I just bought a phantome 3 SE, flew few time, i am living in pungol, it is no problem when i play out side the open field, but if i wanna try fly in my home or just garden downstairs, the GPS sinal is always low, and navigator can't calculated, i thought SE has the visual sensor, it should be able to work if gps signal weak?

I just bought a phantome 3 SE, flew few time, i am living in pungol, it is no problem when i play out side the open field, but if i wanna try fly in my home or just garden downstairs, the GPS sinal is always low, and navigator can't calculated, i thought SE has the visual sensor, it should be able to work if gps signal weak?