Radar and antiairocraft gun positions protect a beach in southern France.

Radar and antiairocraft gun positions protect a beach in southern France. Carefully revetted antiaircraft and radar positions protect a beach in southern France. The 90 mm. guns are automatically aimed and directed to follow the moving target by the radar set at the far right. Its antenna has been obscured for reasons of military security. Radar involves direction finfing and ranging, and is the basis of the defense against aircraft attack. It involves microwave techniques only dimly understood at the beginning of the war. Radar was devoloped by U.S., britisch, French and German scientist working independently until 1940, when the offerts of American and Britsh scientist in this field were exchange scientific information of a military nature