Aircraft Traffic Density Database: /Data

This dataset is the associated input for the software, traffic-density-database. It is intended to process observed aircraft traffic information into unmitigated collision rates given user specified geographic regions or aircraft tracks. The user may also specify the time of day, month of year, and day of week to be evaluated. Unmitigated collision rates are useful for aircraft safety assessments, and may be combined with the efficacy of mitigations—e.g., air traffic control, detect and avoid, see and avoid—in order to estimate the total operation safety. The input data included with this release has the following attributes. See the README in the Data directory for more detail on the contents of each data file. The data span 8727 observed hours, from 4 November 2018 to 3 November 2019. Note that there are periods where there are no radar data available, so the data span does not correspond directly to the full date range extent. There are over 31.65 million flight hours observed (includes both discrete-code and 1200-code aircraft). The vertical spatial (height) discretization corresponds to standard altitude feature thresholds in the national airspace: 100 feet Above Ground Level (AGL): Cutoff to exclude on-ground traffic 500 feet AGL: nominal lower manned aircraft operating altitude 1200 feet AGL: typical lower altitude for Class E airspace 3000 feet AGL: approximate upper bound for Class D airspace 5000 feet AGL: approximate upper bound for Class C airspace 10,000 feet Mean Sea Level (MSL): typical Class B upper bound, and lower threshold for transponder requirements 18,000 feet MSL: lower bound for Class A Airspace 29,000 feet MSL: Reduced Vertical Separation Minimum (RVSM) lower altitude bound 41,100 feet MLS: RVSM upper altitude bound 60,100 feet MSL: upper bound for Class A Airspace The temporal discretization is 3 hours. The latitude range is 22.83°N to 50.00°N. The longitude range is 127.00°W to 64.83°W. (Note: MATLAB indicates W longitude using negative numbers, e.g., 127.00°W is -127.00.) Two tables with different horizontal spatial discretization are provided: one for all altitudes, where the discretization is 1/6 of a degree in latitude and longitude (corresponding to approximately 10 NM); and one for altitudes below 5000 feet, where the discretization is 1/24 of a degree (approximately 2.5 NM). The table containing all altitudes is the default.

本数据集为traffic-density-database（交通密度数据库）软件的配套输入数据集，旨在根据用户指定的地理区域或航空器航迹，将观测到的航空器交通信息处理为未缓解碰撞率（unmitigated collision rates）。用户还可指定待评估的时段、月份及星期几。未缓解碰撞率可用于航空器安全评估，还可与缓解措施（如空中交通管制、探测与规避、目视规避）的效能相结合，以估算整体运行安全性。
本发布版本附带的输入数据具备以下属性，各数据文件的详细内容请参阅Data目录下的README文档。
本数据集覆盖2018年11月4日至2019年11月3日期间的8727小时观测时长。需注意，部分时段无可用雷达数据，因此数据覆盖时长并不完全等同于上述完整日期范围。本次观测累计飞行时长超过3165万小时，涵盖离散编码与1200编码航空器。
垂直空间（高度）离散化采用美国国家空域系统中的标准高度特征阈值：
- 距地面100英尺（AGL，Above Ground Level，离地高度）：用于排除地面航空器的阈值
- 距地面500英尺AGL：载人航空器的标称最低运行高度
- 距地面1200英尺AGL：E类空域（Class E airspace）的典型下限高度
- 距地面3000英尺AGL：D类空域（Class D airspace）的近似上限高度
- 距地面5000英尺AGL：C类空域（Class C airspace）的近似上限高度
- 平均海平面10000英尺（MSL，Mean Sea Level，平均海平面高度）：B类空域（Class B airspace）的典型上限高度，同时也是应答机（transponder）配备要求的下限阈值
- 平均海平面18000英尺MSL：A类空域（Class A airspace）的下限高度
- 平均海平面29000英尺MSL：缩小垂直间隔（RVSM，Reduced Vertical Separation Minimum）的下限高度
- 平均海平面41100英尺MSL：RVSM的上限高度
- 平均海平面60100英尺MSL：A类空域的上限高度
时间离散化步长为3小时。
纬度范围为22.83°N至50.00°N，经度范围为127.00°W至64.83°W。（注：MATLAB中西经以负数表示，例如127.00°W对应为-127.00）
本次发布提供两张采用不同水平空间离散化方案的数据表：一张覆盖所有高度层，经纬度离散化步长为1/6度（对应约10海里（NM，nautical mile））；另一张仅覆盖5000英尺以下高度层，经纬度离散化步长为1/24度（对应约2.5海里）。默认采用覆盖所有高度层的数据表。