Detect moving objectives with flirtatious airborne radars (those in which both radars are separated) has long been a nightmare due to the echo generated by the reflexes of the earth, the sea or the buildings. But that could be changed thanks to an innovation of the Chinese army.
As twin platforms move independently, The echoes are dispersed throughout the distance (a phenomenon known as rank migration), blurring the energy signal energy.
Doppler frequencies too They are widely dispersed, saturating the objectives with noise. Worse, the echo behaves unpredictably at different distances, challenging traditional suppression methods.
A study, Posted in Journal of Radarsled by Li Zhongyu, from the University of Electronic Science and Technology of China in Chengdu, shows a “two-channel noise cancellation method with space-temporal decoupling that It allowed to detect three moving vehicles with a clarity never seen. This is the story.
Two modest Cessna-208 Caravan aircraft flew in formation, separated by hundreds of meters of altitude. One emitted radar signals; The other, flying at a lesser height, remained completely silent, capturing echoes.
In the distance, three vehicles moved quickly through wavy terrain, dense in vegetation and scattered structures: A scene designed to hide moving objectives in a background noise storm. Radar screens only showed a noise similar to snow, since traditional filtering methods had difficulties. Then, there was a technological miracle.
As soon as the new technology was activated, the screen was deleted without the slightest noise signal, as the images of the article show. Using a system known as Keystone transformed and high order compensation, The LI team concentrated the scattered energy of the objective in unique distance cells, improving the detectability with a method known as movement correction. They also used another technique known as spectrum compression, which controls Doppler frequency dispersion to refine the radar vision.
Next, innovation arrives: space-time decoupling, a novelty Method that uses a matrix derived from the decomposition in singular values to mathematically unravel the non -linear knots of the echo. By aligning spatial frequencies to zero, while preserving relative speed profiles, the perfect cancellation of environmental interference between double channel echoes was allowed.
The implications of this, after the first tests carried out, could transcend science. Military aircraft equipped with this radar technology could penetrate clouds, day or nightscanning large areas to locate vehicles, ships or missiles in motion, without emitting detectable signals. In addition, a radar system of this type is much more difficult to interfere.
“According to our knowledge, this is a worldwide first,” says Li, awarded the National Invention Award In defense technology and appointed by the Chinese government as one of the most important “future radar stars.”
In recent Air fighting between India and Pakistanit was reported that Indian combat planes were victims of invisible attackers. After analyzing the radio conversations of the Indian pilots intercepted by the Pakistani Air Force, some Chinese military experts believe that the low interception probability radar (LPI), combined with other electronic war technologies, could allow Chinese manufacturing airplanes and missiles to attack first without prior notice.
LPI radars reduce the risk of detection by decreasing power or modifying frequenciesbut still lead to exposure risk. The LI system could eliminate that risk.
During the evidence, the silent Cessna detected terrestrial objectives with clarity greater than 20 decibels, compared to existing methods. In simulations with marine interference (towed, chaotic and notoriously difficult to suppress), he achieved An effective detection with ultrabaja signal-signal relationships, where their rivals failed.
His method did not use any artificial intelligence, something that requires large computer resources. If it works in a Cessna, you should work on almost any plane.