www.radartutorial.eu Radar Basics

Probability of Detection PD

The received and demodulated echo signal is processed by a threshold logic. This threshold shall be balanced so that as of a certain amplitude wanted signals being able to pass and noise will be removed. Since in the mixed signal exist high noise tops which lie in the range of small wanted signals the optimized threshold level shall be a compromise. Wanted signals shall on the one hand reach the indication as of a minimal amplitude, on the other hand the false alarm rate may not increase.

Probability of detection PD is the ratio of detected aims to the number of all possible blibs on the radar screen, i.e. all possible targets in a given direction.

PD = detected targets · 100% (1)

sum of all possible blibs

The radar must detect, with greater than or equal to 80% probability at a definied range, a one square meter radar cross section. This relatively bad result is a compromise between the probability of detection and the false alarm rate. This means: One of five targets wont be detected by a radar with analogue signal processing.

The older term “Blip Scan Ratio” was renamed to as “Probability of Detection”.