TrajAir: A General Aviation Trajectory Dataset

General Aviation (GA) comprises all civil flights except scheduled passenger airline services. More than 90% of the roughly 220,000 civil aircraft registered in the United States (US) are GA aircraft. In contrast with airline service aircraft which operate with two pilots in a structured higher-altitude operational envelope, GA aircraft are often individually piloted in a more unstructured lower-altitude environment. This low altitude environment is also where a bulk of the next generation of Uncrewed Aerial Vehicles (UAVs) are expected to operate. These UAVs are expected to seamlessly interact with other UAVs and manned air traffic operating in this shared airspace. Nowhere is this manned-manned and potentially unmanned-manned interaction more pronounced than in low-altitude terminal airspace around airports. Low altitudes, multi-agent close-proximity interactions, dynamically changing conditions, and rapid decision making are hallmarks of this type of airspace as compared to en-route airspace where agents are typically well-separated.This dataset contains aircraft trajectories in an untowered terminal airspace collected over 8 months surrounding the Pittsburgh-Butler Regional Airport [ICAO:KBTP], a single runway GA airport, 10 miles North of the city of Pittsburgh, Pennsylvania. The trajectory data is recorded using an on-site setup that includes an ADS-B receiver. The trajectory data provided spans days from 18 Sept 2020 till 23 Apr 2021 and includes a total of 111 days of data discounting downtime, repairs, and bad weather days with no traffic. Data is collected starting at 1:00 AM local time to 11:00 PM local time. The dataset uses an Automatic Dependent Surveillance-Broadcast (ADS-B) receiver placed within the airport premises to capture the trajectory data. The receiver uses both the 1090 MHz and 978 MHz frequencies to listen to these broadcasts. The ADS-B uses satellite navigation to produce accurate location and timestamp for the targets which is recorded on-site using our custom setup. Weather data during the data collection time period is also included for environmental context. The weather data is obtained post-hoc using the METeorological Aerodrome Reports (METAR) strings generated by the Automated Weather Observing System (AWOS) system at KBTP. The raw METAR string is then appended to the raw trajectory data by matching the closest UTC timestamps.We also provide processed data that filters, interpolates and transforms data from a global frame to an airport-centred inertial frame. The inertial frame is centred at one end of the runway with the x-axis along the runway. Trajectories are filtered with aircrafts under 6000 ft MSL and around a 5km radius around the airport origin. We also remove duplicates and interpolate data every second. The proceed files also contain wind-data; a crucial factor in decision-making; separated in components along and perpendicular to the runway direction.<b>More Information and Supplemental Tools</b>Please visit http://theairlab.org/trajair/ for more information.<br>

通用航空（General Aviation, GA）指除定期客运航班服务之外的所有民用飞行活动。美国注册的约22万架民用航空器中，超过90%为通用航空航空器。与需配备两名飞行员、在结构化高空作业空域运行的航班客机不同，通用航空航空器通常由单人驾驶，作业于非结构化程度更高的低空环境。而下一代无人飞行器（Uncrewed Aerial Vehicles, UAVs）的主流运行空域也正是这一低空领域，此类无人飞行器需在共享空域中与其他无人飞行器及载人航空器实现无缝交互。这种载人-载人乃至潜在的无人-载人交互，在机场周边的低空终端空域中表现得最为显著。相较于航路空域中航空器通常间距充足的运行环境，该类空域的典型特征为低空作业、多智能体近距离交互、动态变化的环境条件以及快速决策需求。

本数据集包含采集于美国宾夕法尼亚州匹兹堡市北10英里的单跑道通用航空机场——匹兹堡-巴特勒地区机场（ICAO代码：KBTP）周边无塔台终端空域的航空器航迹数据，采集周期为8个月。航迹数据通过部署于机场场内的自动相关监视广播（Automatic Dependent Surveillance-Broadcast, ADS-B）接收机记录，采集时段为2020年9月18日至2021年4月23日。扣除停机维护、设备维修及无航班运行的恶劣天气时段后，有效数据共计111天，每日采集时间为当地时间凌晨1:00至晚上11:00。

该接收机同时使用1090 MHz与978 MHz频段接收广播信号；自动相关监视广播系统依托卫星导航为目标提供精准位置与时间戳信息，通过我们定制的现场采集设备完成数据记录。数据集还包含采集时段内的气象数据以提供环境背景信息，气象数据事后通过KBTP机场自动气象观测系统（Automated Weather Observing System, AWOS）生成的机场气象报告（METeorological Aerodrome Reports, METAR）字符串获取，并通过匹配最接近的UTC时间戳将原始气象数据附加至原始航迹数据中。

此外，本数据集还提供经过预处理的数据集版本：该版本对原始数据进行了滤波、插值处理，并将坐标从全球坐标系转换为以机场为中心的惯性坐标系。该惯性坐标系以跑道一端为原点，X轴沿跑道方向延伸。预处理过程会过滤掉飞行高度超过6000英尺平均海平面高度（MSL）以及距机场原点5公里半径范围外的航迹，同时移除重复数据，并以1秒为间隔进行插值。预处理文件中还包含风向数据——这是航空器决策的关键影响因素，数据被分解为沿跑道方向与垂直于跑道方向的分量。

更多信息与辅助工具请访问 http://theairlab.org/trajair/ 获取。