Incoming Threats: Time-Sensitive Information

Our military faces many challenges. Risk is heightened when traveling through enemy territory, with treacherous terrain and unknown dangers, not to mention the risk of attack by a sudden incoming RPG traveling at 295 meters per second.

Your first thought for dealing with such threats may not involve audio video bridging (AVB), which IEEE initially defined as a standard to guarantee time-sensitive audio and video traffic over Ethernet-based networks. However, Artis, LLC (Advanced Real Time Information Systems) saw an opportunity to leverage the reliability of the standards in guaranteeing delivery of time-sensitive data. They realized they could build a countermeasure solution that could identify the incoming threat, analyze, and respond — all before the RPG reaches the target.

The Iron Curtain project, which started as part of the military’s DARPA program in 2004, takes advantage of the deterministic, low-latency qualities of AVB / TSN (time sensitive networking) standards. The resulting system consists of a lightweight platform around the top of the vehicle, made from modular pieces called APS “legos,” which can match the size of the vehicle, and provides 360-degree coverage. The detection occurs through a distributed optical sensor and C-band radar that can track and profile an incoming threat as it approaches. At that point, AVB technologies kick into gear.

Trophy APS with audio video bridging
Iron Curtain System in the flesh: Trophy APS

AVB/TSN in Action

The sensors capture the speed, relative location to the vehicle, and other critical details of the threat. Meanwhile, the AVB/TSN standards help ensure precise delivery, coordination, and processing of every packet of data over a standard Ethernet network:

  • The AVB core ensures Quality of Service (QoS) by setting aside 75% bandwidth on any given connection for time critical data. The extra bandwidth guarantees that important data gets to/from a destination on time.
  • The system uses a master clock to timestamp each packet of data to keep the sensors, radar, and proper armed countermeasure precisely synchronized. As a result, the AVB core can coordinate what needs to happen, and make sure it happens at the exact right moment.
  • Field Programmable Gate Arrays (FPGAs) carry the crucial burden of multitasking everything that needs to happen all at once. FPGAs use parallel processing to handle all the data and calculations to stay in tune with incoming threats as they travel, adjusting, as well as processing multiple threats coming from a full 360 degree coverage area. If two rockets and a grenade launcher come at you at the same time, the system can see all those packets of information with a precision to handle them all simultaneously.

Precision Response

Once the Iron Curtain system determines the exact moment just before impact, it will direct the countermeasure to fire straight down (or straight up) with the RPG only inches away from the vehicle. Typical countermeasures take them down several meters away, often detonating them in the process. But Iron Curtain actually deflagrates the RPG (with accuracy of up to 1 centimeter), turning it into an instant “dud” that bounces off the side of the vehicle. This precision response helps reduce risk of collateral damage to civilians or dismounted troops.

The Army has recently moved into governmental characterization phase to integrate the Iron Curtain system on Strykers. You can see a fully integrated Stryker vehicles with operational Iron Curtain at the Aberdeen Proving Ground, Maryland or at Redstone Arsenal in Huntsville, Alabama (but only if you happen to have the proper clearance). Or, save yourself the trouble, and watch time-sensitive networking in action with the Iron Curtain system.


Crane, David, August 30, 2009, “Artis Iron Curtain Active Protection System (APS): Shoot-Down Ballistic Reactive Ground Vehicle Defense System”

Osborn, Kris, June 7, 2016, Scout Warrior “Army Tanks Stop RPGs, Anti-Tank Missiles” on

Judson, Jen, October 9, 2017, “‘Iron Curtain’ ready to bring active protection to Stryker,” at