测量英格兰的最高峰

作者：Staff

英国许多敏锐的登山者都熟悉著名的“三峰” - 苏格兰，威尔士和英格兰的最高山峰：

1. Ben Nevis
2. Snowdon
3. Scafell Pike

In recent times, the summits of Snowdon and Ben Nevis have been re-measured by Ordnance Survey Great Britain (OS) to validate their heights using the latest techniques.

With the 80th anniversary of the triangulation of Great Britain in 2016, the time was right to re-measure the height of the remaining one; Scafell Pike, Cumbria – England’s highest peak.

In early 2016, the re-measurement of Great Britain’s highest peak, Ben Nevis in Scotland revealed with great enthusiasm that Ben Nevis was indeed higher than was previously thought.四舍五入后，公开的高度从1,344万升至1,345万。

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Reaching for the stars

作为ITV系列Countrywise的一部分，该节目进行了军械调查，以帮助主持人本·福格（Ben Fogle）重新衡量Scafell Pike的高度。军械调查转向Leica Geosystems的专业设备和解决方案，以帮助交付这一激动人心的项目。新的自学Leica GS16 GNSS smart receiverwas deemed the best tool for the job.

Scafell Pike’s height published on the Ordnance Survey maps was derived from measurements last taken in the 1937 during the triangulation of Great Britain. The current height is rounded to 978 metres. A re-measuring of the mountain was certainly needed.

这个项目的目的是re-measure山ain using the latest GNSS technology. As well as giving an accurate measurement of the true height of England’s highest peak, the undertaking also validated the previous measurements taken about 79 years ago.

Fogle and outside broadcast team set off on the trail from Wasdale Head to Scafell Pike with a team of surveyors from Ordnance Survey. They carried with them the latest Leica Geosystems GNSS technology, a newly released Leica GS16 smart receiver, Leica CS35 rugged tablet computer and a level and staff. This compact lightweight solution was a far cry from the theodolites carried in the original survey all those years ago.

Due to the challenging remote location of the mountain top and the absence of a mobile phone signal, it was not possible to use Network RTK corrections. Nor was it possible to attain a base and rover RTK solution via radio due to the distance from known points in the valley and obscuring terrain. For the highest level of accuracy, post-processing of a static session would definitively calculate the new height. By using the Leica GS16 receiver, however, it was also possible to calculate the new height to within a few centimetres whilst at the summit of the mountain by using the SmartLink service provided by Leica Geosystems for a quick value.

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什么是SmartLink？

SmartLink是确切的点定位（PPP）服务，使GNSS用户能够achieve real-time centimetre accurate positioning worldwide, ideal when working in remote areas around the globe. SmartLink does not require a local RTK base station or network RTK infrastructure to operate meaning lower capital investments in equipment and the ease of simply visiting the site with a SmartLink compatible receiver is the only requisite.

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How does SmartLink work?

SmartLink基于经过尝试的PPP技术，最初是在1990年代初开发的，用于离岸定位，例如在运营通常遥远的石油和天然气行业中 - 因此远离参考站和通信链接。SmartLink包括一个全球的GNSS参考站网络，通信链接和不同的网络控制中心，所有这些都具有冗余，以保证为关键操作提供服务。

SmartLink corrects or models GNSS error sources such as ionospheric and tropospheric delays and satellite orbits and clocks. Correction signals are then computed and uplinked to a series of seven geostationary satellites and broadcast to the compatible GNSS receiver, such as the Leica GS16 used on Scafell Pike. By delivering GNSS corrections via satellite, the common weakness of network RTK – the mobile phone network - is overcome.

Leica Geosystems’ continual innovation has recently brought the benefits of using SmartLink to the land survey community. A positive side-effect of using如果RTK数据链接被中断，则智能链接特别感兴趣，例如，由于移动网络繁忙或掩盖无线电链接的地形，然后SmartLink无缝地弥合差距以保持不间断的百分点定位eliminating the frustration of downtime awaiting data links to be restored.

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Reaching the peak of performance

At the summit, the Leica GS16 was mounted on the summit trig pillar to observe satellite signals and calculate the height of the trig pillar. The versatility of the Leica GS16 also allowed the raw observations to be recorded for definitive static post-processing back at the office.

The Bernese scientific software was used for this ratification of SmartLink using precise ephemeris data, the OS Net v2009 coordinate reference frame and OSTN15/ OSGM15 transformation and geoid model. Interestingly, and to prove the quality of real-time SmartLink obtained height, the post-processing calculated height differed by only 2-4 cm.

参加探险队的多媒体的OS负责人安迪·斯蒂格尔（Andy Steggall）说：“过去的OS验船师是如此准确，这一点非常准确。这样一项重大的体力就被现在最先进的设备提供的精确精度所取代。但这表明，奉献和承诺使其正确的传统燃烧了。我们确信这个故事将成为引人注目的电视。我们可以透露，根据当前的Geoid模型OSGM15，英格兰最高点计算的新高度为978.072米。”