The transmission of the earth wave is stable, hardly influenced by climate and its channel parameter does not change with time basically, it is Constant Parameter Channel.
地波传播受天气的影响较小，比较稳定，信道参数基本上不随时间的变化而变化，是恒参信道。
2
Intelligent defrost, set defrost parameter according to different regional climate condition, defrosts thoroughly.
智能除霜，可根据不同地区气候条件设定除霜参数，除霜更彻底。
3
Based on a simple HVAC climate model, considered the effect of latitude, distributing of land and water, terrain and discrepancy on town and village, ascertained the parameter.