Читать книгу Inverse Synthetic Aperture Radar Imaging With MATLAB Algorithms - Caner Ozdemir - Страница 60

The main goal of a typical radar is to detect the scattered (or backscattered) EM echoes from a target and to extract the information within those EM signatures. The following sequential events happen as the EM wave travels from the transmitter to the receiver:

Figure 2.5 Simulated RCS (in dBsm) of an aircraft model at 2 GHz as a function of azimuth angles.

1 First, the radar signal is generated with the help of the microwave generator (or source).

2 Then the generated signal is transferred to the transmitter by means of transmission lines.

3 The signal is sent out via the transmitting antenna.

4 The radar wave travels in the air and reaches the target.

5 Only some little portion of the transmitted radar signal is captured by the target and reflected back depending on the RCS value of the target.

6 The reflected wave travels in the air, and only a small fraction of the reflected energy reaches back to the radar receiver.

7 The receiver antenna captures some portion of this energy and passes it to the radar receiver.

8 The radar receiver analyzes this scattered signal to obtain the information about the target that may include its location, velocity, direction, RCS, etc.

The radar range equation is the mathematical expression that manifests the analysis of what happens to the signal strength while it goes through the above processes.