Guest editorial: Passive high resolution and imaging radar

Passive radar has made consistent and significant steps ahead and it is nowadays considered as a viable and complementary technology to active radar. Passive radars are not only able to detect and track targets, but they can also produce target's high-resolution profiles and radar images, as widely demonstrated in the literature. In this Special Issue, recent advancements in the area of passive radar imaging are showcased with a collection of papers that cover both passive synthetic-aperture radar (SAR) and inverse synthetic aperture radar (ISAR) imaging