SAR SIGNAL AZIMUTH AMBIGUITY CANCELLATION

摘要

The invention relates to a method for removing the azimuthal ambiguity, that is to say the Doppler ambiguity, in a SAR receiver on board a moving aircraft, for example an airplane, which makes it possible to have a lower pulse repetition frequency (PRF), without causing range ambiguity. Radar echoes are received on board the aircraft using an antenna having first and second apertures to produce first and second corresponding return signals. The first return signal is processed over a given period of time to generate a first series of SAR component signals representing radar echoes from respective cells of an azimuth-range grid. The second return signal is processed over the given period of time to generate a second series of SAR component signals representing radar echoes from the respective cells of the azimuth-range grid. The component signals, individually weighted, are combined by addition to produce a third series of resulting SAR signals representing radar echoes from the respective cells of the azimuth-range grid. The weighted additive combination of the component signals resolves the azimuth ambiguity, even if the PRF is lower than the minimum PRF generally prescribed by wisdom.