F-35 is Visible on Radar

F-35 is Visible on Radar 1 October, 2019

German radar-maker Hensoldt claims to have tracked two F-35s for 150 kilometres following the 2018 Berlin Air Show in Germany in late April of that year. The company claims its passive radar system, named TwInvis, to track the aircraft.

Passive radar equipment computes an aerial picture by reading how civilian communications signals bounce off airborne objects.  Because there are no emitters, passive radar is covert, meaning pilots entering a monitored area are unaware they are being tracked.

Hensoldt previously said its passive-radar detection works regardless of whether the targeted aircraft has radar reflectors (so-called Luneburg lenses) installed. Hensoldt argues that passive-radar detection works in a different spectrum, making the presence (or absence) of reflectors irrelevant. In layman’s terms, passive radar tracks the entire physical shape of planes, versus being triggered by smaller, angular features on the body of a jet.

Issue 86