Improvements for air-surveillance radar

Both a near-term and a far-term radar concept for improved air-surveillance are described. The near-term concept is based on operating simultaneously with multiple frequencies over two radar bands to obtain the benefits of more uniform coverage in elevation, improved target detection, improved automatic tracking, target height-finding without the need for a 3D antenna, elementary target recognition, and other attributes that result from operating over a very wide band. The far-term concept is based on operating an air-surveillance radar with a very wide bandwidth as in the near-term approach, but with an architecture quite different from that used in current air-surveillance radars. This radar looks everywhere all the time with a number of fixed directive receiving beams and an omnidirectional transmitting beam. The spatial, temporal, and spectral domains are used along with digital beamforming and digital signal processing to allow this ubiquitous radar to perform multiple functions in parallel with variable data rates and without time sharing so as to achieve simultaneous weapon control and surveillance, reduced susceptibility to intercept, and other capabilities difficult to obtain with conventional analog beamforming methods