Jamming by deception
Figure 1: Jamming by deception
Deception uses ECM to forge false target signals that the radar receiver accepts and processes as real targets. The pulse repetition frequency of the false target signals are:
- either unsynchronous to the pulse repetition frequency of the radar
unit and the interfering pulses writes narrow scroll-shaped sectors on the monitor, or
- either synchronous to the pulse repetition frequency of the radar unit or even is derived from the radar units own transmitting impulse. (Repeater Jammer). The impulse sent out to the deception then has another range, another azimuth or another speed than the true aim sign.
See the picture: in azimuth of 135° seven targets appear behind each other. Obviously these are a deception disturbance since they e.g. are wider than it has the own antenna diagram expected.
Such deceptions are unmasked by changing the pulse repetition frequency specifically.