嵌入式GPS/BDS实时精密单点定位方法     

韩啸  潘树国  赵庆 《测绘通报》2018,(2):99-102,163

实时性和动态性是精密单点定位面临的关键问题。本文基于实时轨道钟差改正产品,讨论了GPS/BDS实时精密单点定位数学模型及误差处理方法。搭建嵌入式软硬件平台,研制出一套具有实时GPS/BDS双系统高精度定位功能的嵌入式设备。测试结果表明,对于嵌入式GPS/BDS实时精密单点定位,静态条件下平面方向优于3 cm,高程方向优于8 cm;动态条件下平面方向优于12 cm,高程方向优于15 cm。  相似文献   

汶川Mw7.9地震余震序列触发机制研究     

申文豪  刘博研  史保平 《地震学报》2013,35(4)

余震触发机制的Dieterich解析模型被广泛应用于区域地震活动性的定量分析以及依赖时间的概率地震预测模型的建立等方面.基于滑移速率和状态相依赖的摩擦定律和弹簧-滑块模型,从Dieterich断层滑移速率方程出发,给出了静态应力扰动下触发地震的时钟提前或推后的近似解,从而明确地阐明了触发地震的产生机制与断层的演化过程密切相关,并与传统位错模型下库仑应力扰动时间提前或推后量作了比较.采用对数线性拟合方法求得了汶川Mw7.9主震后余震序列持续时间,符合Dieterich理论结果.以汶川余震序列为例,给出了两种不同的应力扰动模式在该余震序列中的应用.结果表明,经典Dieterich扰动解无法给出主震发生后即时余震数量的异常增加,而考虑主震前后剪应力速率变化的Dieterich分段解则可反映出余震发生率及个数随时间的演化特征.  相似文献   

Drivers of national climate policy     

Erick Lachapelle 《Climate Policy》2013,13(5):547-571

Patterns of national climate policy performance and their implications for the geopolitics of climate change are examined. An overview of levels of emissions performance across countries is first provided. Substantial changes in emissions trends over time are documented, notably with GHG emissions trajectories, which are shaped less and less by the developed/developing country divide. Various patterns of policy convergence and divergence in the types of policies states implement are then surveyed. Four broad types of explanation that may account for these trends are then explored: (1) variation in the institutional form of country-level governance regimes, (2) patterns of dependence on fossil fuel energy, (3) broad systemic differences among states (specifically in their population densities, carbon intensity, and per capita incomes, and (4) variations in the traditions of economic intervention by states. The article contributes to the growing body of work on comparative climate policy, and provides a first attempt at exploring the comparative politics of instrument choice. The analysis challenges the continued importance of a North–South divide for the future of climate policy, thus reinforcing a sense of the ‘new geopolitics’ of climate change. Some of the implications of the analysis for debates about the form of future international agreement on mitigation policy are also explored.

Policy relevance

The article contributes to the understanding of the variety of institutional conditions under which policy makers develop policy and thus the constraints and opportunities for the design of international agreements under these conditions.  相似文献   

Credible commitment in carbon policy     

Steffen Brunner  Christian Flachsland  Robert Marschinski 《Climate Policy》2013,13(2):255-271

In this article the problem of credible commitment in carbon policy is discussed. Investors favour long-term predictability of the policy, but without any external enforcement mechanisms a commitment made by a government can be withdrawn, leading to scepticism and lack of credibility. This results in increased market risks and investment hold-up. Regulatory uncertainty stems from (i) strategic interactions between government and firms, (ii) potential learning about climate damage and abatement cost and (iii) political volatility. Although commitment to future policy encourages private investment, it also imposes costs in the form of reduced flexibility to accommodate new information or preferences. The article reviews devices that may help policy makers raise the level of commitment while also leaving some room for flexible adjustments. In particular, legislation of a long-term governance framework, delegation to an independent carbon agency and securitization of investors' stakes in emission markets offer palliative approaches.  相似文献   

Sectoral approaches for a post-2012 climate regime: a taxonomy     

《Climate Policy》2013,13(6):652-668

Sectoral approaches have been gaining currency in the international climate debate as a possible remedy to the shortfalls of the Kyoto Protocol. Proponents argue that a sector-based architecture can more easily invite the participation of developing countries, address competitiveness issues, and enable immediate emissions reductions. However, given the numerous proposals, much confusion remains as to what sectoral approaches actually are. This article provides a simple, yet comprehensive, taxonomy of the various proposals for sectoral approaches. Based on the dual criteria of content and actors, three such types are identified and described: government targets and timetables; industry targets and timetables; and transnational technology cooperation. For each of these types, existing proposals and ongoing initiatives are discussed. In a second step, the article analyses the political landscape in which sectoral approaches are being debated, identifying the interests of their key advocates as well as the concerns of their critics. The Japanese government and energy-intensive manufacturing industries represent the main proponents of sectoral approaches to address the problems of carbon leakage and economic competitiveness. Developing countries, on the other hand, are wary of attempts to impose emissions reduction targets on their economies through sectoral target-setting. They, therefore, interpret sectoral approaches as sector-based forms of technology cooperation and technology transfer.  相似文献   

