印度航天技术发展概况及其主要经验

本文首先介绍了印度航天技术发展的概况，包括航天组织、通信卫星、遥感卫星、运载火箭和空间探测等的发展概况。接着分析了印度发展航天技术的主要经验：结合印度的国情，促进印度经济持续发展；引进国外技术和发展自己的系统相结合；做好综合协调，避免重复和大力促进产业化。最后，对印度和我国的航天技术发展作了简单的比较。     

Valuing Unpaid Child Care in the U.S.: A Prototype Satellite Account Using the American Time Use Survey

This paper builds on previous satellite accounts that treat households as production units, but challenges their measurement and valuation of time devoted to child care, making a case for the inclusion of supervisory child care time that does not overlap with other productive activities. We also suggest several other methodological refinements for estimates based on analysis of data from the American Time Use Survey: application of a vector of specialized replacement cost wage estimates for different child care activities rather than a single wage, and adjustments for the ratio of children to adults present and for the educational attainment of caregivers. Our estimates of the value of child care alone in 2004 and 2010 exceed previous estimates of the value of all non‐market household production in the U.S. The end result is an upward adjustment of Gross Domestic Product by about 43 percent compared to previous adjustments of about 26 percent.     

星间链路技术的研究现状与发展趋势

星间链路技术是提高全球卫星导航系统的精度和自主导航能力的一项关键技术。介绍了全球主要卫星导航系统星间链路的建设情况,综述了国内外关于星间链路的重要研究,包括星座的特性分析、星间链路的构建准则、星间链路的拓扑分析、星间链路传播信号的设计以及星间链路信号的发射和接收等,指出了目前研究的侧重点,展望了星间链路的发展趋势和未来的研究方向。相关内容可为星间链路的进一步研究提供参考。     

“北斗”B2频段导航信号伪码跟踪性能分析

与传统卫星导航信号体制不同,新一代“北斗”B2频段导航信号采用了交替二进制偏移载波调制（AltBOC）体制,因此伪码跟踪性能也与传统信号体制有较大差异。首先介绍了AltBOC调制信号原理及特点,然后根据码跟踪精度理论比较了新型调制信号与传统信号体制的性能差异,分析了不同鉴相器时B2频段信号的码跟踪误差,并对不同相关器间隔、环路带宽、前端带宽、载噪比环境条件下的伪码跟踪误差进行了仿真分析。仿真结果表明,提高信号载噪比、射频前端带宽或减小相关器间隔、环路带宽均能减小码跟踪误差。研究结果对新一代“北斗”导航信号新体制性能的评估以及“北斗”导航接收机的系统设计具有一定指导意义。     

一种准实时目标区域监视星座应用模式分析

利用低轨卫星对特定目标区域进行观测和监视在军民领域都具有很重大的意义,在系统设计 中,需要重点考虎如何对所获取的信息进行实时传输并高效处理。介绍了一种准实时目标区 域监视星座应用模式,进 行了理论分析,并以仿真说明了该模式下监视信息的传输具有较高的时效性,优于传统的星 座 应用模式。最后分析了该应用模式下涉及到的多星接入问题。     

文化分割、要素错配与区域经济增长

以汉语方言为例,从要素错配的视角考察文化分割影响区域经济增长的内在机制,进而采用修正后的全球夜间卫星灯光数据和各地区的方言多样化指数,实证考察文化分割对区域经济增长的影响效应。研究结果表明：以汉语方言为代表的文化分割显著抑制了区域经济增长,且这种抑制作用主要体现在中西部地区;文化分割阻碍了劳动力和资本等要素的优化配置,进而对区域经济增长产生不利影响。所得研究结论有助于进一步厘清文化因素与经济增长之间的关系,也为从非正式制度角度探求促进中国经济增长的动力机制提供了有益启示。     

Integrated Environmental and Economic Accounting: An Application to the Forest Resources in India

Forests contribute to the economy in several ways. While forests are a source of timber with market values, they also influence local and regional climate, preserve soil cover on site, and in the case of watersheds, protect soil downstream from floods –functions, which are not in the production boundary of SNA. Further, the net value added in forestry sector does not reflect sustainability of forest resources, because it ignores the consumption of natural capital (depletion) that occurs when forests are harvested or converted to other uses. The only costs of depletion considered in the national accounts are the extraction costs and records the potential loss in forest wealth as other changes in assets that have no effect on Gross Domestic Product (GDP). The study tries to incorporate forest resources into the national accounts and adjust the Gross Domestic Product (GDP) for the depletion of forest capital, using the Satellite System of Integrated Environmental and Economic Accounting (SEEA). The value of net accumulation (positive or negative) of forests is calculated and the net Domestic Product is adjusted for the depletion of the forest resources to get Environment adjusted Domestic Product (EDP). The results show that the EDP equals 98.4% of the adjusted net domestic product in 1993–1994. A proper accounting framework would better reflect not only the long term value of the state's natural wealth but also its immediate contribution to the state economy in the current accounts.     

LEO卫星通信信道动态模型建立与仿真

为了建立一个能够反映实际LEO卫星通信信道动态传播特性的仿真模型,在深入研究目前国内外常用的卫星移动通信信道统计模型的基础上,提出了一种动态Loo模型。仿真结果表明:相对于Loo模型,进一步增强了对实际信道动态传播特性的仿真能力。     

灾害管理领域中的卫星遥感技术和实践

本文主要介绍了法国和欧洲的卫星遥感资源和技术,及包括在减灾防灾方面的具体实践。同时,对全球其他对地观测组织和计划进行了简要介绍。在空间技术方面拥有强大实力的法国整合了灾害管理体系中的卫星遥感技术。     

一种中继卫星系统多址应用设想

通过中继卫星系统中码分多址（Code Division Multiple Access,CDMA）/ 时分多址（Time Division Multiple Access,TDMA）能力、实现复杂度、容量等方面的分析,结合中继卫星系统传输数据在固定站点接入的特点,设想了一种前向采用同步CDMA、返向采用TDMA的混合多址应用方式。该方式充分利用了CDMA和TDMA方式的优点,巧妙地利用前向通道实现了TDMA的时隙同步,解决了CDMA方式下存在的多址干扰、远近效应、用户数扩展受限以及TDMA方式下的复杂时隙同步等问题,且应用灵活,实现简单,多用户数扩展性好,在工程应用上具有一定的参考意义。