Radar Waveforms - MATLAB Simulations for Radar Systems Design - page 157

Stepped Frequency Waveforms 159

∆ fc 2 E ≤ ⁄ (3.71)

where is the target extent in meters. E

Additionally, the pulsewidth must also be large enough to contain the whole
target extent. Thus,

∆ f ≤ 1 τ' ⁄

(3.72)

and, in practice,

(3.73)
This is necessary in order to reduce the amount of contamination of the synthe-
sized range profile caused by the clutter surrounding the target under consider-
ation.

∆ f ≤ 12τ' ⁄

MATLAB Function Ðhrr_profile.mÑ

The function Ðhrr_profile.mÑ computes and plots the synthetic HRR profile
for a specific SFW. It is given in Listing 3.3 in Section 3.12. This function uti-
lizes an Inverse Fast Fourier Transform (IFFT) of a size equal to twice the
number of steps. Hamming window of the same size is also assumed. The syn-
tax is as follows:

[hl] = hrr_profile (nscat, scat_range, scat_rcs, n, deltaf, prf, v, r0, winid)

where

Symbol Description Units Status

nscat number of scatterers that make up

the target

none input

scat_range vector containing range to individ-

ual scatterers

meters input

scat_rcs vector containing RCS of individual

scatterers

meter square input

n number of steps none input

deltaf frequency step Hz input

prf PRF of SFW Hz input

v target velocity meter/second input

r0 profile starting range meters input

winid number>0 for Hamming window

number < 0 for no window

none input

hl range profile dB output