The AN/SPY-2 radar is an add-on to the AEGIS battle management system radar; it gives new capabilities needed for ballistic missile defense that are not part of the basic AN/SPY-1 main AEGIS radar. It is the engagement control radar for the RIM-161 Standard SM-3 missile.
Known as the High Power Discriminator (HPD), it gives long-range detection, tracking and discrimination of advanced theater ballistic missile (TBM) threats. Radar targets associated with such threats are very different in speed, geometry, and distance than the aircraft and cruise missile targets for which AN/SPY-1 is optimized.
While it will physically be mounted with the AN/SPY-1 on Burke-class or Kongo-class destroyer or a Ticonderoga-class cruiser, other radars, such as the Army transportable AN/TPY-2 or the Navy's sea-based X-band (SBX) ship used in BMD development, have some common characteristics. Other sensors, while not radars, complement the BMD mission by detecting launch, such as the present Defense Support Program or the future Space-Based Infrared System (SBIRS).
- "SPY-2 High-Power Discriminator (HPD) radar", GlobalSecurity