arrayscanloss

Loss due to electronic scanning off broadside

Syntax

LSS = arrayscanloss(PD,PFA,N)

LSS = arrayscanloss(___,THETAM)

LSS = arrayscanloss(___,SW)

LSS = arrayscanloss(___,'CosinePower',COSINEPOWER)

Description

LSS = arrayscanloss(PD,PFA,N) returns the two-way statistical scan sector loss for a radar with a phased array antenna that electronically scans a sector from -60 to +60 degrees off broadside. The computation assumes a square-law detector and a nonfluctuating target.

LSS = arrayscanloss(___,THETAM) computes the scan sector loss given the scan sector limits specified about the broadside direction.

LSS = arrayscanloss(___,SW) computes the scan sector loss for radar echoes received from a chi-squared distributed target specified by the Swerling case.

LSS = arrayscanloss(___,'CosinePower',COSINEPOWER) specifies the exponent of the cosine modeling the gain loss of an array scanned off broadside. This exponent takes into account two effects that result in the gain reduction due to array scanning. The first effect is the beam broadening due to the reduced projected array area in the beam direction. The second effect is a reduction of the effective aperture area of the individual array elements at off-broadside angles.

Examples

Plot Statistical Scan Sector Loss Phased Array Radar Antenna

Compute the statistical scan sector loss for a radar with a phased array antenna. The array scans from -45 to 70 degrees about the broadside direction. Assume a single pulse is received from a Swerling 1 case target by a square-law detector and the probability of false alarm is set to 1e-6. Plot the computed loss as a function of the desired probability of detection.

Pd = 0.1:0.01:0.99;         % Detection probabilities
Pfa = 1e-6;                 % Probability of false alarm
N = 1;                      % Number of received pulses
ThetaM = [-45 70];          % Scan sector limits
Lss = arrayscanloss(Pd,Pfa,N,ThetaM,'Swerling1');

Plot the statistical scan sector loss.

plot(Pd,Lss)
xlabel('Probability of Detection')
ylabel('Loss (dB)')
title('Scan Sector Loss vs P_d for Swerling 1 Target')
grid on

Input Arguments

PD — Desired probability of detection

scalar | J-length vector

Desired probability of detection, specified as a scalar or J-length vector between 0.1 and 0.999999.

Data Types: double

PFA — Probability of false alarm

scalar | K-length vector

Probability of false alarm, specified as a scalar or K-length vector between 1e-15 and 1e-3.

Data Types: double

N — Number of received pulses

positive scalar

Number of received pulses, specified as a positive scalar.

Data Types: double

THETAM — Scan sector limits

[-60 60] (default) | scalar | two-element vector

Scan sector limits, specified as a scalar or two-element vector. If THETAM is a scalar, then the scan sector spans from -THETAM to +THETAM. If THETAM is a two-element vector of the form [theta1 theta2], the scan sector spans from theta1 to theta2. The default value is [-60 60]. Units are in degrees.

Data Types: double

SW — Scan sector limits

'Swerling0' (default) | 'Swerling1' | 'Swerling2' | 'Swerling3' | 'Swerling4' | 'Swerling5'

Scan sector limits, specified as the Swerling case for the chi-squared distributed target. The default value of SW is 'Swerling0'.

COSINEPOWER — Gain loss cosine exponent

2.5 (default) | positive scalar

Exponent of the cosine modeling the gain loss of an array scanned off broadside, specified as a positive scalar. Typically, the exponent value lies between 2 and 3. The default value is 2.5.

Data Types: double

Output Arguments

LSS — Two-way statistical scan loss

J-by-K matrix

Two-way statistical scan sector loss, returned as a J-by-K matrix, where J and K are the dimensions of the PD and PFA arguments. Units are in decibels (dB).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Version History

Introduced in R2021a