Inductively-charged border-monitoring autonomous drones. UHV DC transmission lines [1] [1] http://www.economist.com/blogs/graphicdetail/2017/01/daily-chart-14

Inductively-charged border-monitoring autonomous drones. UHV DC transmission lines [1] [1] http://www.economist.com/blogs/graphicdetail/2017/01/daily-chart-14 http://www.economist.com/blogs/graphicdetail/2017/01/daily-c...