GNSS three carrier ambiguity resolution using ionosphere-reduced virtual signals

This paper presents a general modeling strategy for ambiguity resolution (AR) and position estimation (PE) using three or more phase-based ranging signals from a global navigation satellite system (GNSS). The proposed strategy will identify three best “virtual” signals to allow for more reliable AR under certain observational conditions characterized by ionospheric and tropospheric delay variability, level of phase noise and orbit accuracy. The selected virtual signals suffer from minimal or relatively low ionospheric effects, and thus are known as ionosphere-reduced virtual signals. As a result, the ionospheric parameters in the geometry-based observational models can be eliminated for long baselines, typically those of length tens to hundreds of kilometres. The proposed modeling comprises three major steps. Step 1 is the geometry-free determination of the extra-widelane (EWL) formed between the two closest L-band carrier measurements, directly from the two corresponding code measurements. Step 2 forms the second EWL signal and resolves the integer ambiguity with a geometry-based estimator alone or together with the first EWL. This is followed by a procedure to correct for the first-order ionospheric delay using the two ambiguity-fixed widelane (WL) signals derived from the integer-fixed EWL signals. Step 3 finds an independent narrow-lane (NL) signal, which is used together with a refined WL to resolve NL ambiguity with geometry-based integer estimation and search algorithms. As a result, the above two AR processes performed with WL/NL and EWL/WL signals respectively, either in sequence or in parallel, can support real time kinematic (RTK) positioning over baselines of tens to hundreds of kilometres, thus enabling centimetre-to-decimentre positioning at the local, regional and even global scales in the future.     

Electrical aerosol spectrometer of Tartu University

The electrical aerosol spectrometer (EAS) of the parallel measuring principle at Tartu University is an efficient instrument for rapid measurement of the unstable size spectrum of aerosol particles. The measuring range from 10 nm to 10 μm is achieved by simultaneously using a pair of differential mobility analyzers with two different particle chargers. The particle spectrum is calculated and measurement errors are estimated in real time by using a least-squares method. Experimental calibration ensures reliability of measurement. The instrument is well suited for continuous monitoring of atmospheric aerosol.     

DAS24-3B数据采集系统采集控制模块的工作原理

DAS24-3B是中国科学院地质与地球物理研究所研制的宽频带地震数据采集系统。采集控制模块是该系统的重要组成部分。本文阐述了控制模块的工作原理，介绍了DAS24-3B系统的基本组成和采集器工作过程，并给出该系统如何与笔记本端应用程序界面通讯和联络的操作建议，使该系统能够在工作中发挥更大的作用。     

穗城的环境与房地产业互动发展

根据穗城的城市环境的改善和房地产业发展的实际情况，运用大量的论据，论证了穗城的环境和房地产业是互动发展的关系，指出在今后城乡一体化的格局状态下，其互动发展关系将更为密切，分析了互动发展过程中产生的负面影响，并就此提出一些建议。     

无验潮模式下的GPS水下地形测量技术

传统的水下地形测量模式定型于利用GPS测定水底点的平面位置,利用测深仪测定水底点的深度,附之以瞬时潮位资料,获得点位的高程。这种模式在上述条件具备的情况下,可取得完满的结果。但当验潮条件不具备时,该模式将不能获得测点的高程。为了弥补这一缺陷,简化工作流程,提高水下地形测量的精度,本文提出了一种无验潮模式下的水下地形测量思想,该思想不用专门测定潮位,而直接利用GPS的RTK测量技术,辅之以姿态测量和补偿,从而获得高精度的水底点高程。该方法被验证是正确的,希望进一步推广应用。     

三维实景地图生产与应用

实景地图近年来发展迅速,在日常生活中应用广泛,如旅游景点、宾馆、银行、政府服务中心等的空间位置查询、服务内容介绍等。实景地图的生产方法、生产流程有多种多样,产品质量参差不齐。目前,利用轻型无人机航空摄影系统实现三维全景地图生产,生产方式方便、高效且质量较好。该文介绍了生产三维实景地图的无人机系统及三维实景地图生产方法与过程,通过采用无人机系统实景地图的生产实例,讲述了实景地图应用现状、发展前景及存在的问题。     

不动产空间数据二三维一体化存储设计与应用探讨

通过对不动产空间数据和ArcGIS的GeoDatabase数据模型的分析，设计了不动产登记空间数据成果二三维数据统一存储的规则和方法，从而为不动产登记成果的二三维系统应用提供了数据支撑。     

Whole-rock chemistry of the Gameleira I uranium deposit,Lagoa Real,Brazil

The Lagoa Real uranium (U) province, referred to as Lagoa Real, is located in the state of Bahia, north-eastern Brazil. Lagoa Real has ∼112,000 metric tonnes and average grade of 2700 ppm of U₃O₈, being one of the largest U deposits in the world and the largest in Brazil. Despite its economic and strategic importance, there are gaps in the geological knowledge of the Lagoa Real U deposits. One of them is the lack of extensive whole-rock chemical data sets. Here, we present whole-rock chemical analyses for major and trace elements, including the rare-earth elements (REE), from barren country rocks to uraniferous ore shoot, systematically sampled from an exploratory drill hole. The chemical data indicate that albitite rocks, with and without uraniferous mineralisation, cannot result from sodic syenitic magmatism, as proposed by recent studies. Petrographical and geochemical evidence supports the previously suggested concept that the Lagoa Real albitite rocks resulted from sodic metasomatism of the granitic country rock, known as the São Timóteo granite. Their ore-mineral assemblages and geochemical characteristics are similar to albitite-hosted U deposits worldwide.     

SPOT图象的解析立体测图

本文讨论了适合于SPOT图象的用光束法平差解算外方位元素的数学模型;介绍了在国产解析测图仪APS—1上进行SOPT图象立体测图的方法;研究了SPOT投影方式的实时循环程序LOOP及SPOT图象的测图软件包。     

微气象自动观测网

本文介绍利用计算机和通讯技术,建立局地网络的微气象观测系统,实现气象数据的自动采集、无线传输和集中实时处理。整个系统由一个中心站和五个(或更多)观测子站组成,是一个点到点的通讯网络。该系统为研究不同下垫面地气相互作用的观测实验提供了手段和方便。整个系统分两部份介绍,本文作一总体概述,第二部份说明数据采集和无线传输的具体实施。