Planes must zigzag from one groundbeacon to the next, and ascend and descend in steps at each stage obtaining permission from the ground.
飞机从一个地面信标到下一个信标曲折飞行，在每一阶段都要经过地面的许可才能上升和下降。
2
It can be used in developing the short range radio navigation groundbeacon and testing the performance of its transmitter.
该平台可在近程无线电导航地面导航设备的研制中确定发射机参数和检验性能时使用。
3
Instead of flying straight, planes must zigzag from one groundbeacon to the next, and ascend and descend in steps, at each stage obtaining permission from the ground.