Building bridges to 2020 and beyond: the road from Bali     

HARALD WINKLER  SHAUN VORSTER 《Climate Policy》2013,13(3):240-254

What would the shape of a realistic, yet ambitious, package for the climate regime after 2012 look like? How do we obtain a package deal starting in Bali but building bridges to a post-2020 climate regime? A fair, effective, flexible and inclusive package deal has to strike a core balance between development and climate imperatives (mitigation, adaptation, dealing with the impacts of response measures, technology transfer, investment and finance) to create bargaining space and establish a conceptual contract zone. Within a continuum of possible packages, two packages in the contract zone are identified: ‘multi-stage’ and ‘ambitious transitional’. The latter is ambitious, combining domestic cap-and-trade for the USA, deeper cuts for Annex B countries, and quantifiable mitigation actions by developing countries. It is transitional as a possible bridge to a more inclusive regime beyond 2020. Multi-stage is defined around mechanisms by which countries move through increasingly stringent levels of participation, and must be based upon agreed triggers. Our assessment of political dynamics is that multi-stage is not yet in the political contract zone. Key to this is the absence of a ‘trigger from the North’, in that the largest historical emitter must act earlier and most decisively. But progress will also depend on continued leadership from Annex B countries, as well as more proactive, incentivized leadership in the South. Agreeing on the transitional stage is the critical next step in the evolution of the climate regime. Negotiating any package will require an institutional space for bargaining, political leadership and trust, and a clear time-frame.  相似文献   

时频系统中主备钟一致性保持方法的研究1   总被引：1，自引：0，他引：1  

卢建福  高玉平  林思佳  刘彪 《时间频率学报》2013,(4)

为保证主、备钟切换时时间信号的准确性和稳定性,开展了主、备钟一致性保持方法的研究。搭建了进行主、备钟一致性保持的实验系统,阐述了系统的原理,分析了不同钟差预测模型的效果,给出了计算备份钟频率补偿量的公式,测试了系统在不同控制周期下的同步水平。测试结果表明：采用本系统的主、备钟一致性保持方法,能够实现主、备钟间的最大时间偏差小于1 ns的指标,同时提高了备份钟的长期频率稳定度。  相似文献   

698nm窄线宽激光器研究进展     

任立庆  刘杰  高静  张林波  靖亮  董瑞芳  刘涛  李永放  张首刚 《时间频率学报》2012,35(2):70-75

窄线宽激光器在铯原子喷泉钟、光钟以及时间频率传递等方面有着重要的作用。主要介绍中国科学院国家授时中心开展的工作波长为698 nm窄线宽激光器的研究进展。实验中采用两级稳频方法将激光锁到初稳腔和高稳腔。通过第一级稳频,激光线宽为1.1 kHz;目前已初步实现了第二级稳频。通过逐渐优化第二级稳频,可以实现Hz量级线宽激光。  相似文献   

参考腔模式匹配及其在激光稳频中的应用     

马喆  刘杰  任立庆  刘涛  张首刚 《时间频率学报》2012,35(1):1-5

窄线宽激光器是光钟的核心部件,也是原子光精密测量的关键仪器。利用参考腔的功率反射率和功率透射率与损耗的关系给出了窄线宽激光器系统稳频中腔镜损耗的理论表达式。对腔镜的实际反射率与损耗进行了实验测量和计算。实验结果表明,优化模式匹配效率,可以进一步减小腔镜损耗。更重要的是,腔镜损耗的优化有助于提高稳频的锁定质量。  相似文献   

基于CORS网的卫星钟差完备性监测     

谷守周  秘金钟  党亚民  方书山 《测绘科学》2013,38(3):22-23

卫星钟差质量直接影响到高精度用户的定位结果,因此需对钟差实时监测,即为卫星钟差完备性监测,它是导航系统完备性理论体系中重要的组成部分。本文基于完备性监测的理念,利用CORS网的GPS观测值,利用多个基准站计算卫星钟差,分析同一卫星多个站上观测值的残差,确定各卫星钟差的可用性,若某一卫星的观测值残差与其他卫星残差有显著差异,且超过限值,则认为该卫星钟差质量较差,应给出示警信息,实现卫星钟差的完备性监测。最后针对河北省CORS网的观测数据,实现了卫星钟差完备性监测。  相似文献