Hallo,

es kam gestern die Frage nach der Konvertierung der Byte-Reihenfolgen. Bei mir liefert

$ man htonl

alles Wissenswerte.

Zum Thema Dopplerverschiebung von GPS habe ich unter http://www.racelogic.co.uk/vbox/gps.htm folgendes gefunden, was sich mit meinem bisherigen Wissen deckt:

In hand held recreational GPS receivers, the velocity is calculated once a second by taking the current position and subtracting the previous position. This method of calculating velocity is subject to these same errors, making the result unsuitable for accurate analysis.

The VBOX uses the Doppler shift in the carrier signals coming from each satellite, in the same way a radar gun is used to measure speed.

The carrier frequency is unaffected by ionosphere effects and reflections, and this means the resultant speed is accurate to a centimeter per second, which now makes GPS one of the most accurate way of measuring velocity of a moving vehicle.

Torsten