Evolution of naval AESA radars

Modern radar development is driven by an evolving and expanding range of threats. The low end of the threat spectrum is composed of small, slow-moving targets such as UAVs or small surface vessels. At the high end of the threat spectrum there is an increasing number of very fast missiles, up to the level of (Tactical) Ballistic Missiles. Furthermore, the mission environment has evolved as well, which is illustrated on the naval side by increased operations in littoral environments, often in an asymmetric warfare setting. Active Electronically Scanned Array (AESA) radar systems are uniquely suited to operate in these operational and threat environments, where the flexibility and redundancy of AESA systems give them an edge over more conventional solutions. Active array systems have been in use for more than a decade now (e.g., the APAR X-band system). Typically, these systems use RF beamforming or 1D Digital Beamforming (DBF). Recent advances in technology have made it possible to extend these beamforming concepts to full 2D digital beamforming, also known as Dual Axis Multi-beam. This results in additional flexibility and possibilities on a system level. This paper describes the underlying technology evolution and the added functionality and flexibility that is achieved with such systems.