[According to a July 1 report by Defence Blog] In July 2026, the U.S. Army officially signed a long-term contract worth 3 billion US dollars, entrusting Lockheed Martin with the continuous mass production of the AN/MPQ-64F1 Sentinel A4 ground-based air defense radar. Valid until 2031, the contract marks the system as the core pillar of the U.S. military's airspace awareness over the next five years. As the ultimate evolved variant of the Sentinel series, the A4 fully replaces traditional mechanical scanning structures with an Active Electronically Scanned Array (AESA) antenna, enabling microsecond-level beam agility and parallel tracking of multiple targets. For the first time among tactical radars, it achieves high-probability detection and precise classification of low, slow, small unmanned aerial vehicles, loitering munitions and swarm targets, effectively filling the performance gap of the original generation system when confronting FPV attack drones costing only hundreds of US dollars.
  Operating in the X-band (8-12GHz), the system can be fully deployed on a single trailer within just 15 minutes. It boasts a detection range of 75 kilometers against fighter jets and delivers stable tracking of small UAV targets. Its data can be seamlessly integrated into Patriot missile batteries, Avenger close-in weapon systems and the U.S. Marine Corps MADIS architecture, providing critical target guidance for kinetic interception and electronic countermeasures. Unlike previous passive defense solutions relying on a single sensor, the Sentinel A4 adopts dynamic waveform adaptation and low-RCS target recognition algorithms to form a closed-loop response chain of "detect-to-lock, lock-to-guide". This allows the U.S. military to achieve active perception, real-time data distribution and coordinated interception of drone threats for the first time in complex electromagnetic environments.