A real-time inertial-aided cycle slip detection method based on ARIMA-GARCH model for inaccurate lever arm conditions

GPS Solutions - The GPS satellite transmitter antenna phase center offsets (PCOs) can be estimated in a global adjustment by constraining the ground station coordinates to the current International...     

WiFi指纹定位的一种新组合算法

探讨AP选取策略和贝叶斯位置估计算法对基于RSS的WiFi室内定位技术位置估计精度的影响。国内外学者分别对AP选取算法和贝叶斯位置估计算法进行了大量的研究。为了进一步深入研究不同算法的优劣性,利用组合优化的思想对不同算法进行组合,通过找出最优算法组合从而提升WiFi室内定位系统的性能。基于互信息最小化的AP选取策略和考虑AP相关性的贝叶斯位置估计算法,提出一种新的WiFi指纹定位组合算法。实验分析表明:新算法具有良好的实用性和定位性能。     

地理信息安全技术研究进展与展望

随着地理信息应用的深入,精度高、涉密广的地理信息安全保护要求与现阶段经济发展对地理信息共享需求的矛盾日益尖锐,如何在安全的前提下促进地理信息最大程度的共享已成为目前迫切需要解决的重要问题,亟须可靠的技术保护地理信息安全。本文综述了近几年来地理信息安全技术的进展,包括将数据转变为密文的加密技术、具有版权保护和溯源追踪作用的数字水印技术、能够控制时间和权限的安全控制技术、可以降低数据精度和删除涉密属性的保密处理技术以及防止篡改和可认证的区块链技术。然后,论述了地理信息安全技术在地理信息安全防护中的应用。最后,展望了地理信息安全技术的未来发展方向和进一步需要解决的关键问题。     

基于GIS的机场净空管理系统设计与实现

机场净空保护是确保机场周边区域内的各类建设项目和其他物体满足净空限制要求,保障航空器飞行安全的重要工作.针对传统机场净空管理工作中人工计算易出错、数据获取不及时、信息化程度不高等现状,通过分析民用机场飞行区技术标准以及机场实际净空要求,建立机场净空数学模型,并以图形矢量数据、影像栅格数据和数字高程模型等空间地理信息数据为基础,定制开发地理信息系统软件平台,提供基于"一张图"的机场净空管理新模式,实现净空管理保护工作向管理数字化、空间可视化、信息自动化转变,满足大型机场净空管理需求,为民航安全提供有力保障.     

Using Allan variance to improve stochastic modeling for accurate GNSS/INS integrated navigation

MEMS-based integrated system of a global navigation satellite system (GNSS) and an inertial navigation system (INS) has been widely used in various navigation applications. However, such integration encounters some major limitations. On the one hand, the noisy MEMS-based INS undermines the accuracy with time during the frequently occurring GNSS outages caused by signal blockage or attenuation in certain situations such as urban canyon, tunnels, and high trees. On the other hand, the model mismatch between actual GNSS error and the assumed one would also degrade the obtained accuracy even with continuous GNSS aiding. To improve the overall performance for GNSS/MEMS-INS, better error models can be obtained using Allan variance (AV) analysis technique for modeling inertial sensor errors instead of the commonly recommended auto-regressive processes, and on the other hand, the measurement update in Kalman filter is improved using innovation filtering and AV calculation. The performance of each method and the combined algorithm is evaluated by a field test with either differential GNSS (DGNSS) or single-point positioning (SPP) as external aid. In addition to the considerable navigation enhancement brought by each method, the experimental results show the combined algorithm accomplishes overall accuracy improvements by about 18% (position), 8% (velocity), and 38% (attitude) for integration with DGNSS, and by about 15% (position), 75% (velocity), and 77% (attitude) for that with SPP, compared with corresponding traditional counterparts.     

Delaunay三角化中特征约束细分嵌入算法

在Delaunay三角化中,以在特征约束上插入附加点的方式对特征约束细分,可使剖分网格在表达特征约束的同时仍满足Delaunay三角网格特性.本文提出了一种改进的细分嵌入算法--端点外接圆法(ETCM),该算法具有线性时间复杂度.以剖分结果的稳定性、附加点个数、运算耗时和网格质量为评价标准,对ETCM和现有的细分嵌入算法进行了评估.实验结果表明,在运算耗时方面,ETCM受数据分布的影响最小,且耗时最少;在其他方面,与现有算法的最好表现持平.