基于全球定位系统的相机标定方法研究

采用标定模板进行相机标定是目前广泛应用的方法。由于标定模板的限制,该方法在大视场、远距离工作时不能覆盖所需画面的全部,不能实现对相机的准确标定。结合全球定位系统实时动态(GPS RTK)定位工作模式的高精度全方位坐标信息获取技术,提出一种基于GPS的相机标定方法。该方法基于GPS RTK工作模式获取GPS质心在WGS-84坐标系中的坐标信息,通过坐标转换得到世界坐标系中的坐标位置;用被标相机拍摄GPS在不同位置的图像,采用Harris角点检测算法获得GPS质心的图像坐标,根据成像模型及相机投影矩阵,实现相机标定。实验证明,该方法可有效获取全方位的空间坐标信息,与传统相机标定方法相比,图像像素标定均方误差仅为0.125 36,是一种行之有效可取代标定模板的相机标定方法。

基于多变量LSTM的GPS坐标时间序列预测模型

针对全球定位系统(GPS)坐标时间序列预测中存在精度不足的问题,提出一种基于多变量长短时记忆(LSTM)的GPS坐标时间序列预测模型。利用灰色关联度方法对同一地区不同观测站的GPS坐标时间序列数据进行关联度分析,找出与待预测数据(佘山站U向历史数据)关联度较强的数据。将待预测数据和与之关联度较强的其它数据作为多变量预测模型的输入,利用LSTM能够将现有的输入信息与历史输入信息相结合的特性,建立多变量LSTM模型。通过与ARIMA、单变量LSTM模型预测结果比较,证明该方法有更好的预测效果。

基于TGO的坐标转换方法探讨

随着GPS技术在众多领域的广泛应用,坐标转换成为测量工作人员经常要解决的问题。由Trimble公司研发的主流GPS数据处理软件TGO1.63具有强大的功能,然而测量工作人员平时主要应用其基线解算和网平差功能,而对TGO的某些坐标转换拓展功能应用较少甚至并未涉及。详细探讨了如何利用TGO实现坐标转换,包括同一椭球的坐标转换、不同椭球的坐标转换以及地方坐标系间的转换,并付诸工程算例。

An Automatic Cycle-Slip Processing Method and Its Precision Analysis

On the basis of analyzing and researching the current algorithms of cycle-slip detection and correction, a new method of cycle-slip detection and correction is put forward in this paper, that is, a reasonable cycle-slip detection condition and algorithm with corresponding program COMPRE (COMpass PRE-processing) to detect and correct cycle-slip automatically, compared with GIPSY and GAMIT software, for example, it is proved that this method is effective and credible to cycle-slip detection and correction in GPS data pre-processing.

Localization of Small Mobile Robot by Low-Cost GPS Receiver

This article deals with a problem of the robot localization in the outdoor environment by using the GPS （global positioning system） data. In order to navigate the robot, it is necessary to transform the global position into the local map in the form of two-dimensional Cartesian coordinate system. The transformation is based on the model of the Earth-WGS 84 reference ellipsoid. The aim of this article is to experimentally evaluate a set of low-cost GPS receivers applicable as position sensors for small outdoor mobile robots. The evaluation is based on series of measurements executed in different times and places. The measured data is processed by given procedure and acquired positions are transformed into the local coordinate system. Accordingly the accuracy of the measured positions is statistically evaluated. The evaluation of used GPS receivers is done by comparison with data acquired by high-end geodetic GPS system Leica 1200, which is used as a reference GPS system.

Comparison between Google Earth KML Data and RTK Data on a Flight Planning Simulated to the Unmanned Aerial Vehicle Microdrone MD4-1000

The UAVs （unmanned aerial vehicles） and the use of graphical data files of extension KML （keyhole markup language） have become popular nowadays. The KML files are associated to the Google Earth applications. Developed by Microdrone company for planning, overflight simulation and data flight analysis, the program mdCockpit was used in this experiment. The UAV Microdrone＇s flight path was programmed in two ways： using geo referenced images from Google Earth and entering points coordinates into the program. These points have had their geographical decimal coordinates collected by GPS （global positioning system） （RTK （real time kinematic）） method. The aim here is to describe a way of evaluating the difference between the alternatives of flight planning. A flight path, defined a route with 22 points, was also simulated in the program mdCockpit. The points were collected and saved, while the images captured by the program went automatically forming a georeferenced mosaic. A comparison between the differences of coordinates to each point was made by choosing on the images and also by a RTK positioning. The result was up to 14.20 m to a 100 m flight height. There is a significant change of position and this can result in unwanted over flights in locations or even jeopardizing the safety of air activity.

噪声模型的建立对速度及其不确定度的影响分析

针对现有全球定位系统时间序列研究中不同时间序列跨度内噪声模型的建立对速度及其不确定度的影响方面研究较少,选取ITRF2008框架下中国区域的10个国际GNSS服务组织基准站的坐标时间序列,将每个序列按照时间跨度分为5a、10a、15a和20a四个时段,采用不同的噪声模型组合对它们进行噪声分析,并对结果进行对比。结果表明,在各时间序列跨度内,噪声模型的建立对精化速度场非常重要;随着时间序列长度的增加,速度不确定度比值呈上升趋势。