  After a brief introduction to the notion of quantum entanglement and quantum
correlations, several schemes for a quantum radar based upon the quantum
illumination and others protocols are discussed. We review different concepts
that have been introduced to overcome several of the inherent difficulties in
the implementation of quantum generation and/or detection quantum sensing
protocols for RADAR applications. Our review is an up-to date critical
presentation of the state of the art, with emphasis in the case by case
assessment of the feasibility of the different concepts. We also aim that the
review is accessible to non-experts in the field. Hence several appendixes and
a technical glossary are included.
