Two Views of the Same Sky: PerimeterScope and Automated Flight Following

How a passive, real-time local airspace picture complements the fleet tracking that wildfire aviation already depends on.

Anyone who has worked a fire knows the airspace over an incident is one of the most demanding flying environments there is. Tankers on final, a helicopter turning at a dip site, lead planes and Air Attack overhead, and increasingly drones somewhere in the mix. For more than two decades, Automated Flight Following has been a backbone of how the wildland fire community keeps track of its aircraft in that environment. PerimeterScope is not here to replace it. It answers a different question. Automated Flight Following tells you where your fleet is. PerimeterScope shows you what else is in the air right where you are standing.

What Automated Flight Following does, and does well

Automated Flight Following, or AFF, is an online government application that automatically tracks the location and velocity of specially equipped aircraft and provides that information in near real time to dispatchers, aviation managers, and other authorized users. Each participating aircraft carries a tracking unit that reports its position, speed, altitude, and heading over a satellite link to a central ground based system, where the data is consolidated and displayed on a secure web map. Several thousand personnel across the Forest Service, the Department of the Interior, the FAA, and state cooperators rely on it, and registering an aircraft and its tracking device is a requirement for flying federal aerial firefighting contracts.

The value is real and well proven. AFF gives dispatch and aviation managers a shared, wide area view of the fleet, cuts down on radio traffic and position check ins, and, because it keeps a continuous record of where aircraft are, it takes much of the search out of search and rescue when something goes wrong. It is a safety backbone, and nothing about PerimeterScope changes that.

What it is built to do, and what it is not

It is worth being precise about scope, and the AFF program is precise about it too. By the program’s own description, AFF is a fleet tracking and accountability system, not an airspace deconfliction tool, and the automated picture still depends on a human element to act on it. It tracks the aircraft that are equipped and registered for it. That is exactly its purpose, and it fulfills it.

The design has a direct consequence, though. Three things never appear on an AFF screen. Aircraft that are not enrolled in the program. Aircraft carrying no compatible tracking unit at all. And drones. On top of that, positions arrive as periodic reports over the satellite link rather than as a continuous stream, and seeing the picture depends on a network connection back to the central servers. For managing a known fleet across a region, that is fine. For knowing what is sharing your immediate airspace this second, there is a gap.

What PerimeterScope adds: a real-time local picture

PerimeterScope is a passive, receive only system. Sitting at or near the incident, it listens directly for the signals that aircraft and drones are already putting out: ADS-B on 1090 MHz and UAT on 978 MHz from crewed aircraft, and broadcast Remote ID from drones. It maps them together into one live picture of the airspace immediately around you, refreshed as fast as those signals arrive, which for ADS-B is roughly once per second.

The important part is what it does not require. PerimeterScope does not care whether an aircraft is enrolled in any program or flying any contract. If it is broadcasting, PerimeterScope hears it. That includes the general aviation aircraft that wanders too close to the fire traffic area, and it includes drones, which is the category no fleet tracker can show you. The hazard is not hypothetical. During the 2025 Palisades Fire, a single civilian drone struck a Super Scooper and punched a hole in its wing, grounding the aircraft and briefly halting aerial firefighting over the fire. Because PerimeterScope builds its picture on the ground from the radio energy already in the air, it keeps working in the remote, mountainous country where fires burn and where radar coverage and connectivity are thin.

Honest about the limits

PerimeterScope sees what is broadcasting. A drone flying without Remote ID, or an older aircraft without ADS-B Out, will not show up, and widening that detection is on our roadmap rather than in the system today. Its picture is local by nature, bounded by radio range, so it is not a wide area fleet tracker and it is not a system of record for your contracted aircraft. That is AFF’s job, and AFF does it well. And to be completely clear, PerimeterScope is an awareness tool only. It does not transmit, jam, or interfere with any aircraft or drone. It only listens. The system is in active field testing, including recent work in live wildfire airspace in Utah.

Better together

These are complementary tools, not competing ones. AFF gives aviation managers and dispatch a near real time, wide area view of where the equipped fleet is, with the coordination and search and rescue value that comes with it. PerimeterScope gives the people at the incident a real time, on scene view of everything broadcasting in their immediate airspace, including the traffic and the drones that AFF was never designed to display. Run side by side, you get both halves of the picture at once: the fleet you are managing, and the airspace you are sharing.

	Automated Flight Following	PerimeterScope
What it shows	Aircraft enrolled and equipped for AFF	Anything broadcasting nearby, crewed or drone
How it gets data	Onboard satellite tracking unit to a central server	Passive RF reception on site
Coverage	Wide area, fleet across the region	Local, within radio range
Update cadence	Periodic position reports over satellite	As broadcast, about once per second for ADS-B
Drones	Not shown unless an enrolled asset	Broadcasting Remote ID drones are shown
Primary role	Fleet tracking, dispatch, search and rescue	Real-time local airspace awareness

PerimeterScope also feeds the data it receives, both crewed and drone, exclusively into the ADS-B Exchange global feed, and from there into tools the fire community already uses, such as Watch Duty. The goal behind all of it is the one everyone on a fire shares, which is keeping the airspace safe and everyone going home.

To learn more or discuss field testing, reach us at info@tacticalsignal.solutions or (386) 800-2553.