or Foe (IFF) modification kit, which consists of a new Ethernet router, enhanced Radar Control Terminal (eRCT), Signal Data Processor (SDP) box, and multiple circuit card assemblies. This will convert existing A1 Improved Sentinel units to A3 Enhanced Sentinel configuration, increasing reliability and fixing identified hardware issues to match the capabilities of the F1 Improved Sentinel. The eRCT enables remote operations and includes a tactical data recorder needed to support counter-battery radar capabilities. A new operational mode, Multi Mode Sentinel, provides detection for Rocket, Artillery, and Mortar (RAM) fire, giving rapid information on the point of origin of the hostile fire as well as an estimate of the impact point. AN/MPQ-64A3 is mounted on a 2.5 ton trailer with an on-board power generator, towed by an armored Family of Medium Tactical Vehicles (FMTV) truck. Additional updates are planned for the FY2016-2022. The Common Platform Upgrade modifies the prime mover for the rotating antenna to a common Army platform, which allows the sensor to receive commands from the Integrated Air and Missile Defense Battle Command System (IBCS) network. The Adjunct Sensor upgrade improves countermeasure protection and threat detection by using a separate S-Band antenna. Identification Friend or Foe (IFF) upgrade adds Mode S support with GPS M-Code capability. AN/MPQ-64A4 In 2019, the U.S. Army selected Lockheed Martin to develop the active electronically scanned array (AESA) variant of the radar. The Sentinel A4 is a complete redesign of the sensor that uses digital processing and solid-state antenna modules based on gallium nitride (GAN) transmitters. The scalable modular architecture is shared with the long-range AN/TPY-4 radar, which has 1000 individually controlled elements and uses GPU computing for signal processing. The AESA antenna allows extended range, faster and more accurate hostile target recognition, and ability to track more threats. It will detect and track small targets, such as Unmanned Aircraft Systems (UAS) and Cruise Missiles, and slow targets, such as UAS and Rotary Wing (RW) aircraft, at low altitudes in clutter and urban settings, with high levels of unwanted signals and echoes generated from physical objects in the environment. Sentinel A4 will be able to contribute sensor data to the Integrated Air and Missile Defense Battle Command System (IBCS) network and Indirect Fire Protection Capability Increment 2. Manufacturer Produced by Raytheon Missiles & Defense. Before its acquisition by the Raytheon Company, the Hughes Aircraft Co. developed the AN/MPQ-64 Sentinel radar at its plant in