3.1 Introduction and Definitions ^[1]

As alluded to in the previous chapter, the detection of signals in noise or interference is best described in statistical terms although the use of gaussian wideband noise is not always sufficient to describe performance in a given environment. The first part of this chapter describes the statistics for detection of steady targets in white gaussian ^[2] noise. The discussion is then extended to target signals that have a fluctuating amplitude with various correlation times. This case is essential to prediction of the performance where the target's returns are immersed in clutter signals. This is followed by a brief summary of radar displays and human operator performance. The techniques of detection by sequential, adaptive, or automatic means are covered in Chap. 4.

There is a multitude of excellent texts and papers on the statistics of radar detection [514, 461, 75, 179]. The purpose of this chapter is to summarize the useful relationships on this topic in engineering terms rather than to delve into the theory, Before proceeding, it is essential to define the terminology to be used here. When in parentheses, (S/N) refers to the required signal-to-noise ratio to achieve certain detection statistics.

1. Signal-to-noise ratio S/N: The ratio of the signal power (when the signal is present) to the average noise power after the matched filter but before detection or postdetection integration.

2. Radar cell: A term used to describe a volume from which return signals...