The paper deals with the problem of the detection and the estimation of parameters of radar signals in the Gaussian white noise from the point of view of the theory of statistical decision. The design principle of the optimum radar receiver for signals of unknown parameters is given according to the characteristics of the high-speed target at distance and to the purposes of radar systems. Unified detection procedures are established the construction and the performances of the optimum radar receivers are obtained.The block diagrams of these results are also shown.Emphasis is given to the case where the prior distributions are unknown

while only two parameters

velocity and distance

are discussed for the case where the prior distributions "re known. For the latter case

the optimum estimations of these two parameters and their properties are derived from the absolute loss criterion.