), the relationship between the two types of deformation of the immersed tube tunnel structure in a longitudinal nonuniform soft soil foundation is described, and the deformation characteristics of the immersed structure under different boundaries are discussed. Based on the mechanical behaviour of the joint and foundation, according to the Timoshenko beam on the Vlasov two-parameter foundation (VTM), considering the tidal cyclic load during the operation and maintenance period, an example analysis is given. Moreover, the deformation characteristics and development trend of the immersed tube tunnel under the influence of different soil layers are discussed. The obtained results have a certain guiding significance for the deformation calculation of immersed tube tunnels.
The relationship between economic development and energy consumption is revealed by employing cointegration theory, the index decomposition method, and a log-linear regression approach based on a case study of Jilin Province, China. The results suggest: 1) the economic development and energy consumption are interdetermined, whose relationship is positive and long-term. The economic development is highly depending on the energy in Jilin Province. 2) Under the condition of other unchanged factors, the change of industrial energy efficiency contributes to the energy saving, while that of industrial structure increases the energy consumption. 3) The industrial structure change enhances the energy intensity, but the energy utility efficiency change lowers it. From the view of contribution to the energy consumption, the contribution of industrial structure was more than that of the energy utility efficiency in 2000-2011. 4) In 2000-2011, the comprehensive energy intensity change and hydroelectricity energy intensity change were related to all industrial structures' change, and the influencing factors about structure of oil energy intensity change were more than those of coal energy intensity change; from the impact degree, agricultural proportion decreased exerted an positive and greater effect on lowering the energy intensity of comprehensive energy and hydroelectricity, and industrial one did on coal and natural gas. Some conclusions can be drawn as follows: the major way to promote the coordinated development of the industrial economy and energy consumption is to optimize the industrial structure by increasing the proportion of the tertiary industry and low energy consumption industrial sectors and to enhance the energy utility efficiency. 相似文献
This paper presents a novel approach for assessing the precision of the wet refractivity field using BDS (BeiDou navigation satellite system) simulations only,GPS,and BDS+GPS for the Shenzhen and Hongkong GNSS network.The simulations are carried out by adding artificial noise to a real observation dataset.Instead of using the δ and σ parameters computed from slant wet delay,as in previous studies,we employ the Bias and RMS parameters,computed from the tomography results of total voxels,in order to obtain a more direct and comprehensive evaluation of the precision of the refractivity field determination.The results show that:(1) the precision of tropospheric wet refractivity estimated using BDS alone (only 9 satellites used) is basically comparable to that of GPS; (2) BDS+GPS (as of current operation) may not be able to significantly improve the data's spatial density for the application of refractivity tomography; and (3) any slight increase in the precision of refractivity tomography,particularly in the lower atmosphere,bears great significance for any applications dependent on the Chinese operational meteorological service. 相似文献
International organizations sometimes institutionalize country groupings by specifying differentiated commitments that may, in turn, affect negotiation dynamics. Drawing on incentive-based and socialization arguments, we develop a “constructed peer group” hypothesis suggesting that by creating these groups those organizations may actually construct new lines of confrontation over and above the substance-based disagreements existing between countries. This generates a particular type of path dependence, rendering broad-based international agreements more difficult in the future.We analyze this question at the example of the United Nations Framework Convention on Climate Change's increasingly politicized split between Annex I and non-Annex I countries. Using a self-coded dataset of country oral statements during the negotiations between December 2007 and December 2009 we assess whether Annex I membership influences a country's stance toward other countries’ arguments, while controlling for country characteristics that may drive their preferences and the affiliation to Annex I. We find that the split between Annex I and non-Annex I has indeed influenced negotiation behavior and amplified the divide between developing and industrialized countries in the climate negotiations. 相似文献