Work Item
ASTM WK75923

New Specification for Positioning Assurance, Navigation, and Time Synchronization for Unmanned Aircraft Systems

1. Scope

This standard will be part of a suite of standards focused on approximately twenty essential functions for a standards-based approach to widespread and routine BLOS operations. The concept for this approach is detailed in the Technical Report being developed by the ASTM AC478 committee on BLOS Strategy & Roadmapping. The Standard Specification must define Positioning Assurance and define minimum requirements for the UAS to know where it is positioned (and potentially localized) and the error associated with that position. The Standard Specification must also define Navigation and define minimum requirements for UAS navigation. The Standard Specification must define Time Synchronization and define minimum requirements for the UAS to know that the time value that its systems are using is assured and trusted. While none of these essential functions are completely unique to BLOS operations, from a safety standpoint they become more critical for BVLOS/BLOS operations. Many VLOS operations also require these for mission success, but not necessarily for assurance of safety. As such, proper definition and scoping will also provide benefits to many VLOS missions. Finally, this will be the first brand new standard stemming from the efforts of AC478 and will serve to validate that that framework can be implemented successfully in the form of a standard. Special Considerations: The following topics are in scope for the Working Group, in priority order: Definition of Positioning Assurance, Navigation, and Time Synchronization. Establishment of Performance Measure(s) for these functions, including units of measurement (if applicable) and error measures. Establishment of Level of Service measures to provide a means to compare performance measure(s) to the required performance per specification for actual operations. Establishment of Tolerable Latency measures to provide a means to establish that the latency of the function is sufficient to deliver the required performance per specification for actual operations. Note that it is possible (but not required) this may be combined with Level of Service. Define how a manufacturer or operator must establish and make this information available to support the transparency needed for safe BLOS operations. Define any requirements for general airworthiness and instructions for continued airworthiness (ICA) pertinent to these essential functions. The following topics are out of scope for the Working Group: Definition of min or max limits for performance, level of service, or latency measures unless minimum performance, as defined, is already long-established and accepted in industry. Definition of a set of graduated performance bounds may be acceptable for the purpose of allowing performance classifications. Prescription or assumption of reliance on particular implementation technologies or approaches. The standard must strive to be technology/solution agnostic. Test methods for determination of performance. These may be standardized at a future time.


positioning; time synchronization; navigation; BLOS; BVLOS; UAS; unmanned systems


This standard is needed to meet the growing demand for known positioning, navigation, and time synchronization performance for UAS integration into the airspace. It will help to enable safe interoperability of manned and unmanned aircraft.

The title and scope are in draft form and are under development within this ASTM Committee.


Developed by Subcommittee: F38.02

Committee: F38

Staff Manager: Mary Mikolajewski

Work Item Status

Date Initiated: 02-15-2021

Technical Contact: Adam Morrison

Item: 001

Ballot: F38.02 (22-01)

Status: Will Reballot Item

Item: 001

Ballot: F38 (22-05)

Status: Negative Votes Need Resolution