An encoding SAR-transponder for target identification

A coded transponder was developed for operation in C-band and verified using the SAR sensor of the Active Microwave Instruments (AMI) on the ERS-1 and ERS-2 satellites. The coded transponder uses signal modulation techniques which affect the SAR signal in both range and azimuth and decouples the transponder signal from the background signal. Encoding adds additional features without losing any of the advantages transponders have over passive targets.