| 摘要 |
A lens such as a Luneberg lens is used in a retro-reflector having a plurality of reflector elements formed in a mosaic covering a predetermined portion of the lens. Each of the reflector elements may be individually controlled independently of the others; in this way, an interrogation source whose direction can be determined can have its interrogation signals reflected back only to it by having only one or a selected few of the reflector elements act as reflectors. Reflection in other directions may be suppressed by causing the other mosaic elements to act as absorbers. In addition, the reflectors can have their reflective or transmissive properties modulated so as to act as amplitude or phase modulators of the interrogation signal. In this way, information can be imparted to the reflected interrogation signal. Doppler effects, on account of the velocity of a vehicle upon which the retro-reflector is mounted, are corrected for each of the individual reflector elements depending upon their positions on the Luneberg lens in relation to the vehicle and its direction of motion and velocity. The lens can be arranged with fixed elements in a pattern with symmetry about an axis of rotation of the lens; such elements need not be fixed, however, and may also be individually controlled or controlled as a group in a pattern.
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