高速飞行器非视距短波通信的可行性验证飞行试验

当高速飞行器处于失稳失控等紧急情况时，现有航天器测控方法可能面临地面站天线无法及时跟踪和对准飞行器的问题，这将导致测控通信链路的中断，无法传输紧急的安控遥控指令。为了在飞行器失稳失控、非视距通信时与地面站维持通信，提出将短波通信应用于高速飞行器测控通信系统的应急通信，并进行非视距短波通信的飞行试验以验证方法的可行性。在试验中，地面站发射7 MHz的短波信号，高速飞行器内部安装的交流磁场计用于接收短波信号，获得了短波的磁场强度与飞行环境的本底噪声。试验结果表明，随着飞行器海拔的增加，磁场强度减小，高速飞行器始终能在非视距和天线不对准的情况下接收到短波信号，证实了短波应用于高速飞行器应急通信的可行性。试验是进一步验证高速飞行器在远距离、超视距以及拒止环境下应急通信的技术基础，同时，也为高速飞行器短波通信系统的研制提供重要的数据支撑。

Flight experimental investigation on shortwave communication of high-speed vehicles under non-line-of-sight propagation

When a high-speed vehicle (HSV) is under emergencies such as instability, out of control, etc., a space TT&C system may face the problem that TT&C antennas in ground stations cannot continuously track and align the HSV, which causes the interruption of TT&C communication links and finally fails to transmit safety-control command and telecommand. In order to maintain TT&C communication links with ground stations when a HSV is instability, out of control, and non-line-of-sight (NLOS) propagation, it is proposed to apply shortwave communications to HSV TT&C system as an emergency communication method. Therefore, a flight experiment of NLOS shortwave propagation was conducted on a HSV. In the experiment, a ground station emits shortwave at 7 MHz, and the shortwave signal is received by a magnetic field meter that is installed inside the HSV. The magnetic field intensity of the received shortwave and background noise in fight environment are obtained. The experimental results show that as the altitude of the HSV increases, the magnetic field intensity decreases, and the HSV can always receive the shortwave signal in the case of NLOS and of antenna misalignment, which experimentally verified the viability of this method. This is the technical base of maintaining communications of HSV in long distance, beyond the horizon, and denied environments, and also provides important data to develop shortwave emergency communication systems for HSVs.