GPS antenna - signal noise

I just noticed while experimenting indoors with my NAVIO+ board . the gps signals was poor even with the antenna placed with full cable length away from the raspberry.( as expected indoors) To try to get better signals, I found a small metal box and placed the antenna on top of it and the signals got better. Since the raspberry with the navio+ board was on the floor beside me and to avoid accidentally damage the board, I then placed the metal box over the raspberry/ navio+ with the antenna on top and noticed that the signal strength of the gps then was significantly better. To me the reason seems to be noise from the raspberry/navio+ board disturbing the gps signals and when the metal box is placed over the raspberry/navio+ , the noise is suppressed so that the gps get a better reception. The difference was quite significant so I wonder if anyone has noticed this, and if so any tips to avoid this without the large metal box,


This is quite a common issue. The best way to avoid it is to have the gps antenna as far away as possible from any RF sources, these will be in order of strength motors, ESCs, BECs, Navio.

Many designs uses masts to keeps it far away. Your metal box is a Faraday cage of sorts.