That's interesting. Do you have any idea how the different positioning system satellites are distributed? I'm reading you as saying there are less GPS-specifically satellites over Eurasia, whereas in the America's, there are less Golnass satellites flying over head. Does that mean, for example, that in Eastern Europe, your device has to wait for a shallower angle of free space to fine a GPS-type satellite that's closer to the horizon, since there just aren't that many GPS-types higher in the sky?
I do, the GPs sats are "bisas" the the equator, so when you are at about 50 degrees north or south, then you have the sats mostly toward the equator form you, they do get over head, but you will not see them toward the poles. then , as you get near the pole you start to "see" over the fpole to teh sats on the far side. (keep in mind taht the sat orbit at about 18 000 KM, or 3 times the radis of the earth).
now Galileo is in a higher inclined orbit, . so it reaches better to the northern areas.
If I remember correctly the GPS and gallileo are effectively circular orbits.
Glonass on the other hand (the russian system) I think is in a highly elpicial orbit, it fly in close over the earth on th e"far" side of Russia, and then swings WAY out over russia. The benifit of this is that IN Russia, the satlites are in view for a longer time, and once the leave teh sky in Russia, the whip around real fast to the other side to make their slow crossing of the sky again.
Keep in mind that the best position is given when you are SUROUNDED by satilites, . so if you have no sats to the north or south of you (either because they are not there, or because they are blocked, prehaps by a building, or hills, or the earth itself), then your north-south position is poor. Similarity if you have no satellites in the east-west direction, you have poor east west positioning.Lastly, if you have no satliles above you your hieight position is bad, - now because , the Signals can't go THOUGH the earth, you will never really have satilites below you (how ever, I guess if you where on the space shuttle...), because - at best you will only have sats above you , but not below you, you vertical measuement is always worse then your horizontal., typically by about 1.5 to 2 times.