High Resolution Tactical Synthetic Aperture Radar (TSAR) - MATLAB Simulations for Radar Systems Design - page 588

Pulses (Azimuth Cells)) Pulses (Azimuth Cells))

. . . . . .

23 23 M M

1 1

1 1

2 2

3 3

.
.
.

.
.
.

N N

Figure 12.4b. Definition of a resolution cell.

where is the pulsewidth. From the geometry in Fig. 12.5 the extent of the
range cell ground projection

τ

∆ R g is computed as

c τ
2

-----

∆ R g = sec ψ g (12.6)

The azimuth or cross range resolution for a real antenna with a 3 dB beam-

width θ (radians) at range R is

∆ A = θ R

(12.7)

However, the antenna beamwidth is proportional to the aperture size,

λ
---

θ ≈ (12.8)

where λ is the wavelength and L is the aperture length. It follows that

λ R
L

∆ A = -------

(12.9)

And since the effective synthetic aperture size is twice that of a real array, the
azimuth resolution for a synthetic array is then given by