Fraunhofer IOSB (Ettlingen, Germany) developed and built a measurement system to verify laser threat detection. The system has been given the name MARLA (Maritime Lasermessanlage), eng.: maritime laser measurement system. It is an integral part of an exercise and test range for electronic warfare of the German Navy at Wehrtechnische Dienststelle für Schiffe und Marinewaffen, Maritime Technologie und Forschung WTD 71, Eckernförde, Germany.<p> </p> The system provides realistic simulations of various laser-based threats to ships on sea and allows studies of the efficacy of onboard laser warning receivers. MARLA assists laser counter-measures and enables to include environmental studies (atmospheric transmission, water reflections etc.). Redundant system design ensures laser safety even in public areas.<p> </p> The core of MARLA is a modular laser unit (LU) consisting of five laser modules (LM) and the dedicated laser controllers (LC). The laser modules are mounted on a pan-tilt positioner. MARLA covers the most common laser threats like laser target designator (LTD), laser range finder (LRF), laser beam rider (LBR) and laser dazzler (LD). The individual laser modules are based on commercially available laser sources fitted with multi-stage attenuators to set the laser irradiance within a range of seven orders of magnitude without losing beam quality. By means of a photo detector, the energy of the emitted laser pulses is recorded. An integrated beam shaper enables to vary the beam divergence.<p> </p> The further crucial parts of MARLA are the control and data acquisition system with operating and visualization software and a general laser safety monitoring system. All the subsystems are integrated into a climate-controlled movable 20' sea container. Use of a stand-alone verification system provides reference data to verify the actual on-site irradiation at the test target.