August 28, 2020

A conversation with Mike Glasgow, co-chair of ASTM International UTM Interoperability Working Group

Wing UTM Architecture and Technical Standards lead talks ASTM International standards

As a UTM Technical Standards and System Architect, Mike Glasgow is part of a worldwide community promoting the idea of an open and competitive UTM ecosystem. He is the co-chair of the ASTM International working group WK63418 that is developing a standard for UTM interoperability, and was the network lead for the ASTM International working group WK65041 that developed the Standard Specification for Remote ID and Tracking, published in January 2020. Both of these working groups are part of ASTM’s Committee F38 on Unmanned Aircraft Systems. Prior to joining Wing, Mike spent 35 years developing ATC and related systems for the FAA and international ANSPs. He was the chief system architect for the FAA’s oceanic ATC system (known as ATOP) and for the modernization of the FAA’s Automated Flight Service Stations (AFSS).

Wing is an active contributor to a variety of emerging UAS standards including detect and avoid and others. We believe that standards development is the only way for many industry service providers in any given region to be interoperable and work in concert to support the diverse systems and operations of unmanned aviation.

Q: Can you talk about the scope of the UTM interoperability standard?

A: The working group is taking a crawl, walk, run approach with the standard starting with a base set of capabilities focused on strategic coordination and handling of airspace constraints. We will layer in more complex capabilities over time, such as handling of priority flights, integration of manned flights, and negotiating airspace access between USS providers which is a facilitator of fairness.

The ASTM standard is being developed in the context of a UTM ecosystem that includes a number of UAS Service Suppliers (USSs) that provide services to operators. With different USS supporting different operators, it is necessary for the USS to talk to each other in order to have a complete picture of the airspace. For example, operational intent information would be shared when operations are in close proximity to each other.

"A key focus of the standard is interoperability - defining the protocols used by USS to exchange information."

In the first version of the standard, strategic coordination involves conflict detection and conformance monitoring. Conflict detection compares operational intents (where drones intend to fly) and informs the operator when conflicts exist. This allows an operational intent to be adjusted until conflicts are resolved. Operational intents in the same area of a new operation are obtained from the owning USS via the interoperability protocols. Conformance monitoring checks ongoing position reports received from a drone against its operational intent to make sure it is flying where it is supposed to, and coordinates with other affected USSs when it does not. Airspace constraints let USSs know about things that affect the airspace, such as the landing zone for an emergency medical services helicopter.

The current draft of the UTM interoperability standard is already being used in research efforts that will help refine it over time. These include the FAA’s UTM Pilot Project 2 (UPP2) as well as NASA’s Advanced Air Mobility trials, sometimes referred to as Urban Air Mobility (UAM).

Q: Do you envision multiple USS (UAS Service Suppliers) to be operating in the same city? Or is each city only operated by one USS?

A: The work in the ASTM standards area is focused on an ecosystem of multiple USS operating in the same area. Interoperability is a key focus. If we have multiple drone operators in the same area, we obviously need a complete picture of the airspace so they can plan flights safely.

"Ultimately the ASTM standard allows for multiple USS, but it does not and cannot mandate that there are multiple. That’s a decision that a regulator would make."

But most of the industry supports the notion that multiple USS in the same area is better and highly desirable because it’s very difficult for one provider to optimize for all the different aircraft and types of operations out there. So, by having multiple USS, we can have some that specialize in one particular type of operation and serve those drone operators really well, while still coexisting safely with all of the other operators in the air.

Q: When it comes to UTM, how equitable is the use of shared airspace and how are right-of-way uses being metered or charged?

A: This is one of the most discussed, debated, and philosophized topics in UTM. The reality is that we just don’t have enough data to make these decisions yet. In the first version of the ASTM standard, we are focused on writing requirements that allow us to collect data that we need to understand the nature of inequity in the airspace. This data will allow us to solve for equity.

One of the challenges is that we don’t really have experience with aircraft operating at volume in the UTM ecosystem environment. What we tend to have is experience with how aircraft operate in the traditional manned aviation world where we are all taking off from the same airports and flying the same routes. The solutions from that experience don’t really translate well to the UTM ecosystem. So we are very deliberately focused on not trying to specify that in the first version of the ASTM standard. We’ll collect the data we need to better understand the issue, and then devise appropriate solutions.

USSs already talk back and forth to each other when they are trying to plan a flight. As a first step, in the case where a conflict-free route can’t be found, in the next iteration of the standard we are considering a very simple form of negotiation where basically a USS could simply ask another USS to adjust an operation to accommodate another one. Good citizens in the ecosystem may accommodate those types of requests as much as possible. There is motivation to do this because the potential alternative is a very heavy-handed approach to managing equity. This simple form of negotiation will be an initial first step. What happens beyond that will really be data-driven.

Q: What information about a flight must be exchanged in real time between USS?

A: We’ve focused on two main areas in the standards so far - Remote ID and UTM Interoperability.

In the remote ID standard, we define two methods of sharing of remote ID information.

  1. For Broadcast remote ID: Electronic equipment on the aircraft is broadcasting a radio signal. The signal can be picked up locally, and encoded in it is ‘my location’ and ‘who I am.’

