GCA radars: Their history and state of development

The evolution and state of development of the radars used in the Ground-Controlled Approach (GCA) systems of the U.S. Air Force is described. Emphasis is placed on the radar requirements of this application and the evolution made possible by the advances in component technology. We first review the concept of GCA operation and show how this leads to the requirements of the two radars in the system. Next we discuss the early history of GCA and the AN/MPN-1, the first operational system. The evolution of the GCA radars since the AN/MPN-1 is then summarized. Finally, we describe in more detail the AN/TPN-19. This is the most recent GCA system to be developed, and it makes effective use of array technology, frequency diversity, monopulse, pulse compression, and computer control.