In order to perform accurate assessment of sensor systems with simulation based methods, high quality simulations are required. The task for the project Assessment of sensor system is to develop a modular sensor system simulation program that can simulate sensor systems in various environments, weather conditions and time periods. The simulation tool that is further developed is the MSSLab (MultiSensorSimulationLab). Accurate simulations of sensor data require that all simulation models e.g. terrain models, target object, material classification, scene simulation and sensor models are of high quality. We are aiming at with this report to describe the status of work with scene simulation and sensor models in MSSLab. The last years a lot of work has been performed to verify sensor simulations of IR imaging of both people and vehicles. The result shows that the dynamic range of the simulations should be increased. A detection algorithm has been tested against both measured and simulated data and the result shows that the detector gives similar results and is thus not so sensitive to the difference in dynamics. Various signal processing algorithms are integrated in MSSLab as e.g. target detection, target tracking and sensor planning. These have been used to study reconnaissance from both combat vehicles and from UAV. Several simulations have been carried out in the project to explore the UAV operators' abilities to detect hostile people from a UAV. The analysis showed that the methodology to simulate sensors in MSSLab to study UAV operators' abilities to detect hostile people worked satisfactory.