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Identifying Drone Friend or Foe. More Important Than Ever

Updated: Apr 18, 2022


By: Dawn M.K. Zoldi (Colonel, USAF Ret.)

Russia has invaded Ukraine. This latest move exemplifies the wide spectrum of global security threats, including authoritarian states’ military forces equipped with advanced technological capabilities, that the United States (U.S.), its partners and allies face. Updated strategies, rekindled state-level collaborations and new technologies will chart the course for how current and future conflicts will be waged…and won. Now, more than ever, identifying one’s friends, and foes, in the field will play a decisive role in outcomes.


Charting a Course for Interoperability

Even before Russia started building up its troop presence on the Ukrainian border in 2021, it had been ramping up cyber attacks and GPS-jamming there for years. Russia also incorporated uncrewed aircraft systems (UAS), including “drone swarms,” into their operational model. To both deter and defend when necessary, global partnerships that rely on integrated tech have increasingly played a key role in global security.


In the U.S., in March 2021, U.S. President Biden unveiled an Interim National Security Strategy (INSS) to address these unprecedented challenges by, among other things, modernizing military capabilities by moving towards “cutting-edge technologies and capabilities that will determine our military and national security advantage in the future.”


On the heels of the INSS, Secretary of Defense (SecDef) Lloyd Austin also issued a memo outlining his top three priorities for the Department. It requires innovating and modernizing the DOD “at a speed and scale that matches a dynamic threat landscape.”


In response, the Joint Staff has called for funding for Joint All Domain Command and Control (JADC2). The unclassified JADC2 strategy incorporates a new command and control (C2) network and related lines of effort (LOEs). Ally and partner integration will play a key role.


When it comes to UAS, the DOD will fulfill these priorities through Autonomous and Remotely Crewed Systems (ARCS), according to Christopher O’Donnell, Acting Principal Deputy Assistant Secretary of Defense or Acquisition (DASD(A)) at an April ‘21 AUVSI Unmanned Defense event. The military departments are pursuing these capabilities jointly, while also focusing on their unique mission sets.


The Navy, for example, published its Unmanned Campaign Framework in mid-March 2021 with the vision of incorporating “unmanned systems as a trusted and sustainable part of the Naval force structure…in support of the future maritime mission,” which includes distributed maritime operations (DMO) and littoral operations in contested environments (LOCE). The Navy seeks common manned/unmanned C2 and cross-cutting uncrewed platforms.


The Army’s focus remains on future tactical unmanned aircraft systems (FTUAS) and Short Range Reconnaissance (SRR). The ongoing FTUAS effort focuses on leveraging commercial-off-the-shelf UAS tech for soldier use on the battlefield by FY23. For SRR, the Service continues to collaborate with industry and the Defense Innovation Unit (DIU) to grow the Blue UAS program bench of available trusted non-foreign UAS.


The Air Force’s (AF) Next Generation (Next-Gen) Multi-Role UAS Family-of-Systems (FoS) effort includes complementing the MQ-9 Reaper program (funded by Congress over AF objections) by seeking UAS platforms that will address operations in contested environments through High-Value Airborne Asset Protection (HVAAP) and battlespace awareness, incorporating JACD2 integration and increased autonomy.


All the military departments share common concerns about the threats that small UAS pose to their missions, and those of our allies. In referring to UAS tech, DASD O’Donnell mused, “If we have it, they have it.”


And, yes, when it comes to UAS, they all have it.


UAS In Europe

As the DOD moves to modernize its UAS capabilities, NATO has been seeking similar advantages. UAS play a large role in NATO’s deterrence and assurance. In February 2021, NATO announced the initial operating capability of a new fleet of five long-range UAS, modified Northrop Grumman RQ-4D Global Hawks. These were in addition to UAS owned by the 30 NATO member states including France and Spain. Italy, Belgium, Germany and the Netherlands were all next in line for state-owned armed UAS fleets as well. The UK, France, Holland, Italy, Belgium and Spain all use the MQ-9 for Medium Altitude Long Endurance (MALE) efforts.


Ukraine is neither a NATO member or partner, but like almost every other state actor, it has a UAS fleet. Ukrainian-owned UAS (Turkish Bayraktar TB2 drones) appear to have played a decisive role during the opening days of the Russian incursion, and continue to do so. Business Insider reported that at least one strike “appeared to tear apart a column of Russian tanks and armored vehicles.”


Of course, the Russians have UAS too. Targeting Ukraine’s drone fleet was an early priority in the Russian offensive.


When the skies are cluttered with drones from both sides of a conflict, telling friend from foe becomes difficult. This is especially the case when everyone has UAS fleets, and none of them have Identify Friend or Foe (IFF) transponders.


What is Military IFF?

Military IFF radar-based identification systems positively distinguish friendly aircraft from those of the enemy using spread-spectrum transmissions with secure data encryption. These systems consist of an airborne transponder and a ground or airborne interrogator. They measure the distance and heading to the aircraft, while the transponder encodes identification and position information into the response.

It’s like the childhood game “Marco-Polo”. The interrogator says “Marco” and IFF-equipped aircraft answer “Polo”. But everything is encrypted, so only friendly players can hear the question and provide the right answer. Sagetech Avionics CEO, Tom Furey, breaks it down in easy-to-understand language.

