Galmon reveals fun stuff including the horizon around each receiver. I don't have the link handy, but one of the contributors was plotting "where in the sky a g

Galmon reveals fun stuff including the horizon around each receiver. I don't have the link handy, but one of the contributors was plotting "where in the sky a given receiver has ever seen a satellite", and it's plain to see which ones are next to mountains and stuff, because the outline of the mountains is vividly traced on the horizon. However, that's all long-term stuff. Moment to moment, GNSS receivers try very hard to mask momentary blips in data. I think you'd need to be down at the RF/baseband level to see the stuff you're trying to see, rather than taking "cooked" data from the receivers. The SDR GPS receiver in the KiwiSDR may be a good start.