Oman Launches New Geodetic Datum

今天GNSS广泛用于阿曼。GNSS定位的高和均匀质量需要连接到国际地面参考框架的地理分比基准，其中参数定期修改。作者描述了在ITRF2008附加的新阿曼国家大地测量基准的创建。

By Yaqoob Al-Toobi and Saleem Al-Hashmi, Oman

基于国家的基于网络的实时运动GNSS服务为多个用户采集和使用地理数据提供了单一标准。Aman旨在建立一个连续操作参考站（CORS）的网络，该网络为广泛的用户提供了广泛的用户，包括测量师，GIS专业人士，工程师，科学家和大众。国际地面参考框架（ITRF）是最准确的所有参考系统，越来越多地被国家使用的国家参考系统的基础。由于板构造和潮汐变形，ITRF的参数定期需要升级。因此，国家地区数量数据也需要定期修订。阿曼使用的基于ITRF89的基于1994年，但它于1994年创建，但它已更新为ITRF2008 EPOCH 2013.这一新的地理中心数据被称为阿曼国家地理机理数据（ongd14），于2013年12月在阿曼地理空间博览会上推出在Muscat，现在为GNSS用户提供现代测量基础设施。

National Survey Authority of Oman

The National Survey Authority (NSA) of Oman, established 1984, is responsible for all survey activities for assembling and maintaining Oman’s geographic archives. NSA creates and enforces standards for topographic surveys and mapping; manages and maintains the national archive of geographic materials; revises and provides maps, air charts and other geoinformation; and establishes and maintains horizontal and vertical control points. NSA has technical and HR capabilities for the production of geodata and performance of the mandated survey activities. NSA employs about 180 technical staff.

History of Datums in Oman

最古老的基准面的Fahud大地基准面是1954 which was established for the oil industry. It is based on the Clarke 1880 reference ellipsoid and is a horizontal (2D) datum. The first geocentric datum was created through a Doppler satellite campaign in 1979, which connected 42 Fahud Datum points to WGS72. To migrate this system into the geocentric coordinate system of ITRF89, seven Doppler stations were remeasured in 1993 and connected to the Cooperative International GPS Network (CIGNET) through an adjustment to the Fundamental Station Wettzell located in Germany (Figure 1). The coordinates of the Fundamental Station Wettzell were referenced to ITRF92 and the solution was transformed into ITRF89. The First Order GPS Network, consisting of 79 GPS control stations, was connected to ITRF89, which adopts WGS84 reference ellipsoid. The Second Order GPS network was gradually established and completed in 2010, resulting in 494 stations. The coordinates were determined by 2-to-4-hour sessions of GPS observations, depending on the length of the baseline.

From ITRF89 to ITRF2008

五个现场团队在2013年1月26日至2013年3月26日，使用Trimble 5700 GPS接收器的20个NSA站进行了59天的GPS观察。该站包括七个主要和13个一阶GPS站（图2）。使用五个GPS接收器，每个站都被占用了7至23天。20站在阿曼附近连接到近50个IGS站，并且通过调节，ONGD14连接到ITRF2008帧2013，称为IGB08。为了确定IGB08关于IGB08的网络的准确性，对2013年2月24日固定的IGS坐标的比较分别为北方，东延和高度组件的3.9mm，5.5mm和8.3mm。在水平部件中，具有自由网络调节的IGB08的NSA站的准确性为5.9mm至8.4mm，高度为12.6mm。所有车站的多次重复性分别具有2.0mm，2.9mm和4.3mm的RMSE，分别用于北方，东延和高度组件。要将新的地理折叠基数据坐标转换为较旧的地区数量数据，反之亦然，因此派生了ITRF2008期间与ITRF89之间的关系（表1）。

结束言论

Survey instruments and GIS software from vendors such as Leica, Trimble, Topcon, Intergraph and ESRI are widely used in Oman. Users of ONGD14 would benefit tremendously when vendors would include the transformation parameters to the new datum in their products.

Biographies of the Authors

yaqoob al-toobi毕业于1985年，毕业于英国Cranwell（RAF），在1985年在贝鲁特大学学习地理，持有各种MSC，最近在国防部，乔丹，自2012年以来一直是阿曼国家调查机构负责人。

Email: nsaom@omantel.net.om

Saleem Al-Hashmistudied business administration at Bradford University, UK, where he received a BA (Hons) in 1994. He is director of geospatial information with the National Survey Authority of Oman.

Email: nsaomprd@omantel.net.om