Introduction to Radar Basics - MATLAB Simulations for Radar Systems Design - page 26

ify the MATLAB function Ðpower_aperture.mÑ to compute and plot the power
aperture product for both target types. To this end, the MATLAB program
Ðcasestudy1_1.mÑ, which is given in Listing 1.7 in Section 1.10, was devel-
oped. Use the parameters in Table 1.2 as inputs for this program. Note that the
selection of

is arbitrary.

T e = 290 Kelvin

TABLE 1.2: Input parameters to MATLAB program Ð casestudy1_1.mÑ.

Symbol Description Units Va l u e

snr sensitivity snr dB 15

tsc scan time seconds 2

sigma_tgtm missile radar cross section -10

dBsm

sigma_tgta aircraft radar cross section dBsm 6

rangem missile detection range Km 60

rangea aircraft detection range Km 60

te effective temperature Kelvin 290

nf noise figure dB 8

loss radar losses dB 10

az_angle search volume azimuth extent degrees 360

el_angle search volume elevation extent degrees 10

Figure 1.17 shows a plot of the output produced by this program. The same
program also calculates the corresponding power aperture product for both
the missile and aircraft cases, which can also be read from the plot,

PAP missile = 38.53 dB

(1.74)

PAP aircraft = 22.53 dB

Choosing the more stressing case for the design baseline (i.e., select the
power-aperture-product resulting from the missile analysis) yields

7128.53
Pav

10 3.853 P av × A e = = 7128.53 ⇒ A e = -------------------

(1.75)

1.75 m 2 Choose to calculate the average power as A e =

7128.53
1.75

P av = ------------------- = 4 . 0 7 3 KW

(1.76)

and assuming an aperture efficiency of yields the physical aperture ρ = 0.8

area. More precisely,

A e
ρ

1.75
0.8

2 . 1875 m 2 A == = ----- ----------

(1.77)