This report from the Swedish Armed Forces' thematic research programme Unmanned Vehicles and Cyberthreats summarizes results from an assessment of three unmanned aerial systems' capabilities in the context of territorial area surveillance 2030 for the Swedish Armed Forces. The assessment is based on a scenario where a number of radar-equipped unmanned aircraft systems are to perform surveillance over the Baltic sea during a time period of a month. Focus is on the systems' ability to give early warning of incoming cruise missiles. An overall conclusion is that all assessed systems has the capability to provide sustainable surveillance and contribute to the general air space situational awareness beyond the ground based radar systems. For early warning of incoming cruise missiles it is only the largest system with the most powerful onboard radar which can give the operator the capability of early warning in a larger area. The limited radar performance for the smaller systems is only effective if the operator beforehand can pin-point the area where the threat is expected to appear. Smaller systems comes on the other hand, due to lower cost, most likely in a larger number which turns out to be necessary for a month's sustained surveillance. To operate withdrawn, away from the high threat environment, in order to minimise risk will not, even for the best system, work without losing the early warning capability of cruise missiles. The Swedish Armed Forces need to develop methods and concept to operate this type of systems in a high threat environment. Some of the important components of such a strategy, which are elaborated on in this report, are robust telecommunication able to cope with electronic warfare, automatic functions able to adapt routing if the link is lost and hard protection from anti-aircraft systems or escort. Developments in emerging technologies as stealth platforms, bi-static sensor solutions and optionally piloted systems should be monitored. The assessment also shows that the smaller systems, which have the lowest performance in the context of territorial area surveillance, have the largest potential in other defence applications such as signal intelligence, sea surveillance, supporting ground forces with brigade surveillance, deployment in international operations or support to the civil society in general. With a limited budget, the Swedish Armed Forces need to do a thorough analysis of the inherent capability trade-off between the choice of procuring very few large, or many smaller, unmanned aircraft systems.