Invariant’s Surface-to-Air Kinetic Engagement (STAKE) system–Maybe Something the Coast Guard Needs

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TSUNAMI USV fitted with STAKE (Invariant Technologies picture) The launcher is probably only a little longer than the APKWS guided rocket which is 73.8 in (1.87 m) in length so I would estimate this boat is about 24 feet in length. Textron TSUNAMI® USVs range in length from 21 to 38 feet in length.

The need to have a counter to unmanned air and surface systems has been getting a lot of attention lately. Even the Coast Guard has been questioned about this.

The Coast Guard says they are working on it.

So far the counters I have heard the Coast Guard is deploying seem to be primarily intended to interrupt the control link of small commercial drones. Other than machine guns, I haven’t seen any hard kill systems that can deal with larger UASs and USVs including those that might be autonomous.

Potential targets range from consumer drones with a few ounces of explosives to modified personal watercraft or even general aviation aircraft carrying hundreds of pounds.

Using something like a .50 caliber machine gun in a US port is problematic both in terms of accuracy and in the danger of potential collateral damage.

Below are two press releases from Invariant discussing their APKWS based cUAS system, similar to the Vampire system.

From the moment I first saw APKWS, in 2017, I considered it an almost perfect weapon for the Coast Guard because it is cheap enough for wide distribution; it is accurate enough to minimize the likelihood of collateral damage, it has adequate range so that cutters don’t have to be so close improvised armaments can pick off our weapons operators, it is light enough to fit on even the smallest cutters, training requirements appear minimal, and the warhead is large enough to do serious damage to larger targets particularly if multiple hits are made.

invariant corporation’s stake system successfully demonstrates advanced maritime autonomous capability

Feb 18, 2026

(HUNTSVILLE, Ala.) Invariant Corporation’s Surface-to-Air Kinetic Engagement (STAKE) system has once again demonstrated a significant advancement in autonomous maritime Counter Unmanned Systems (C-UxS) capabilities. Earlier this month, STAKE was integrated onto a Textron Systems’ TSUNAMIR Unmanned Surface Vessel (USV) and performed early integration testing at Lake Guntersville.

This milestone marks a significant step forward in the application of APKWS in the maritime domain. The success of the demonstration highlights the STAKE system’s versatility and performance in a highly dynamic, complex environment as well as Invariant’s C-UxS team’s commitment to advancing autonomous weapons development. STAKE, a modular system, can be integrated onto a variety of vehicles with minimal engineering.

STAKE’s maritime payloads consist of two core subsystems: the Hunter, which houses the sensor and laser designation package responsible for acquiring and tracking targets, and the Killer, the precision engagement platform. Together, as previously shown, the Hunter and Killer subsystems operate seamlessly in the maritime setting, confirming the system’s readiness for shipboard C-UxS mission, no matter the size.

“This successful demonstration represents a significant development and reflects Invariant’s position at the forefront of C-UxS innovation as well as kinetic maritime autonomy,” says President Danny Levis. “We are committed to advancing adaptable, high-performance systems that align with the Department of War’s objective to enhance lethality, especially in the maritime domain”.

The TSUNAMI USV provides advanced battlefield connectivity and mission agility to maritime mission sets while keeping warfighters out of harm’s way. With a MOSA design, the system is adaptable to a variety of mission sets and payload integrations. The TSUNAMI family of USVs benefit from over four decades of Textron Systems’ autonomous technology development and integration.
With this milestone, the STAKE team shows that its technology goes beyond computer models. Invariant is committed to not only supporting the fight where it is today, but advancing technology to be where the fight is going.

For more information about Invariant Corporation, visit www.invariant-corp.com.

The New Rules of Engagement: STAKE, C-UAS Agility, and the Future Fight

Aug 26, 2025

The unmanned threat landscape is advancing at breakneck speed. For James Filley, Program Manager for Invariant’s STAKE system, this shift is about rethinking how we design, deploy, and adapt kinetic solutions to meet a battlefield that changes by the day. 

With a career spanning in explosives, missile defense, and tactical ground systems, James made the deliberate choice to go deep, not wide. “I wanted to zero in on a single domain and become the expert,” he says. That domain? Counter-Unmanned Systems (C-UxS). 

Why STAKE Matters Now 
STAKE was born from the proven success of the Containerized Weapon System-APKWS (CWS-A,) but James sees its mobile platform as a major leap forward. “Every system has a use case,” he explains. “The container is great for fixed sites, but with STAKE, users get expeditionary capability. It goes where the fight is.” 
STAKE System

 

Whether mounted on a Humvee or ship deck, STAKE offers battlefield-ready C-UxS capability at a fraction of the cost and without locking users into rigid architecture. “You can bring your own C2, radar, or vehicle. We’ll integrate with it.” 
That flexibility was on full display during a recent shipboard demonstration, which James describes simply as proof of how modular and adaptable STAKE really is. 
The Threat Has Changed, So Must We 
According to James, today’s unmanned systems barely resemble what we saw eight years ago. “The change is like comparing the original telephone to a smartphone,” he says. “We’re no longer just dealing with off-the-shelf drones. Threat actors are now building custom, low-cost, high-lethality platforms at speed.” 
Those platforms aren’t just harder to counter—they’re cheaper and faster to produce. That’s why James sees cost parity as mission-critical. “How do we continuously defeat $100,000 drones without launching $1 million missiles?” 
It’s a real question with real consequences. “The defense side has always leaned toward exquisite systems,” he adds. “But the offense only needs to be good enough. That dynamic breaks our supply chains if we’re not smart.” 

Agility Over Legacy

For James, the most dangerous assumption in modern defense planning is that yesterday’s acquisition timelines still apply. “We used to develop a system over five years and support it for 20. But when the fight changes daily, our tech has to change daily too.” 

This is where STAKE shines. Its modular design, rapid fielding, and compatibility with cost-effective munitions like APKWS give it a major edge, not just in performance, but in sustainability.  

 “We’re not just building a product,” James says. “We’re building a process that evolves with the fight.”

C-UxS as a Forever Fight 

Unmanned systems are the new norm. From land to sea, in peer and non-peer engagements alike, James sees the domain expanding rapidly. “The future fight is unmanned, and that means C-UxS isn’t going anywhere,” he says. “At Invariant, we’re focused on what warfighters actually need. Not five years from now. Now.” 

 What’s Next for STAKE 

With interest growing across multiple services, James and his team continue to adapt STAKE to meet emerging demands. New capability insertions. Faster integration. Expanded CONOPS. STAKE represents our commitment to delivering battlefield-ready systems that are agile, adaptable, and built for the modern warfighter. 

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