Context: Requirements elicitation is an essential activity to ensure that systems provide the necessary functionality to users, and that they are fit for purpose. In addition to traditional `reductionist' techniques, the use of observations and ethnography-style techniques have been proposed to identify requirements. Research Problem: One frequently heard issue with observational techniques is that they are costly to use, as developers would lose considerable time to partake, and also depend on luck in identifying requirements. Very few experience reports exist to evaluate observational techniques in practice. Results: In this experience report, we draw on several data sources, covering insights from both developers and users. The data were collected through 9 interviews with users and developers, and over 80 hours of observation of prospective users in the maritime domain. We capture `knowns' and `unknowns' from both developers and users, and highlight the importance of observational studies. Contribution: While observational techniques are costly to use, we conclude that essential information is uncovered, which is key for developers to understand system users and their concerns.

翻译：• 研究问题:经常听到的一个与观测技术有关的问题是,这些技术的使用成本很高,因为开发商将花费相当多的时间来参与,而且还取决于在确定要求方面的运气;很少有经验报告可用于评价实际中的观测技术。结果:在本经验报告中,我们利用了若干数据来源,包括开发商和用户的见解。这些数据是通过与用户和开发商的9次访谈以及海洋领域未来用户的80多小时观察而收集的。我们从开发商和用户那里捕捉到的“已知”和“未知”数据,并强调观测研究的重要性。贡献:观测技术的使用成本很高,但我们的结论是,基本信息是发现出来的,而开发商了解系统用户及其关切的关键。