The precision is in cm, so HORIZ PRE will be 5e8 or 500000000cm = 5000km and VERT PRE is more likely to be around 1e5 or 100000cm = 1km although I'm not sure ab

The precision is in cm, so HORIZ PRE will be 5e8 or 500000000cm = 5000km and VERT PRE is more likely to be around 1e5 or 100000cm = 1km although I'm not sure about this value - maybe 5km or 5e5 would better account for the height variation in the US?