The Defense Advanced Research Projects Agency (DARPA) is soliciting innovative approaches to address challenges in the following technical area: Frosty will develop technology to produce new sensing m... The Defense Advanced Research Projects Agency (DARPA) is soliciting innovative approaches to address challenges in the following technical area: Frosty will develop technology to produce new sensing modes in the Arctic environment, enabling better detection and tracking of low-flying air vehicles and slow-moving maritime vessels. Development of innovative radar signal processing algorithms and analysis approaches are needed to enable the proposed concept.