Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Autonomy Levels for Unmanned Systems (ALFUS) FrameworkVolume II: Framework Models Initial Version



Hui-Min Huang, Elena R. Messina


This document describes the current Framework models of the overall Autonomy Levels for Unmanned Systems Framework, or ALFUS. ALFUS addresses the autonomy issues along the lifecycle of the unmanned system (UMS), particularly, the autonomy issues at the lifecycle stages of requirements specification, testing and evaluation, and performance measures. ALFUS also augments additional UMS major concerns including safety and risk. ALFUS contains a Metric Model that is composed of metrics along the three established axes or aspects. ALFUS is generic and applicable to multiple UMS domains. This document also discusses how ALFUS might be applied to selected domains that include military, homeland security, and manufacturing. Ongoing issues and future directions are also addressed.
Special Publication (NIST SP) - 1011-II-1.0
Report Number


automony, contextual autonomous capability (CAC), environment, human independence (HI), human robot interaction (HRI)


Huang, H. and Messina, E. (2007), Autonomy Levels for Unmanned Systems (ALFUS) FrameworkVolume II: Framework Models Initial Version, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed June 15, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created December 28, 2007, Updated November 10, 2018