基于GPS和WiFi的室内外定位系统的设计与实现

经济和科技高速发展的中国,基于GPS的定位技术和基于WiFi的定位技术已发展成熟。在有14亿人口的中国,人们的思想观念发生了巨大变化,人口老龄化越来越严重,老人和小孩等弱势群体走失事件频发。因此,借助定位技术缓解这种现象十分必要。借助定位信息,不仅可以缓解老人小孩走失问题,而且可以实现前签到等功能。定位技术的应用范围和发展前景非常广阔。     

基于CORS系统下GPS测量技术在地质测绘中的应用

GPS测量技术在测绘领域中的应用价值相当突出,有着不可替代的作用和地位。同时,基于CORS系统下GPS测量技术因为具备精准定位、高效率定位等特点,在行业当中被许多人士认可。对此,为了更好的提高GPS测量技术的应用价值,详细分析基于CORS系统下GPS测量技术,希望可以今后相关工作者提供理论性帮助。     

Complementary Kalman Filter as a Baseline Vector Estimator for GPS-Based Attitude Determination

The Global Positioning System (GPS) offers the interferometer for attitude determination by processing the carrier phase observables. By using carrier phase observables, the relative positioning is obtained in centimeter level. GPS interferometry has been firstly used in precise static relative positioning, and thereafter in kinematic positioning. The carrier phase differential GPS based on interferometer principles can solve for the antenna baseline vector, defined as the vector between the antenna designated master and one of the slave antennas, connected to a rigid body. Determining the unknown baseline vectors between the antennas sits at the heart of GPS-based attitude determination. The conventional solution of the baseline vectors based on least-squares approach is inherently noisy, which results in the noisy attitude solutions. In this article, the complementary Kalman filter (CKF) is employed for solving the baseline vector in the attitude determination mechanism to improve the performance, where the receiversatellite double differenced observable was utilized as the measurement. By using the carrier phase observables, the relative positioning is obtained in centimeter level. Employing the CKF provides several advantages, such as accuracy improvement, reliability enhancement, and real-time assurance. Simulation results based on the conventional method where the least-squares approach is involved, and the proposed method where the CKF is involved are compared and discussed.     

A derivative UKF for tightly coupled INS/GPS integrated navigation

The tightly coupled INS/GPS integration introduces nonlinearity to the measurement equation of the Kalman filter due to the use of raw GPS pseudorange measurements. The extended Kalman filter (EKF) is a typical method to address the nonlinearity by linearizing the pseudorange measurements. However, the linearization may cause large modeling error or even degraded navigation solution. To solve this problem, this paper constructs a nonlinear measurement equation by including the second-order term in the Taylor series of the pseudorange measurements. Nevertheless, when using the unscented Kalman filter (UKF) to the INS/GPS integration for navigation estimation, it causes a great amount of redundant computation in the prediction process due to the linear feature of system state equation, especially for the case with system state vector in much higher dimension than measurement vector. To overcome this drawback in computational burden, this paper further develops a derivative UKF based on the constructed nonlinear measurement equation. The derivative UKF adopts the concise form of the original Kalman filter (KF) to the prediction process and employs the unscented transformation technique to the update process. Theoretical analysis and simulation results demonstrate that the derivative UKF can achieve higher accuracy with a much smaller computational cost in comparison with the traditional UKF.     

基于Android平台的路径日记系统开发与设计

随着世界信息产业和通讯设备制造产业的迅猛发展,手机已经成为人们日常生活中不可缺少的一部分。智能手机日益趋向于移动智能综合服务平台方向的发展。可以预想在未来的世界,手机将为人们提供移动办公、信息分享和获取、电子支付、游戏娱乐等等的服务,而地图导航就是其中一个非常重要的应用服务。     

GPS技术下的露天矿山爆破设计及布孔

针对某露天铁矿布孔方式及弊端，该矿山引进GPS技术并将其应用到矿山爆破设计和布孔中，在现场进行实验研究。结果表明，使用了GPS技术进行布孔，可以极大地提高孔位的布设精度，且操作简便，工作效率较之前也有较大的提高，满足了矿山精细化爆破要求，使得最终的爆破效果得到改善。据现场统计，最终爆破大块率降低40%，减少了处理大块等待时间，满足露天矿山采装的要求，获得了良好的经济效益。     

桥梁工程首级控制网测量关键技术探讨

首级控制网测量是桥梁工程顺利对接的关键技术之一，为保证桥梁工程施工质量,必须建立高精度控制网。根椐国家测量规范要求,结合某桥梁工程实例，探讨了首级控制网布设过程中的布网要求,以及平面控制测量和高程控制测量的关键技术及方法。经工程检验,该控制网布测方法能有效满足工程精度要求，对类似工程具有较强的操作性和借鉴意义。     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

3S技术在日本筑波山梅林公园规划上的应用

以日本筑波山梅林公园规划为例,总结了利用3S技术进行园林规划的方法及其起到的作用,并阐明了如何将得到的经验教训结合我国国情,推动我国相关方面的发展进程.     

用多普勒积分检测周跳

对多普勒积分法探测周跳的基本原理进行了阐述，对数值积分的步长和拉格朗日多项式的阶数进行了数值试验，说明步长为1s、阶数取7时最适当。对多普勒积分探测周跳的精度进行理论分析，在实测数据中模拟周跳进行了模拟周跳探测数值试验，结果表明，理论分析结果和试验结果相同，即随着采样间隔的增大，探测周跳的精度降低，当要探测1周的周跳时，采样间隔应该小于4s。