Abstract
We can define the airborne system proposed in this book as an airframe that works on the enemy side, so it is in danger of attack from the enemies' missiles systems and detected by radars. Therefore, the need to support this system with immunity from these threats is important for the safety of this system. After proposing the advanced method for high speed target detection in the presence of clutter and jamming, now the authors discuss how to support this system with immunity against ground radar and missile stations. The deception jammer is a type of spoofing radar. As discussed in Chapter 2, the digital radio frequency memory (DRFM) will be used to generate the deceptive jamming, and the sub-Nyquist sampling theory will be used to improve the performance of the jammer. In addition, chaotic algorithm is proposed to give more improvement to the jammer source.
TopSignal Model And Geometry Of The Model
Jammer source is supposed to be placed on airborne radar, and the victim is ground monostatic radar. The airborne jammer is embedded on the plane, the origin point is the center of the airborne radar. The radar motion, is described by the circular motion and its rotational rate is defined as , because the jammer source is on the airborne radar so the distance between the airborne radar and the ground monostatic radar is equal to the distance between the jammer source and the radar and equals , the airborne radar has scatterer points and the position of each point is , and the angle between any scatterer point and x axis is (rad/s), the geometry of the airborne radar carrying deception jammer source and the monostatic radar is illustrated on Figure 1. Suppose that the monostatic radar transmit linear frequency modulated (LFM) signal with central frequency , the pulse width is , and the chirp rate is , the signal formulation is as follows (Candès & Wakin, 2008). Figure 2 shows the screen of the ground radar, we can see the true targets and the false targets generated by the ASDJ:
(1) where
is the monostatic radar transmitted signal,
is the fast time,
is the slow time,
is the total time, and:
(2)Figure 1. The geometry of the ground monostatic radar, and the jammer source on board of airborne radar
Figure 2. False targets and true target on the ground radar screen