High-tech radar to help in fight against relic crimes

A high-tech radar system, commonly used in the aerospace and defense industries, could one day help China protect its cultural relics from criminals, especially tomb raiders.

Researchers in Shaanxi province are exploring the feasibility of using the phased array radar, capable of monitoring and tracking moving targets over a large area, to prevent the theft of outdoor relics.

The radar is not only capable of keeping real-time tabs on targets 24/7, but it can also trigger precise alerts about suspicious people, vehicles or activities to facilitate a more efficient crackdown on relic crimes.

Shaanxi, which is considered an important point of origin for the Chinese civilization, boasts priceless historical and cultural relics that cannot be moved to museums for safekeeping. These include ancient buildings, tombs, cave temples and stone carvings.

The province has 49,058 immovable cultural relics, including 270 important heritage sites under State protection, according to the Shaanxi Provincial Cultural Heritage Administration. The fact that these are scattered widely and sometimes cover large areas makes their protection and management very challenging.

For example, the Qianling Mausoleum, built in AD 684, covers an area of 2.3 million square meters. The site comprises the joint mausoleum of Emperor Gaozong, the third ruler of the Tang Dynasty (618-907), and Empress Wu Zetian, the only female emperor in Chinese history.

Some other groups of relics feature complex landscapes, and patrolling these areas is difficult during rain and snow.

Compared with video surveillance or ground motion monitoring technology previously used to protect these relics, the phased array radar is more flexible and reliable, according to Han Jianwu, deputy director of the Shaanxi Institute for the Preservation of Cultural Heritage.

The radar has stronger ability to prevent interference and is more adaptable to complex environments. Its functioning is not affected by rain, snow or light, and it can help prevent nighttime thefts, said Han, who is in charge of the research project.

"The device can detect vehicles within a range of 10 kilometers and spot people within 5 km, so large-scale monitoring can be achieved at a low cost," he said. "Moreover, it can simultaneously capture and track 128 groups of targets and provide their distance, speed, angle, category and trajectory. All this reduces the chance of missing suspicious activities in the monitored area."

The highly efficient radar can search targets within a range of 10 km and pan 45 degrees left or right within a few seconds, allowing it to quickly detect and report human activity. It can also detect slow-moving individuals within the monitoring zone, with a minimum detection speed of 0.3 meters per second, Han said.

With a compact battery panel and a small storage device, the radar can work 24 hours a day, seven days a week, throughout the year. As it has no mechanical scanning components, it requires zero maintenance when deployed in the field. All these features can help promote the use of the device with grassroots units, he said.

The radar has demonstrated feasibility after multiple experiments, Han said, adding that the research team is conducting more tests to be doubly sure.

"In the future, a phased array radar security system will be able to supplement existing security technologies and deliver proactive, intelligent early warning functions that will further enhance the effectiveness of efforts against cultural relic crimes," he added.

The Shaanxi provincial government has pledged to enhance the protection of relics by adopting new security technologies, and with joint efforts from the police and society.

The number of thefts in key national and provincial cultural relics protection sites have been steadily decreasing, with no such crimes reported in 2020 and 2021, according to a news briefing in May 2022.