Radar

Note the white cone shapes.
They portray enemy Air Radar coverage and appear when you select "Stealth Mode". If you keep your plane out of the cones you are unlikely to be detected, or at least while gain precious time before you are detected.

Your aircraft is at the bottom of the display.

From the manual -

" On the radar, unidentified traces are shown in orange, while the designation of the currently selected trace is shown as unknown on the HUD. At closer ranges, an unidentified trace may gain a category designation, such as fighter or bomber, but remains an unknown trace in terms of aircraft type and allegiance.

At closer ranges, Non-Cooperative Target Recognition will identify the type of aircraft and Identify Friend or Foe (IFF) systems will determine the allegiance. "