Modes 1, 2, 3/C, and 5 are the military transponder interrogation modes. They consist of standard formats of pulsed sequences from an interrogator, usually found in fighter or AWACS aircraft, surface-to-air missile radar systems, or shipboard air combat control centers. Responding aircraft broadcast their identification, position, altitude and velocity to the interrogator. Both systems share an encryption algorithm and frequently-changing encryption keys to ensure only friendly assets recognize and respond to interrogations.


This is how the friendlies talk and squawk to each other. IFF does not identify hostile targets, just the friendly ones. Rather, it enables troops to discriminate across the full spectrum of UAS by positively identifying friendly ones that are equipped with similar airborne transponders and a ground or airborne interrogator. And being able to sort out the friendlies is a huge step towards making the right decisions that can ultimately save lives.


Knowing Who’s On Your Team

Until recently, IFF has only been used in large aircraft, due to the size, weight and power (SWaP) of the transponders. Sagetech Avionics’ MX12B micro Mode 5 IFF transponder changed that.


The MX12B was the first to be certified to the 17-1000 Mark XIIB level. The smallest and lightest-yet military-grade transponder, it weighs a mere 190g or one-third of a pound. Compared to the next lightest similarly capable transponder, it is six times lighter and 93 percent smaller while delivering all of the required IFF functionality. The MX12B also includes extra features, such as ADS-B In that tracks up to 400 cooperative targets simultaneously and displays them for the remote pilot in the command and control GUI.



In addition to delivering IFF functionality, the MX12B is the only transponder that also includes:

  • ADS-B In that tracks up to 400 cooperative targets simultaneously and displays them for the remote pilot in the command and control graphical user interface

  • Military Modes 1, 2, 3/C, and 5 – these are the transponder interrogation modes, standard formats of pulsed sequences from an interrogating SSR or similar Automatic Dependent Surveillance-Broadcast (ADS-B) system. Modes 1 to 5 are for military use

  • Civil Modes A, C, and S functionality – these are for civilian use

  • ADS-B Out – allows equipped aircraft and ground vehicles to broadcast their identification, position, altitude and velocity to other aircraft and air traffic control

  • Mode 5 response prioritization

  • Antenna diversity for full aircraft visibility from above and below

  • Compatibility with an external crypto computer such as the KIV-77 or SIT-2010

  • Full transmit power per AIMS 17-1000

  • Compliance with the robust environmental standards of MIL-STD-461 and MIL-STD-810

The MX12B now enables UAS, as well as crewed aircraft, to be equipped with a Mode 5 IFF transponder certified to newest, most stringent standards to broaden the scope of battlespace awareness. For the anticipated future changes to the MKXIIB standard, the unit is upgradeable to Level 2B. Mode 5 Level 2B is an encrypted broadcast and passive receiver capability similar to civilian ADS-B. This future capability is in final development now, and will allow NATO and allied aircraft to recognize each other as friendly without requiring heavy and expensive interrogators. It also allows passive ground receivers to maintain battlefield airspace situational awareness, providing accurate, real-time decision-making information to our warfighters.


Fighting Side by Side…Without Blue on Blue

NATO STANAG 4193 directs that all military aircraft update to IFF Mode 5, which requires stronger encryption, different transmitter response prioritization and GPS information about target aircraft locations than Mode 4, the Vietnam-era IFF mode which was retired in 2020.

As the U.S. military and NATO both posture to rapidly innovate and field relevant technologies to fight and win, side-by-side with international partners in a potentially highly contested and hyper-technological fight with a peer competitor, knowing who is on one’s side will remain the highest priority.


In the face of Russian aggression, it is a strategic imperative to ensure every NATO and allied aircraft – crewed and uncrewed – can identify itself as a friend to increasingly automated air defenses. Before, this was not possible for smaller UAS, but thanks to companies like Sagetech nearly every NATO UAS can have encrypted Mode 5 IFF. Planning, programming, budgeting and executing on the right tech to accelerate this critical technological enabler must rank high on the joint and coalition priority list.


About Dawn Zoldi

Dawn M.K. Zoldi (Colonel, USAF, Retired) is a licensed attorney with 28 years of combined active duty military and federal civil service to the Department of the Air Force. She is an internationally recognized expert on unmanned aircraft system law and policy, the Law-Tech Connect™ columnist for Inside Unmanned Systems magazine, a recipient of the Woman to Watch in UAS (Leadership) Award 2019, and the CEO of P3 Tech Consulting LLC. For more information, visit her website at: https://www.p3techconsulting.com.


About Sagetech Avionics

Sagetech Avionics is an aerospace technology company empowering safe flight in crewed and uncrewed aircraft with certifiable situational awareness solutions. Currently serving military and civil duty on most small to medium UAVs, Sagetech solutions are mission-proven and offer decades of program experience, certifications, and millions of flight hours to deliver maximum value over the life of an unmanned platform. Today, Sagetech is expanding its technology platform to create comprehensive, certifiable systems such as detect and avoid solutions. Every day, Sagetech works in concert with its extensive ecosystem of OEM customers, technology partners, and resellers to ensure UAVs fly safer with Sagetech on board. Learn more at sagetech.com.

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