Synthetic aperture radar for object identification by aircraft or space vehicle

摘要

The synthetic aperture radar is calibrated using a transponder. The transponder receives signal pulses emitted from the SAR and converts them to intermediate frequencies. These intermediate frequencies trigger a code generator (12) which phase modulates the IF signal, which is then converted back up to a frequency which is the same or different from that received, amplified and transmitted. This enables the transponder to be identified. The SAR processes the signals from the transponder to provide a display on which the transponder is clearly visible, or alternatively so that it is defocussed.