Leica GS18 T expands sites where GNSS can be used

In 2019, BM Field Co., Ltd., a surveying company in Hokkaido, Japan, added the GNSS RTK rover, Leica GS18 T, into their surveying toolkit and has used it on a wide variety of sites since. This has included irrigation canals, wilderness areas and even a landslide site. Working on these sites is easier because the GS18 T measures accurately with a tilted pole, eliminating levelling work requiring high concentration and extra time. The GS18 T has improved work efficiency, reduced costs and enabled GNSS surveys under more challenging conditions.

Virtual reference station surveying boosted by GNSS

BM Field由Tomokazu Aoyama领导，总部位于日本萨波罗（Sapporo），是一家私人测量公司，在挑战性条件下完成调查而闻名。他们的客户正在建立和测量与北海道地区政府机构合作的公司。

"We've been involved in many agricultural surveys to gain an understanding of field areas and create land improvement plans. We’ve also conducted disaster prevention surveys to understand landslides and create recovery plans. And so we’ve gained a reputation as an experienced company capable of handling work in forests and on steep and rocky hillsides,” says Aoyama.

Surveying in challenging conditions

BM Field uses Leica Geosystems equipment to help make this challenging work possible. Even before he set up his own business in 2008, Aoyama was using Leica Geosystems’ products.

“Compared to other surveying instruments on the market, they were the most durable ones in their class. Since then, I’ve continued to use Leica Geosystems’ products because of their robustness and reliability. Even now, our instruments get wet in the rain all the time, but the Leica Geosystems’ products just shrug it off,” he says with a smile.

Aoyama在2015年购买了Leica Viva GS08 Plus，作为该公司的第一个GNSS系统。GS08 Plus接收来自多个卫星源的信号，包括GLONASS和GPS，并且很少被树枝或公用极线阻止信号。

Before this purchase, the company did some GPS-based VRS and RTK surveys but had difficulties depending on location and time of day to get reception from the relevant type of satellite. Thinking that multiple satellite systems would expand the range of sites where surveying could be applied, Aoyama invested in a new GNSS system.

“On introduction, the impact was immediate,” he says. “It has greatly improved our on-site work efficiency.”

Tilt measurements eliminate 250 ladder ascents in an irrigation survey

At a 2019 trade show, Aoyama was introduced to theLeica GS18 TGNSS RTK罗孚。“T”GS18 T代表倾斜,referring to its tilt compensation.

“After hearing that it can measure accurately even with a tilted pole, without calibration, and that it is immune to magnetic disturbances, I strongly felt that this is what we needed,” says Aoyama. “And I was just about to work on the perfect project for it.”

The project was the survey of an agricultural irrigation canal with a height of more than 1 metre.

Without the GS18 T, surveyors would have needed to climb down into the canal and level the pole for each measurement. Since they couldn’t walk at the bottom of the irrigation canal, measuring the next point would mean climbing up the ladder with the GNSS system and then back down again to the next position.

5公里长的灌溉运河以20米的间隔进行了调查 - 重复此方法，他们将不得不上下爬上250次，这将非常艰难。

“当我尝试GS18 T时，我留下了深刻的印象。它可以使用倾斜的杆进行测量，因此无需爬上运河墙，也无需担心气泡。另外，在开始工作之前，无需进行麻烦的校准。因此，我们能够在惊人的短时间内完成现场工作，但结果相同。” Aoyama解释说。

The company has taken measurements in locations that defeated conventional equipment, such as places where visibility is limited and in large areas of wilderness. Aoyama feels that with the addition of Galileo, the analytical capabilities of the system have clearly improved.

Aoyama继续将Leica Geosystems GNSS Technologies添加到其公司的测量工具箱中。在2020年，BM Field获得了Leica Viva GS16GNSS smart antenna and have now a system that makes RTK surveying possible with a small number of personnel.

Aoyama explains, “VRS can't be used in the field if there is no internet connection, but with RTK, you don't have to worry about the internet connection. If the GS16 is installed in a location with a good view to the sky and used as a base station, you can carry the GS18 T into thick undergrowth and still conduct a good survey using real-time corrections.”

Another advantage of RTK is that it can save on communication costs. Currently, the company is using RTK for 80 to 90% of its GNSS survey projects.

"By combining VRS and RTK, we've significantly expanded the range of applications for GNSS antennas," says Aoyama.

Surveying overgrown wilderness and other challenging sites

让我们看一下GS18 T增强BM Field的测量功能的另外两个示例。

In the first project, BM Field was responsible for plotting slope details of a field to create a construction plan for under-field drainage.

