In order to assess the overall value of a sensor system the performance must be measured in tactically relevant situations. It is important to be able to measure performance of both individual sensors and for the entire sensor system in various environments, weather conditions and time periods. This report from the project "Assessment of sensor systems" describes methods and tools that can be used to measure performance of optronic systems and radar systems. A selection of these methods and tools have been tested to analyze their usefulness. The described methods and tools can be used by the Swedish Armed Forces in assessments and studies. They can also be used to provide a basis for development, purchase or upgrade of new sensor and system capabilities. To develop the ability to assess sensor systems the project further develops an assessment method COAT / TVS.