TABLE OF CONTENTS Key technology issues for improving the detection performance of AEW radar include increasing the physical size of the antenna, as well as the average transmitted power, the attainment and maintenance of ultralow antenna sidelobes, very wide dynamic range analog and digital receiver sections, high-speed analog-to-digital converters (ADCs) of increased dynamic range, and CFARs of improved efficiency for automatic target detection and clutter rejection.
As previously noted, ground clutter is a principal deterrent to lowering the RCS detection capabilities of existing AEW radars. Therefore, for subsystems relating to clutter processing, there are very high performance requirements, namely,
ultralow sidelobe antennas and radomes
wide dynamic range analog receiver front ends
wide dynamic analog-to-digital converters (ADCs)
precision timing circuits
highly stable coherent transmitters and receivers
In addition to reduced sidelobe levels, the requirements for improvements in AEW antennas include
larger aperture area normal to target direction for reducing the average transmit power required for detection of low RCS targets
increased aperture height for improved elevation measurements
increased aperture width for improved azimuth measurements and reduced Doppler spreading (for low- and medium-PRF systems) of ground clutter due to aircraft motion.
When 360 degrees of azimuth coverage is a requirement for AEW, the listed requirements on dimensions will cause substantial increases in aircraft frontal and aft areas. Consequently, attainment of the desired increased antenna dimensions may create an appreciable increase in aerodynamic drag, thereby causing both an unacceptable reduction in available AEW time on station and increases in aircraft operating costs.
