For instance, one plane with a special transponder could send out a string of false echoes. This could make one red-herring plane look Like an entire formation of attackers.

The reasons of the paired false target echoes are analyzed and the paired echoes are divided into two types, one is called "undersampled type" and anather, "velocity mismatched type".

Then, the PCI7300 A card is used to acquire the radar echoes, and the signal is processed in time domain, focused on targets identification and false targets elimination.