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CIDAR challenge pushes the limits of passive ranging

Participants made meaningful progress, though the final prize proved elusive

Sept. 25, 2026

DARPA sets ambitious goals by design. The recently concluded Computational Imaging Detection and Ranging (CIDAR) challenge demonstrated where the limits of today’s technology lie and what it will take to move beyond them. 

No team met the performance threshold required to earn a prize in the final round: developing passive imaging algorithms capable of measuring distances out to 10 kilometers with the accuracy and low latency of today’s active ranging systems. However, competitors made impressive progress toward this deliberately difficult objective. 

“CIDAR captures the spirit of DARPA. We take big swings at problems where success is far from guaranteed because that is how we learn what technology can achieve today, and where more work needs to be done,” said Jonathan Hoffman, Ph.D, deputy director of DARPA’s Multi X Office. “In this case, no team cleared the bar we set, but they pushed the boundaries of passive ranging and gave us a much clearer understanding of what works, what doesn’t, and what still needs to be solved. That is valuable progress.”

CIDAR was designed to tackle a fundamental limitation in optical ranging. Active systems such as laser detection and ranging and laser range finders can provide highly accurate distance measurements, but they rely on emitted signals that can reveal the observer’s presence. Passive systems avoid those emissions, but current approaches capture only a fraction of the distance information potentially available in images. CIDAR challenged participants to close that gap using computational imaging, machine learning, and artificial intelligence.

Announced in December 2024, CIDAR progressed through multiple stages. Five small businesses and universities received initial $200,000 prizes, and five teams later earned $50,000 semifinal prizes in January 2026. 

In the final round, competitors analyzed a new set of imagery for the opportunity to earn prizes of $1 million, $600,000, and $400,000. To qualify for a prize, teams had to meet a defined minimum performance threshold across targets at ranges from 2.5 to 10 kilometers. The performance of the Zetascope team came closest to meeting the metrics required to win the challenge. While its submission did not cross the required threshold, the team demonstrated particularly promising progress toward CIDAR’s goals.

Although the finish line proved elusive, CIDAR helped define the technical advances still needed to achieve accurate, low-latency passive ranging at long distances. In doing so, the challenge provided valuable insights and a stronger foundation for future efforts to move the field forward.

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Media with inquiries should contact DARPA Public Affairs.

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CIDAR captures the spirit of DARPA. We take big swings at problems where success is far from guaranteed because that is how we learn what technology can achieve today, and where more work needs to be done

– Jonathan Hoffman, Ph.D, deputy director, Multi X Office

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