飞行试验阶段 meaning in English

flight test portion
flight-test stage
flying stage
flying test stage

In consideration of the special mission characteristics and technical requirement of high altitude long endurance unmanned aerial vehicle , an authentic real - time and space - time windfield integrated model is accomplished to take atmosphere environment influences into account . at the same time , we should analyze the dynamics the uav encounters dispersedly , so the " finite scale " aircraft concept is quoted
根据长航时无人机的特殊飞行任务特点和技术要求，在飞行试验阶段，有必要综合考虑飞行环境中各种大气干扰因素的影响，为无人机设计与仿真提供一个真实、适时的风场时空分布模型。