T121-M数字无绝缘轨道电路
TI21-M digital jointless track circuit
无绝缘轨道电路
Non-insulation Track Circuit
jointless track circuit
track circuit without insulating
Non-insulated Track Circuit
赤道轨道卫星
satellite equatorial orbit
接近同步赤道轨道
near synchronous equatorial orbit
近同步赤道轨道
near synchronous equatorial
orbit
双轨轨道回路
double rail track circuit
同步赤道轨道
synchronous equatorial orbit