Surface and Volume Clutter - MATLAB Simulations for Radar Systems Design - page 268

c τ
2

-----

ψ g

c τ
2

-----

sec ψ g

R θ 3 dB

A c

R θ 3 dB csc ψ g

Figure 6.5. Footprint definition .

The power received by the radar from a scatterer within A c is given by the

radar equation as

P t G 2 λ 2 σ t
4( 3 R 4

S t = -----------------------

(6.8)

where, as usual, P t is the peak transmitted power, G is the antenna gain, λ is

the wavelength, and σ t is the target RCS. Similarly, the received power from

clutter is

P t G 2 λ 2 σ c
4( 3 R 4

S C = ------------------------

(6.9)

where the subscript C is used for area clutter. Substituting Eq. (6.1) for σ c

into Eq. (6.9), we can then obtain the SCR for area clutter by dividing Eq. (6.8)
by Eq. (6.9). More precisely,

cos
σ 0 θ 3 dB Rc τ

2σ t ψ g

( SCR ) C = ---------------------------

(6.10)

Example:

Consider an airborne radar shown in Fig. 6.4. Let the antenna 3dB beam-
width be θ 3 dB = 0.02 rad , the pulsewidth τ = 2µ s , range R = 20 Km , and