Revising the Airspace Model for commercial drone integration
This paper is also containing superior solution exitisng Amazon's patent applications (even if those are also often based on prior art, please contact me to complete a list).
The paper also contains discussion on practical aspects of ground avoidance in US airspace.
Comments
This is Google Drive link to public pdf document, 53 pages. Google generates the link and you cannot control its name. I think the comment above is a part of moon landing denial society smokescreen. So beware,
The link in this post looks like it may be a password phishing scheme, Beware!