radareqsearchpap

Compute the power-aperture product for a search radar that is required to detect a 1 square meter RCS target at a range of 111 kilometers. Assume the antenna rotates at a rate of 12.5 RPM, the signal-to-noise ratio required to make a detection is 13 decibels, the system noise temperature is 487 Kelvin, and the total system loss is 20 decibels.

range = 111e3;
tsearch = 60 / 12.5;
snr = 13;
ts = 487;
loss = 20;

The radar traverses a search volume with azimuths in the range [–180,180] degrees and elevations in the range [0,45] degrees. Find the solid angular search volume in steradians by using the solidangle function.

az = [-180;180];
el = [0;45];
omega = solidangle(az,el);

Calculate the power-aperture product. By default, the target RCS is 1 square meter.

snr = radareqsearchpap(range,snr,omega,tsearch,'Ts',ts,'Loss',loss)

snr = 
2.3689e+04

Plot the power-aperture product as a function of the required SNR for a search radar system located at a range of 100 kilometers. Incorporate path loss due to absorption into the calculation of the power-aperture product.

Specify the required SNR as values in the range [–5,25] decibels. Assume the search volume is 1.5 steradians and the search time is 12 seconds.

range = 100e3;
snr = -5:25;
omega = 1.5;
tsearch = 12;

Find the path loss due to atmospheric gaseous absorption by using the gaspl function. Specify the radar operating frequency as 10 GHz, the temperature as 15 degrees Celsius, the dry air pressure as 1013 hPa, and the water vapor density as 7.5 $\mathrm{g}/{\mathrm{m}}^3$.

freq = 10e9;
temp = 15;
pressure = 1013e2;
density = 7.5;
loss = gaspl(range,freq,temp,pressure,density);

Compute the power-aperture product. By default, the target RCS is 1 square meter.

pap = radareqsearchpap(range,snr,omega,tsearch,'AtmosphericLoss',loss);

Plot the power-aperture product as a function of the required SNR. Before plotting, convert the power-aperture product from $\mathrm{W}\cdot {\mathrm{m}}^2$ to $\mathrm{kW}\cdot {\mathrm{m}}^2$.

plot(snr,pap*0.001)
grid on
xlabel('SNR (dB)')
ylabel('Power-Aperture Product (kW\cdotm^2)')
title('Power-Aperture Product vs. SNR')