In the modern defence different sensor systems has great influence, both as direct sources of information and as a part of the chain of decision making. The demand for performance, flexibility, mobility and rapid deployment in highly different environment is a great challenge. Together with economic realities this puts restrains on available systems to choose from. Further more are the systems functionality in a given situation and in different geographical environments hard to predict. The ability to assess complex systems is therefore of great importance. This pilot study is a step in the armed forces and FOI´s process of increasing the ability to assess sensor systems based on a tactical and ability based perspective During this work we have studied a method called COAT that is recently developed at FOI for assessment of complex communications systems. The method is based on the customer needs and takes account of the tactical situation and environment. Our study indicates that the COAT method is suitable as a base for a development of an assessment method for sensor systems. If this is done, much of the previous work and experience can be reused. The method however must be adapted for use for sensor systems and needs further development. This development will also lead to a higher degree of cooperation between the areas of communications and sensors as they will basically have the same assessment method. Thereby the total sum of assessment competencies at FOI will increase and the two areas will benefit from the development.