"The site was a large agricultural field. I walked across it taking measurements at 20-metre intervals, and because there were no trees or utility poles to block the signal, the capabilities of GNSS were immediately apparent,” says Aoyama.

第二个项目是预防灾难调查。在建造固定围栏以提供加固并防止滑坡之前，有必要了解该区域的当前状况。在灾难恢复的测量中，必须澄清要维护的正常区域与已崩溃的区域之间的边界。因此，GS18 T的倾斜补偿非常有用。

“On a steep slope about 15 metres high, there were many long piles from the old earth retaining fences, but the upper ones were ageing and had tilted diagonally. The underfoot conditions were so bad that if I couldn't measure with the tilted instrument, the job would have been impossible,” says Aoyama.

Measuring using a high pole (left) and a screen of the field software Leica Captivate (right)

Expanding survey and post-survey possibilities with GNSS

Currently, for topographic surveys (including route surveys), Aoyama prioritises the GS18 T and uses the Total Station in locations where the GNSS doesn’t fit the need.

“It all depends on the situation on the site. For example, in the case of the cedar forest in Aoyama prefecture, there were tall trees close together and we couldn’t use GNSS. So, for that project, I created some reference points and then measured these using the Total Station,” explains Aoyama.

However, Aoyama recommends GNSS in locations where visibility is poor, locations where detours must be made and locations where it is inconvenient to bring in heavy equipment.

Aoyama建议：“对于说GNSS不能因为树木而无法使用的人，我建议他们尝试RTK。”“当然，如果该站点需要毫米精度，我将选择一个总站，但是如果精确度为1-2厘米就足够了，我会毫不犹豫地选择GNSS。”

Post-survey office work is also straightforward with GNSS.

The GS18 T and controller at the survey site utilise the 3D field softwareLeica Captivatein theLeica CS20controller. After returning from the field,Leica Infinityoffice software is used to import the measurement data into a PC. Then, a plan view and vertical/horizontal cross-sectional views are created on a surveying CAD system.

“当您使用迷人的现场时，这很方便，因为您不断地意识到杆的准确位置和倾斜度，” Aoyama反映。“由于太阳标记和颜色显示功能，屏幕上的3D查看器也很容易阅读。”

Aoyama particularly likes the navigation function that indicates the next stakeout point on the screen with an arrow. Walking in the indicated direction brings you easily to the measurement point. This function is visually and intuitively easy to use and is especially helpful when moving crosswise.

此外,无穷了data analysis and saved time from potential rework for BM Field.

“Infinity offers a higher degree of freedom and adaptability than software by other companies," says Aoyama. “For example, you can change the detailed settings between elevation/descent, use/do not use satellite signals, and so on. This means there is scope for some trial and error in the analysis of the data. In fact, thanks to this flexibility, there have been several occasions where we avoided having to redo site measurements.”

Faster on-site work and cost reductions boost competitiveness

Introducing the GS18 T has brought BM Field several benefits, expanding the range of sites where GNSS can be used and increasing on-site work efficiency

As the GS18 T can be combined with the GS16 to perform RTK, it is now possible to conduct GNSS surveys at sites with adverse conditions, including lack of internet connectivity. Additionally, data can be received from a broader range of positioning satellites. This, together with the improvement of data analysis, has enhanced the capabilities.

By using GNSS extensively, BM Field has also increased the range of sites where measurements can be taken with a very small number of personnel, leading to a reduction in costs. Similarly, since it is no longer necessary to keep the pole vertical, far fewer person-hours are required for on-site work.

一个计划视图由测量10公顷荒地

“In the product introduction of the GS18 T, it says 'work productivity is increased by 20%. But the increase is much higher than that. As an example, a project which would otherwise have taken 30 days before was completed in 10 days, we are now able to do double or triple the work,” says Aoyama.

This has also brought an increase the profits and differentiates BM Field from its competitors.

BM Field is well regarded by its customers for efficiently implementing both VRS and RTK and their knowledge of implementing GNSS in difficult conditions. This has increased work orders from nationwide construction consultancies in Aomori, Iwate and other areas outside Hokkaido.

As his next move, Aoyama is considering the GNSS receiving antennaLeica GS18 I, which uses Visual Positioning technology.

“I'm always hoping that I'll be able to do more GNSS surveying in adverse conditions that I currently have to give up on. One solution would be the capability to use images to measure point coordinates,” says Aoyama with optimism.

Aoyama对Leica Geosystems GNSS测量技术的未来发展的期望很高，包括BM Field使用这些技术来掌握新的测量挑战的潜力。