A proposed multimodal FM/CW aircraft radar for use during ground operations

A proposed forward looking, relatively small and inexpensive, multimodal radar is described. The design objective is to determine range, range rate, and bearing to targets at 2-500 m, at operational speeds, and at +or-8.5 degrees either side of boresite. For this open-loop, wide-angle, expanded monopulse-like, FM/CW radar, it is planned to time-share the transmitted power to TE/sub 10/, TE/sub 20/, and TE/sub 30/ rectangular waveguide modes that, in turn, drive a small aperture horn antenna. By transmitting and receiving on the different modes, six independent views of the forward direction are obtained. Echoed returns into the transmitted mode are used to find range and range rate. Returns into all three modes are frequency integrated to reduce angle noise, then ratioed to obtain target angle. This inexpensive control radar, which is termed cradar, quickly obtains a two-dimensional forward plot of the protected pathway without moving parts.<>