LE BOURGET, France — Three German companies made their joint debut at the Paris Air Show to present a counter-drone system designed to foil anything from explosive-laden aerial robots to protecting against corporate espionage from the skies.

Rohde & Schwarz, ESG and Diehl Defence inked an agreement earlier this month to further develop the Guardion suite of systems, which already was deployed to guard the 2015 G-7 summit in Elmau, southern Germany, and the 2016 visit of U.S. President Barack Obama in Hannover.

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The system consists of various sensors — radio, radar, acoustic and optical — to detect the presence of drones in the nearby air space. A command and control system, a derivative of the Bundeswehr's own Taranis suite, processes the sensor data and offers situational awareness of any incoming threats through a map-like visualization.

Depending on the drone type, system operators can initiate countermeasures ranging from shutting down the specific frequency band of the threat aircraft's radio link, jamming the GPS signal or, in the case of fully autonomous aircraft operation via inertial navigation, fry the approaching drone's electronics with a high-power electromagnetic pulse.

Goetz Mayser, Rohde and Schwarz's, director of C-UAV detection and counter solutions, said the company is "very active in China" in collecting radiofrequency signatures of commercial unmanned aerial systems. Knowing the specific technology is important for jamming only drone targets during an operation, leaving all other civilian radio communications undisturbed, he said.

Cataloging the characteristics from drone makers Parrot and DJI alone means covering 90 percent of the market, Mayser said during an interview at the company's exhibit here. Guardion clients are supplied with periodic updates to the radio signatures database, a process resembling the subscription to a computer antivirus application, he explained.

According to Daniela Hildenbrand, ESG's product manager for counter-drone systems, the market is expected to see a significant uptick as the robots become ubiquitous in people's everyday lives.

"It's growing along with the threat scenarios," she said.

Potential clients from countries in Europe and Southeast Asia have expressed interest in the technology, though officials declined to offer specifics.

Engineers are still studying the possibility of offering a fourth method of countermeasures called spoofing. That tactic would allow Guardion operators to send fake navigational signals to incoming drones, effectively taking them over.

But the technology is still a ways from being operationally deployable, said Mayser. Plus, taking control of someone else's drone poses a potentially thorny legal question. "Once you take it over, you're responsible," he said.