The USAF F-22 Engineering, Manufacturing and Development (EMD) program has pushed the state of airborne fire control radar technology well beyond that found in today's fielded systems. Advancements in performance, reliability, and low observability have been realized in the design of the F-22's new APG-77 Radar through the implementation of active array technology, low noise receiver components, high density packaging, and advanced mode development. This paper will explore these advanced features from a systems engineering perspective by first introducing the F-22 Avionics System concept and then summarizing the hardware and software architecture which comprises the F-22 radar system. Unique F-22 advancements in survivability, lethality, reliability, and supportability are outlined briefly. Aircraft trade considerations that are unique to the implementation of an active array into a low radar cross section fighter application are discussed. Lessons learned in design trade areas such as power, cooling, packaging, weight, low radar cross section considerations, receiver design, antenna design, reliability, supportability, maintainability, and waveform design are reviewed. Implementation of this new capability would not be possible without the incorporation of new development processes and the transition of critical technology made available through the benefit of several long term joint government-industry technology base initiatives. Related details regarding solid state transmit/receive modules, electronically scanning arrays, and advanced radomes extending back to the Advanced Tactical Fighter Demonstration/Validation phase of the F-22 program are reviewed.
