Reference Station user strategies in a tectonic environment

Author:Penny Boviatsou

地震是对构造板之间运动的反应。随着两个板以稳定的速度一起推动，沿板边界的岩石变得越来越压力，直到最终必须给出东西为止 - 地震沿着板边界区域的某个地方发生。

新西兰位于澳大利亚和太平洋构造板的边缘。澳大利亚和太平洋板沿着弯曲的边界相互推动，通常不会平稳地越过彼此。他们以一系列小的快速运动移动，每次都伴随着地震。

SmartFix, based on the world’s largest reference station network, HxGN SmartNet, is New Zealand’s most extensive GNSS reference station network with more than 70 stations nationwide. SmartFix delivers centimetre level, real-time kinematic corrections, post processing solutions and sub-metre GIS corrections. HxGN SmartNet is an integrated 24/7 GNSS network RTK and correction service, built on the world’s largest reference network, enabling GNSS-capable devices to quickly determine precise positions.

“Providing a real-time kinematic (RTK) correction service over the internet and RINEX files for post processing, our customers can enjoy the benefits of SmartFix,” said Bruce Robinson, director at Global Survey Limited. “If their GPS or GNSS receiver can connect to the internet, SmartFix can deliver the data they need.”

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Earthquakes shaking up New Zealand

新西兰有两种类型的地震。北岛下方的深层地震形成了一个定义明确的乐队（地震区），从马尔伯勒（Marlborough）穿过怀特岛（White Island）。浅层地震往往发生在这个地震带的东南部，而较深的地震发生在西北。

新西兰Geonet是地震委员会（EQC），GNS科学和新西兰土地信息之间的合作伙伴关系，监视该国所有地质危害，每天将50至80次地震定位，每年约20,000。地震可以在新西兰任何时候发生。

These earthquakes are continually altering the shape of New Zealand and while a lot of the movement is small and unfelt, it is continual and the result is perceivable, measurable and locally variable. The measurable and variable part is what the reference station network SmartFix needs to deal with.

有许多快速运动结合了横向运动和垂直运动的例子。这种运动显然不统一；这种可变性为需要建立可靠的调查控制或运行参考站网络的人带来挑战。

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Investigating earthquake activity

尽管在澳大利亚和太平洋构造板块的影响下，新西兰在不断地移动和变形，但该国的数据旨在为功能提供不断变化的坐标。

基准定义了与物理位置有关的坐标，纵向和纬度或高度。预测是代表基准位置的不同方式，例如，如地形图上使用的北ing和往东。他们一起定义了新西兰的坐标系。

To manage this deformation, the datum itself is moving and deforming along with the New Zealand land mass – it is a “plate-fixed” datum.

The New Zealand datum is known as NZGD2000, and this datum is based on International Terrestrial Reference Frame (ITRF) 1996 as at the position on the feature on January 1, 2000. Because the datum is deforming, NZGD2000 coordinates no longer reflect the true positions of points relative to one another.

The local area distortion, however, is small, and for most applications, the deformation can be and is ignored. This allow for distances, bearings and areas to be calculated directly from NZGD2000 coordinates. This deformation, however, needs to be continually addressed and managed by the reference station administrators.

igno的误差ring the variation is no more than one millimetre in a kilometre for each year since 2000. A deformation model is periodically applied to account for deformation due to earthquakes, regarding calculating NZGD2000 coordinates, and as the measurement of the deformation model becomes more accurate.

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Challenges when running a reference station in New Zealand

NZGD2000基准设置为2000年1月1日 - 最后一次一切都很好地融合在一起。自2000年以来，新西兰已经进行了17。5年的差异运动，尽管商标的坐标没有改变，但相对位置却有。今天从三个不同参考站进行调查的观点可能会有三个不同的NZGD2000坐标取决于所使用的参考站。

“Education of clients is a major part of SmartFix administrator job here in New Zealand, as we are upskilling users to understand the geodetic implications of station selection,” said Robinson.

第二个挑战是获取和选择two coordinates for the reference stations that the Leica GNSS Spider reference station software requires. The two coordinates being the current epoch coordinates to ensure the reliability of the network and the NZGD2000 coordinate. The GNSS Spider solution is an integrated software suite for centrally controlling and operating GNSS reference stations and networks and helping to manage complex environments such as New Zealand.

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A reliable and efficient solution

Using a network like HxGN SmartNet (SmartFix in New Zealand) saves field crews time as it precludes the setup of separate base stations, and it avoids the risk of having control fail due to a damaged or stolen base and removes the issues of radio interference. Surveyors have long used GNSS networks to save time and money as well as remove potential sources of error.

Instead of carrying around:

• GPS接收器
• 电池和电缆
• 两个收音机
• a tripod and a pole
• and setting up their own local base for each project,

网络用户只需携带带有内部调制解调器或外部手机的GPS或GNSS智能天线（Rover），然后使用该设备快速访问永久参考站网络。这些永久电台的组合数据用于生成RTK校正，并在比传统无线电解决方案更大的距离下提供准确的定位。

“At Survey Global we are committed to the growth of the SmartFix (SmartNet) network,” said Robinson. “It enables our customers to get reliable and repeatable NZGD2000 coordinates, despite the tectonic challenges, and for the user it makes them more efficient, allowing them to complete projects on time and on budget.”