Army making noise with radar encryption

Army researchers have come up with a noise-encrypted waveform that will allow radar operators to see without being seen—an increasingly important aspect for units operating in contested electromagnetic environments.

The tunable Advanced Pulse Compression Noise, or APCN, waveform, developed at the Communications-Electronics Research, Development and Engineering Center, will allow soldiers to optimize radar performance whether under electronic warfare attack from an adversary or just operating in a crowded, high-traffic environment, the Army said in a release.

"Encrypting our radar waveforms limits the likelihood for adversaries to intercept and exploit our emissions,” said Dr. Mark Govoni, a research scientist in CERDEC’s Intelligence and Information Warfare Directorate's Radar Division, who established the theory and patented the design for APCN. “Programming the waveform in real-time takes this capability even further, and ensures operational effectiveness."

APCN, which mixes traditional and non-traditional aspects of waveforms, can be programmed in real time to adapt to different situations, and hides itself through continual variations. "Having the ability to transmit a radar waveform that's continually changing, one that never repeats itself, and looks like noise, is extremely difficult to intercept and becomes advantageous for police because they can now remain anonymous to radar detectors," Govoni said.

CEDRDEC said that the APCN waveform could be used by law enforcement and first responders, in addition to the military.

The prospect of operating in contested environments has become a priority for the Defense Department as its focus shifts from the relatively free airwaves of the Middle East to the more congested Asian Pacific and Europe. Officials have noted Russia’s extensive use of electronic warfare in Ukraine and Syria, as well as China’s growing proficiency. And after years of neglecting new advancements in EW, the military services have of late put a renewed effort into developing and acquiring EW technologies.

EW can involve anything from interfering with the operation of unmanned vehicles to disrupting GPS signals to corrupting cell phone communications. For CERDEC’s APCN team, it involved allowing radar to operate smoothly regardless of the situation.

CERDEC worked with the Army Research Laboratory to develop the APCN demonstrator. Down the road, researchers will look to add some autonomy to the system, so that it could dynamically adapt to congested environments rather than being programmed manually.

"The battlespace is continually evolving, and with that, comes the need to change the way we think about radar design,” said Dr. Paul Zablocky, director of CERDEC's Intelligence and Information Warfare Directorate. “Techniques such as real-time re-programmable waveform synthesis and low probability of intercept/low probability of detection (LPI/LPD) provide added capability that will address the emerging electromagnetic spectrum challenges our Soldiers are likely to face in the future."