一、前言当今世界各军事强国,在发展战略武器的同时,正在不断地强化地面常规部队的作战能力。地面部队的机动能力大大加强了,机械化部队、装甲部队的比重越来越大,直升飞机代替了昔日的战马。因此,威胁来得快,突然遭到袭击的可能性大大增加。在交战过程中,敌人二线部队的增援也迅速,战场的形势瞬息万变。这种状况要求提供一种对战场(包括地面和海面)的远距离、大面积,连续和有效的监视手段。另一方面,为了早在敌人进攻的一开始就给予有力的打 I. INTRODUCTION Every military power in the world today, while developing its strategic arsenal, is constantly strengthening its combat capability on the ground. The mobility of the ground forces has been greatly strengthened, and the mechanized units and the armored units have taken up an increasing proportion. The helicopters replaced the former horses. As a result, the threat is rapid and the probability of a sudden attack is greatly increased. In the course of the war, reinforcements by the enemy second-line units also swiftly and the situation in the battlefield is rapidly changing. This situation calls for a long-range, large-area, continuous and effective surveillance of the battlefield, including the ground and the sea. On the other hand, in order to give a strong fight as early as the enemy attack