Northrop Grumman LITEF PL41 Mk4 Mod1 Inertial Navigaton System Inertial Navigation System using state-of- the-art digital Ring Laser Gyros in a strap- down configuration for naval applications. The PL41 Mk4 Mod1 is a Naval Inertial Navigation System, using the latest low noise digital Ring Laser Gyros in proven state-of-the-art strapdown technology. The PL41 Mk4 Mod1 is designed for use as the ship’s main reference and navigation system with free inertial or aided navigation capability. The system interfaces with a variety of Logs and embedded or external GPS receivers. Its high level of performance meets both naviga- tion and fire control system requirements for all sizes and types of surface vessels and submarines. It measures motion along and around the three principle axes of the vessel providing heading, roll and pitch as angles and angular rates, acce- lerations, velocities, position and heave. Features • Very low noise digital Ring Laser Gyro (RLG) with an MTBF of over 200,000 hours • System MTBF of over 10,000 hours • MTTR of less than 30 minutes • Full built-in test capability • IMU and all electronic cards can be exchanged at sea • High data sampling and update rates for mini- mal data staleness • Automatic switching from align to operate modes • Solid-state technology • Short alignment time alongside and at sea • Supports static and dynamic angle simulation • Supports wide variety of digital and synchro interfaces Advantages • Very low maintenance and through life costs • High system reliability • High system availability • Easy maintenance • High in-service mission time • Increases combat system effectiveness • Simple operation • Very low structure borne noise for submarine applications • Fast system readiness for vessel operation • Provision of an in harbour functional test of all connected user systems • Flexible interface concept to meet all customer requirements • Full compatibility and exchangeability with in- service PL41 Mk3 systems