How does the VBOX still work whilst going under a bridge ?
Amost all GPS systems cannot work under bridges. When a vehicle passes beneath a bridge, the bridge wipes across the antenna’s view of the sky over short period of time. This means lock is broken and then re-made on each satellite in view. However, we have spent considerable time optimising the settings and firmware on the GPS engine we use to regain lock on a satellite instantly it comes back into view, (as long as other satellites are in lock). Therefore, as you pass under the bridge, you lose around 1 or two satellites out of the total, but at all times there still should be enough sky in view to continue calculating velocity and position. The VBOX will work under any bridge, even a large motorway type bridge has enough sky visible to remain locked on to some satellites. Absolutely no guesswork is involved, no interpolation or heavy filtering is used. You can always see some sky whilst travelling under a bridge, (if you can’t you are in a tunnel, where it definately won’t work) the
