The task for the project "Assessment of sensor systems" was to further develop methodology to assess sensor systems. When performing assessment of sensor systems a good method is required that takes into account all factors such as: the sensor system, tactics, environment, economics, human system interaction, education etc. In this study, we have used a method called COAT/TVS method and further developed the method and tools for sensor assessment. To test the enhanced assessment methodology and tools, an application example has been studied. The application example we have chosen is about assessing the ability of a small Remotely Piloted Aircraft (RPA) system doing reconnaissance against a hostile static operation. To be able to discuss methods and tools, we have chosen to work only with unclassified information. The RPAS and air defense system that have been assessed may differ slightly from the actual sensor systems, as data in some cases have been lacking. In these cases, reasonable values have been assumed. The project also has the task of developing a simulation environment for evaluation of sensor systems. The MSSLab (MultiSensorSimulationLab) simulation environment was developed further for this. In the simulation environment, various sensors are simulated in various environments, weather conditions and time of day. The simulation environment was used in assessment of the RPA system to simulate the sensors in the scenario. In order to make high-quality simulations of sensor systems, all simulation models, such as terrain models, target objects, material classification, scene simulation and sensor models are required to have high quality. This work includes verification of sensor simulations with data from real sensor measurements.