The fundamental task of a radar is target detection, that is, determining whether or not a target exists. Over time, however, expectations have grown regarding the information that radar can obtain. Today, besides target detection, many parameters can be estimated-such as velocity and position-about many kinds of targets, and targets can also be classified with modern radar units. Technological developments in electronic systems and signal processors mean that returned signals from a target can be analyzed with a high degree of precision, so the returned signal is more valuable today when compared to the early days of radar systems.