The chronicle of an adventure

Author:Penny Boviatsou

On October 19, 2014 Matteo Miceli, a famous Italian oceanic sailor, left the Port of Riva di Traiano located close to Rome, Italy, with the Italian sailboat ECO40 for the Roma Ocean World Project. His goal was to sail around the world alone, without the help of any fossil fuel or additional supplies, other than what he brought with him for the entire 27,000 nautical miles (50,000 kilometres) journey.

ECO40是40级海洋容器（总长度为12.0米），配备了在板载上记录的Met-ecean参数的数据采集系统（即明显的和真实的风速和风速和风向，大气压，电流压力，电流速度，空气和海温等）以及船本身的运动学特征（即地面的速度和路线）。罗马大学和理工都灵大学的教授团队通过使用三个Leica GR25 GNSS参考接收器记录了该船的动作。有了这些，他们能够：

• Calculate the height of waves along the ECO40 route by using the boat as a buoy and validate the numerical models of the United Kingdom - based Met (meteorology) office;
• Improve the structural design of the Class 40 sailboat by means of calculating the boat’s dynamic stress and boat material durability during the trip;
• 记录波从生态特征40’s movements to produce a polar diagram of the boat’s speed, which would be useful for future Class 40 racing boats.

Miceli transmitted the data via satellite for analysing to Professors Paolo De Girolamo and Mattia Crespi of the University of Roma La Sapienza and to Alessandro Pezzoli of the Polytechnic Turin.

在回到意大利的途中，将三个斗篷和航行25,000海里航行后，Eco40在赤道上盖了。马特奥（Matteo）在巴西海岸附近约600英里。他被一艘货船救了。当他回到意大利时，他组织了一次探险，试图恢复Eco40，这是没有成功的。一个月后，探险队再次尝试，并在巴西海岸发现了Eco40 300英里。现在，该船回到了意大利。

幸运的是，数据与船一起保存，研究人员能够对旅程进行最终分析。

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The sailor’s journey

The planned route was the classic clipper route that runs from west to east through the Southern Ocean, taking advantage of the strong westerly winds. Namely the route consists in passing the Gibraltar Strait, then in descending the Atlantic Ocean and sailing around the Antarctic, at an average latitude of 50° S, from west to east rounding the most famous capes of the world: Cape of Good Hope, Cape Leeuwin and Cape Horn. Finally, sailing the Atlantic Ocean back to the Strait of Gibraltar and come back to the homeport.

“The data collected by the Leica GR25 GNSS receiver and the Leica AS10 antenna concerning the movement of the boat reported that ECO40 sailed wave heights of roughly 6 metres during the first storm with maximum waves reaching 10,0 m,” said Miceli. “After the end of the trip, we are now able to calculate the exact measurements.”

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Gathering the data

卫星调制解调器每天将一部分测量数据发送给土地团队。这些数据是由船只衡量并几乎实时传输的，它极大地帮助了负责Eco40安全的团队；船在航行过程中真正面对的实际天气条件的知识可以改善路线策略并提高船只安全性。

“The measurements of the boat movements, obtained from the three GPS receivers, if properly analysed, can provide a measure of the waves that the ECO40 encountered during the navigation,” said Miceli.

The three high precision Leica Geosystems GPS receivers were placed on the left and right side of the stern along the boat cross axis while the remaining one was placed close to the boat entrance along the boat’s main longitudinal axis. The data were acquired by the system during the navigation of the ECO40 and stored on a flash-card by each receiver. The data analysis was carried out in post-processing after the recovery of the flash-cards.

后处理中采用了两种不同的策略：

1. The “Variometric Approach for Displacements Analysis Standalone Engine” (VADASE)
2. 运动基础运动学方法。

The two methods were used complementary in order to obtain the boat motion, and the boat motion has been applied to estimate the waves’ properties faced by the sailboat during its navigation around the world.

实际上，使用第一种（即变体方法）来计算船只的涌入，浪涌和摇摆动作，而第二个（即移动的基础运动学方法）用于计算滚动，音高和偏航运动。通过使用堆，螺距和滚动运动来得出波的特性（即定向波谱）。

When fast movements have to be detected and their effects suddenly evaluated, Leica VADASE can help researchers make the most informed decisions immediately. The solution adds additional value to traditional GNSS monitoring, providing accurate velocity information based on a stand-alone GNSS receiver that is continually available in real time for precise and reliable analysis of fast movements.

船性能数据(即速度和over ground) can allow, after a certain amount of time that is required, to obtain a statistically meaningful database, to estimate the real polar velocity curves of the boat. Indeed these curves were used for the prediction of the optimal route made by the land team by using a route optimisation software, which was sent daily to Miceli.

船的实际极速曲线与船设计师估计的理论曲线不同。这是由于几个原因，其中起着重要的作用，船员可以将船“将船”推向其性能的最大性能以及在计算曲线本身时通常不考虑的波浪的存在。

These data are used mainly for two technical and scientific purposes:

1. The first purpose is the calibration and/ or verification of the numerical models output that are commonly used for the wind and wave forecast and/or analysis into the oceans, and the calibration of the remote sensing data (e.g. satellite wind and wave measurements).
2. The second purpose is directly related to the vessel design. Indeed the knowledge of both the movements and the loads that this kind of vessel can deal with, together with the response of the materials to the fatigue stresses, can improve significantly the design methods.

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Analysing the measurements

This undertaking was the first time ever that a sailboat’s movement was accurately measured by GNSS on a global journey and data were transmitted via satellite every few hours. In terms of the met-ocean conditions and in terms of the boat heeling, the first violent storm experienced by the ECO40 during its navigation occurred in the Gulf of Lion 21-22 October 2014. The heeling of the boat was estimated by using the GPS signals that were analysed by using a moving base kinematic approach. This analysis allowed to estimate the heeling angle α during the whole storm event.

De Girolamo说：“关于大洋的条件，我们根据船只几乎实时测量和传输的风数据分析了风暴。”

Wind data were measured on board of the ECO40 by means of an anemometer placed on the top of the mast. The first comparison was carried out with the European Centre for Medium-Range Weather Forecasts (ECMWF) and the second one was carried out by using the forecasted data, provided by the numerical model GFS (Global Forecast System).

This comparison, along with the results of the heeling analysis, showed that the wind measurement height plays an important role. The corrected measurements of the wind are comparable with the results obtained from the numerical models: a good agreement is noticeable within the first 60 hours. Nevertheless, a sensible discrepancy between the measured wind data and the numerical one is noticeable as the storm peak occurs.

The direct comparison between the forecast and the measured wind speed showed, in the present case, as expected, relevant discrepancies. These discrepancies are such to underestimate the forecast wind condition in the order of 50 per cent of the forecast wind for severe storm conditions.

The researchers and professors were able to put together a research paper based on the comparison between measured and numerical wind data.

“Still, despite the unexpected end of the journey, the data collected from the Leica GR25 GNSS receiver and the Leica AS10 antenna were enough to provide ocean scientific information for the development of new ocean knowledge and technologies for the benefit of society,” said Frank Pache Senior Product Manager, GNSS Networks and Reference Stations at Leica Geosystems.