the main radar is a raytheon dual-mode synthetic aperture radar / moving target indication (sar/mti) radar known as sentinel dual mode radar sensor (dmrs). it uses aesa active electronically scanned array technology. raytheon claim it could be modified to match the maritime surveillance capability of the cancelled nimrod mra4, and the ground stations could be adapted to receive data from watchkeeper, mq-9 reaper and the future scavenger programme. a contract for the development of a maritime capable software upgrade will be placed in the spring of 2015; jane's speculates that this would allow the sentinel to detect surface vessels and potentially submarine periscopes and that other sensors could be fitted as a 'low-end' capability for maritime surveillance to complement a 'high-end' platform such as the p-8a poseidon.