albersheim

Required SNR using Albersheim's equation

Syntax

SNR = albersheim(prob_Detection,prob_FalseAlarm)
SNR = albersheim(prob_Detection,prob_FalseAlarm,N)

Description

SNR = albersheim(prob_Detection,prob_FalseAlarm) returns the signal-to-noise ratio in decibels. This value indicates the ratio required to achieve the given probabilities of detection prob_Detection and false alarm prob_FalseAlarm for a single sample.

SNR = albersheim(prob_Detection,prob_FalseAlarm,N) determines the required SNR for the noncoherent integration of N samples.

Examples

Compute the required single sample SNR for a detection probability of 0.9 as a function of the false-alarm probability.

Pfa=0.0001:0.0001:.01; % False-alarm probabilities
Pd=0.9; % probability of detection
SNR = zeros(1,length(Pfa)); % preallocate space
for j=1:length(Pfa)
    SNR(j) = albersheim(Pd,Pfa(j));
end
plot(Pfa,SNR,'k','linewidth',2);
axis tight;
xlabel('Probability of False Alarm');
ylabel('Required SNR (dB)');
title('Required SNR for P_D=0.9 (N=1)');

Compute the required SNR for 10 noncoherently integrated samples as a function of the false-alarm probability with the probability of detection equal to 0.9.

Pfa=0.0001:0.0001:.01; % False-alarm probabilities
Pd=0.9; % probability of detection
SNR = zeros(1,length(Pfa)); % preallocate space
for j=1:length(Pfa)
    SNR(j) = albersheim(Pd,Pfa(j),10);
end
plot(Pfa,SNR,'k','linewidth',2);
axis tight;
xlabel('Probability of False Alarm');
ylabel('Required SNR (dB)');
title('Required SNR for P_D=0.9 (N=10)');

More About

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Albersheim's Equation

Albersheim's equation uses a closed-form approximation to calculate the SNR. This SNR value is required to achieve the specified detection and false-alarm probabilities for a nonfluctuating target in independent and identically distributed Gaussian noise. The approximation is valid for a linear detector and is extensible to the noncoherent integration of N samples.

Let

A=ln0.62PFA

and

B=lnPD1PD

where PFA and PD are the false-alarm and detection probabilities.

Albersheim's equation for the required SNR in decibels is:

SNR=5log10N+[6.2+4.54/N+0.44]log10(A+0.12AB+1.7B)

where N is the number of noncoherently integrated samples.

References

[1] Richards, M. A. Fundamentals of Radar Signal Processing. New York: McGraw-Hill, 2005, p. 329.

[2] Skolnik, M. Introduction to Radar Systems, 3rd Ed. New York: McGraw-Hill, 2001, p. 49.

See Also

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