Filippo Biondi is an Italian telecommunications engineer who specializes in synthetic aperture radar (SAR), the satellite imaging technique used for mapping, monitoring and surveillance. He is best known for claims, made with University of Pisa chemist Corrado Malanga, that processed satellite radar data reveal chambers, shafts and corridors inside and far beneath the pyramids of Giza. Egyptologists and radar specialists have rejected those claims, and his place in the UAP field comes from the podcasts and personalities that amplified them rather than from any UFO research of his own.

Biondi's published record includes peer-reviewed work on SAR signal processing, among it papers in IEEE Geoscience and Remote Sensing Letters on detecting ship wakes in radar images and on recovering partially corrupted SAR images, and a 2017 conference paper using radar interferometry to track the destabilization of Iraq's Mosul Dam. His ORCID record lists studies at the University of L'Aquila from 2011 to 2015. At the time of the pyramid work he was a visiting professor at the University of Strathclyde in Scotland, according to Retraction Watch.

In October 2022 Biondi and Malanga published a paper in Remote Sensing arguing that SAR Doppler tomography, drawing on tiny vibrations from background seismic noise, could image a network of rooms and corridors inside the Great Pyramid of Khufu. In March 2025 they and colleagues held a press conference describing eight cylindrical shafts descending more than 600 meters beneath the pyramid of Khafre and a wider complex reaching about two kilometers deep. Those findings were not peer reviewed. Former antiquities minister Zahi Hawass said they had no scientific basis and that the team lacked permission to work at the site, and radar archaeologist Lawrence Conyers called the underground-city idea "a huge exaggeration."

The claims spread through the History Channel and The Joe Rogan Experience, and Jesse Michels interviewed Biondi on American Alchemy in December 2025. In March 2026 Michels hosted a debate between Biondi and Geoffrey Drumm, who argues that the pyramids were chemical plants. Later that month Biondi said he had found evidence of a second sphinx buried beneath the plateau, a discovery Newsweek noted had not been confirmed. In July, posts read remarks by Brandon Fugal, owner of Skinwalker Ranch, as hints that Biondi's satellite method had been or would be applied to the ranch's mesa; researcher Joe Murgia replied that this could test the technique if digging confirmed any findings.

On August 10, 2026, Remote Sensing retracted the 2022 paper after a reader raised concerns, saying its editors had "confirmed serious methodological flaws and statistical errors"; the notice did not allege misconduct, and Biondi and Malanga disagreed with the decision. The team's Khafre Project then said it had submitted technical plans and excavation permit applications to Egypt's Ministry of Tourism and Antiquities, without announcing any approval. Biondi remains a trained radar engineer whose most famous findings have not withstood peer review, and whose Giza claims have become a fixture of the 2026 UAP and ancient-mysteries podcast circuit.