Luttrell S P, January 1987, A proposal for a new method of calibrating radar sensitivity, RSRE technical report (Malvern, UK), BS1/37
We derive an invariant form for the degree of overlap of a pair of probability density functions. The invariance property is such that the functional form of the overlap expression is the same for all underlying coordinate systems which are related by nonsingular transformations. A particular application of these results is in the definition of a new calibration procedure for quantifying the ability of a radar system to discriminate between signal plus noise and noise alone. The invariance property of our definition ensures that the underlying receiver law (e.g. linear or logarithmic) does not need to be known in order to conduct the calibration. We present a practical means of implementing our new calibration procedure, and for ensuring that it is consistent with the old 'tangential method'.