where such an altimeter is the official altitude recording device
That does not mean it is actually happening at a true 750ft.
So what will give you a "true" 750'?
QuoteThat does not mean it is actually happening at a true 750ft.So what will give you a "true" 750'?
The only thing I can think of to account for the 9m was that I was walking at a different time and so possibly triangulating with different satellites. I just looked up Garmin (it was not Garmin I was using) and they say their receivers are accurate to 15m on average. I was expecting 5-10m.
GPS units with 5 m accuracy might exist right now.
But it takes time to get the intentionally-introduced jitter out
Thus, you only find them in surveying gear that has very nice antennas and very pricey boxes to do the signal processing.