Hi - Thanks for replying but that doesn't address the question.
There are two common methods by which speed can be calculated using GPS;
1) Using the doppler shift
2) Calculating the distance between to points and the time taken to travel between them.
The codec protocols don't say which method is used, just the it's calculated using GPS (both of the above fit that statement).
Can Teltonika please confirm which of the methods is used, and support this with some form of documentation eg the tech sheet for the GPS chip.