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The use of small unmanned aerial system (UAS)-based structure-from-motion (SfM; photogrammetry) and LiDAR point clouds has been widely discussed in the remote sensing community. Here, we compared multiple aspects of the SfM and the LiDAR point clouds, collected concurrently in five UAS flights experimental fields of a short crop (snap bean), in order to explore how well the SfM approach performs compared with LiDAR for crop phenotyping. The main methods include calculating the cloud-to-mesh distance (C2M) maps between the preprocessed point clouds, as well as computing a multiscale model-to-model cloud comparison (M3C2) distance maps between the derived digital elevation models (DEMs) and crop height models (CHMs). We also evaluated the crop height and the row width from the CHMs and compared them with field measurements for one of the data sets. Both SfM and LiDAR point clouds achieved an average RMSE of ~0.02 m for crop height and an average RMSE of ~0.05 m for row width. The qualitative and quantitative analyses provided proof that the SfM approach is comparable to LiDAR under the same UAS flight settings. However, its altimetric accuracy largely relied on the number and distribution of the ground control points.
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METAR SMS Text Message Service to Support Part 107 Compliance: A Classroom Lab Exercise
Unmanned aircraft systems (UAS) have been used to support a wide range of industries. Code of Federal Regulations Title 14 Part 107 provides the rules that govern most commercial UAS missions. Section 107.51 of the regulations limits the maximum UAS altitude to 400 feet above the ground or structure and a minimum clearance of 500 feet below clouds. The required cloud clearance is often easy to comply with as most cloud coverage is thousands of feet above the ground and well above the 400-foot ceiling. However, many missions require the UAS to fly nearly low-altitude clouds or early morning fog. In these situations, the pilot must know the altitude of the clouds to maintain the necessary clearance. Accurately estimating cloud height visually is very difficult to do. However, the Federal Aviation Administration (FAA) has partnered with Leidos Flight Services to develop an SMS text service through the 1800wxbrief.com service to receive real-time Meteorological Aerodrome Report (METARs) weather reports in plain text. This paper shows how this new tool can be used to determine cloud height and incorporate it into a classroom activity to support Part 107 compliance.
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- Award ID(s):
- 2000281
- PAR ID:
- 10497400
- Publisher / Repository:
- Zenodo
- Date Published:
- Journal Name:
- Journal of advanced technological education
- Volume:
- 3
- Issue:
- 1
- ISSN:
- 2832-9635
- Subject(s) / Keyword(s):
- Part 107 Unmanned Aircraft system Drones METAR Cloud
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5281/zenodo.8423423
