The Sentinel is a fifth-generation, state of the line, twin-engine, all-weather tactical Unmanned Combat Aerial Vehicle (UCAV). The Sentinel was designed primarily as a reconnaissance platform, but can also perform precision ground attacks. It typically operates from an aircraft carrier.
The Sentinel is based on the X-47B, which was developed by Northrop Grumman for the U.S. Navy's now-cancelled Unmanned Carrier-Launched Airborne Surveillance and Strike (UCLASS) system.
It also bears a resemblance to the X-47B's successor, the MQ-25A Stingray, which incidentally is also developed by Northrop Grumman for the U.S. Navy's follow-on program to succeed UCLASS, the Unmanned Carrier Aviation Air System (UCAAS).