In 2029, the US state of California will see the opening of the first high-speed rail system in the country. The project, commissioned by the California High-Speed Rail Authority, will connect San Francisco and the Los Angeles basin - the state’s so-called ‘mega-regions’ - allowing customers travelling the route to reach their destination in under three hours with speeds exceeding 200 miles (322km) per hour.
（这个故事是通过Sensefly带给您的）
加州交通工程公司杰帕特erson & Associates (JLP, now Jacobs Engineering Group) was enlisted by the authority in early 2015 to perform the engineering design work for the Los Angeles to Anaheim corridor. The challenge facing former vice president at JLP, Marc Cañas, and his colleagues, however, was that no surveying data existed for this route prior to the project’s inception. This meant that, before work could commence, it was necessary to survey the entire area: a 30 mile (48km) long by 1,500 feet (457m) wide active railroad corridor, which sees up to 100 trains a day pass through it.
Choosing the right tools
有了一个重要的绘制领域和紧密的时间表，对于JLP的团队来说，收集他们需要，快速，快速和最小的日常操作中的数据来收集所需的数据至关重要。在早期阶段考虑了传统的测量选择，例如通过载人飞行和地面测量进行的空中映射；但是，这些无法满足严格的时间或灵活性要求。基于地面的测量技术需要冗长的许可才能访问该站点，并且由于训练流量而导致的持续破坏。另外，虽然该地区的载航空飞行将避免造成干扰的必要性，但收集和处理数据可能需要八到十周的时间。该团队还需要更深入的三维数据模型，以最好地为项目物流提供信息并指导决策，从而得出结论，即无人驾驶飞机（UAV）技术将是最好的解决方案。
Having previously used senseFly eBee drones on small-scale projects, Cañas and his colleagues opted to use the senseFly eBee RTK, a survey-grade mapping drone. Designed to capture both aerial photography and mapping data, the eBee RTK can create highly accurate 3D models in real time and was chosen for its professional, survey-grade quality and portability. Using this technology, the team could be on site and flying within a matter of minutes, without the need for complicated launching systems or disruption to rail processes and operations. The software’s geofencing feature, available via the pre-installed eMotion software, was also an important factor in the decision, as it helps to enhance the safety of the vehicle during flight by enabling flight planning in advance.
克服障碍
尽管熟悉无人机技术，但JLP在大规模测量中对无人机技术的经验有限。此外，严格的联邦航空管理局（FAA）法规意味着，尽管JLP在进行该项目时拥有了两个EBEE RTK，但该团队只能一次驾驶一架飞机来收集数据。结果是，在项目的早期阶段，需要大量的反复试验才能确定任何可能干扰数据收集的因素，并使团队能够尽可能地将软件无缝地集成到工作流程中操作。
Based on these trials, JLP then created a series of 1,500 foot (457m) by 5,200 foot (1,585m) flight polygon areas with overlapping areas of approximately 300 feet (91m), which formed the basis for ground control points (GCPs). While GCPs are not typically required with an RTK drone, the nature of the project environment meant that the RTK network was unreliable and ran the risk of dropping out in certain areas. As well as helping to refine the execution of their missions, the initial trials also showed that the chosen approach would fit JLP’s corridor objective and optimise time out in the field.
JLP的团队还必须考虑FAA法规对最高海拔水平提出的挑战，这表明无人机飞行高度不能超过起飞高度（ATO）以上400英尺（122m）。为了克服这一点并获得高质量的正交空中图像，JLP使用情感软件设置了每个像素地面分辨率的3.6厘米（1.4英寸）。情感程序还用于合并高程数据，这有助于确保所有航班都保持在地面上方相同的高度并提供一致，可靠的数据。
Perhaps the biggest challenge of all for JLP, however, was that the area surrounding the Californian rail corridor was heavily urbanised, which meant that the team’s initial ground planning did not always transfer well in practice. For instance, when identifying take-off and landing sites, what looked like a suitable location in the office was often, in reality, obstructed by overhead wires or street lights, or even by buildings that were not yet visible on the satellite imagery. It was, as a result, necessary to adapt to the environment, and the final GCPs were painted in the surrounding streets approximately two weeks before the commencement of the project.
在正确的轨道上
完成所有82 GCP的最终确定，JLP的团队能够为数据收集过程的开始铺平道路。绘制30英里的走廊 - 面积为61平方英里（158公里2)—JLP deployed three of its staff to the site to fly a total of 41 flights. With an average flight time of 28 minutes and average flight altitude of 200 feet (61m), 11,800 images were captured. These were downloaded and processed in a matter of hours by three other members of the JLP team using Pix4Dmapper Pro software – all in the comfort of the JLP office.
通过使用Sensefly Ebee RTK，JLP能够在不到一个月的时间内将洛杉矶的高度准确，专业的测量数据汇集到加利福尼亚高速铁路的阿纳海姆走廊 - 这项工作将超过18个以上几周使用传统的测量技术，如果使用载人飞机，则花费两倍。该团队以每个像素为1.5英寸（3.8厘米）的正截止图像，即使是最载人的航空产品的分辨率两倍，并且能够达到垂直和水平的一到两英寸（2.5至5厘米）的准确性。
Marc Cañas, former vice president of National Freight Rail at JL Paterson & Associates (JLP, now Jacobs Engineering Group):
“自从加利福尼亚高速铁路制图项目完成以来，JLP将其Sensefly Ebee RTKS投入了另外15个项目，包括施工监测和工程。这些操作从早期阶段获得大量深入，准确的数据而受益匪浅 - 在某些情况下，有助于证明项目的财务可行性。”
“很明显，无人机技术有可能改变使用和收集测量数据的方式，并且可以成为彻底改变业务运营和工作流程的效率和有效性的绝佳工具。尽管该项目是我自己和我的团队的学习曲线，但我们的初始投资在财务投资回报率和员工的培训时间方面都值得多次。”