  2. For Network remote ID: The standard takes advantage of the fact that most drones will be in continuous contact with the USS for the duration of the flight. Over that connection, we have the ability to provide the location and identification information, which can be accessed across the Internet by anybody who needs to see it. Because this data is shared via the Internet, it’s not constrained by transmission distance.

The ASTM remote ID standard defines all of the data that must be shared, and includes things like location in x, y, and z (latitude, longitude, altitude) as well as time, characterization of the error on that data and several other fields.

In the case of UTM, we’re mostly focused on pre-flight activities in the first version of the standard; making sure that two drone flight paths don’t intersect with each other at the same time and place. Because this is a strategic deconfliction process that occurs prior to a flight, position reports used for tactical deconfliction are not helpful. Instead, USS share their “operational intents” over the network. Basically, they’re telling everyone where the flight is going to be and when, with some error bounds enclosing it. It’s necessary that all USS have complete and current information about other operations in the area, so we have mechanisms defined in the standard to ensure that is the case. Essentially, if I am a USS planning a flight, I have to prove that I am aware of all of the other operations in the area so that we can have confidence that they were properly avoided.

Constraints are similar. Constraints are a concept where you can have a volume of airspace that represents some information: it could be a no-fly area, an area with degraded cellular coverage, or a variety of things. A USS with regulatory approval would provide a service to create the constraint, and then the USS would also have to share that information with the other USS so that it can be factored into their flight planning.

Q: How will ASTM International standards be set up to ensure that as many people as possible participate in UTM, especially non-commercial drone flyers?

A: With the ASTM standards, we are very focused on identifying how something can be done, but not specifying what should be done. It is that classic separation of standards and regulation.

So, you asked how we will set up standards to ensure participation, but generally, it’s not one of our objectives. It’s a policy decision whether or not to require participation. The one thing we can do in the standard is to try to give our regulators tools that will encourage participation, and keep it simple for participants.

"With the ASTM standards, we are very focused on identifying how something can be done, but not specifying what should be done. It is that classic separation of standards and regulation."

For example, in the ASTM remote ID standard, one of the capabilities that we included is support for “non-equipped network participants.” That refers to the model airplane community, a very large base of aircraft that are not equipped to broadcast or communicate in real time with the USS to participate in network remote ID. And so the standard defined a mechanism that a regulator could choose to use, whereby a hobby model airplane flyer can manually report their operation before they fly. That information would be distributed through network remote ID, giving the hobbyist a simple way to participate with a low barrier.

We try to be thoughtful in the ASTM standards with things like that, but we definitely try to stay away from policy issues. The same notion applies when you are talking about setting up airspace and what density of operations are allowed. We generally don’t get into those types of policy issues.

Q: How can we learn from other countries that have successfully implemented UTM already?

A: Unfortunately, ASTM is sometimes thought of as an American organization. It is not. It is ASTM International. In our working groups for Remote ID and UTM, we strive to include stakeholders from around the world. We have participants from Japan, Australia, Europe. When we had our working sessions (before COVID-19), we moved them from country to country to ensure participation from a diverse cross-section outside of the United States. In addition, input to the whole standards-making process includes not just the FAA’s UTM Conops, but we are looking at a variety of conops from around the world. And we’re making sure we’re staying abreast of other standards activities that are going on.

"So, it is a primary objective of the ASTM International working group to be just that; international in nature."

There are a couple motivations for that: one is that we would prefer to avoid redundant activities, so we try to coordinate regularly with other standards development organizations such ISO, EUROCAE, ASD-STAN, and RTCA. The Global UTM Association (GUTMA) is another good venue for coordinating international efforts.

An example of avoiding redundant efforts is that EUROCAE has produced a standard on geozones, so we aren’t pursuing that in ASTM and instead will leverage and/or be in sync with that effort.

Another key motivation for international coordination goes back to the desire for global harmonization. Conflicting standards can hinder that objective.

An important organization for international cooperation is ICAO. ASTM has a good working relationship with ICAO and we were happy last year when, at Drone Enable, they gave a pretty resounding endorsement of the ASTM remote ID standard as a global standard.

Q: And when you say the first generation of the ASTM International standard, how does that compare with UTM 2.0 and where are we in that discussion? Do we have a 2.0 standard yet, or are we pointing in that direction?

A: The standard is not tied to any particular ops concept. So, yes the FAA’s UTM Concept of Operations version 2.0 version is out, but the EU is also developing their U-Space concept of operations and several individual countries have also developed their own. They are all considered as part of the process. Because we are not aligning with any particular ConOps, our version numbers are independent.

In our crawl, walk, run approach, V1 is targeted for this year. It is primarily focused on conflict detection and dealing with constraints, and it is focused on the interoperability between USS to accomplish those functions.

"We expect to have that first UTM interoperability standard out this year, and we expect that to be the basis for a lot of research that we will build on."

The next version of the standard, which will start looking at things like priority of flights and simple negotiation, will be targeted toward the end of this year or sometime early next year. We will keep iterating and addressing more complex issues as we go and bring in the research that is done using the earlier versions of the standard.

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