Comment on 3/2014: Navigation

[vleeuwen]

Thanks for the description of the maths behind GPS.

In the article I am missing some notes/references about the "accuracy" in a dynamic situation.
GPS devices need a certain time to obtain their minimum accuracy. And this is coming on top of the theoretical accuracy of the GPS system itself [reference 4].
When a GPS device is moving the accuracy will be more than 2 m (see the data sheets of the GPS device).
Practical between 5 to 15 meters. This makes GPS less suitable for use in small area's.

The 15 m (Die durchschnittliche Genauigkeit beträgt bei Consumergeräten etwa +- 15 m (bei "normalen" Bedingungen)) is also mention in [reference 4] and is not mention in the article.

[Dirk Fox]

Hi Carel,

many thanks for your feedback.

In the article I am missing some notes/references about the "accuracy" in a dynamic situation.

Specifying even the accuracy of a stationary GPS device is difficult, because it depends on several parameters (number of sattelites, reflections, angle of incidence, noise filtering etc.). You are right that the accuracy of the result decreases if the device is moving - but the additional inaccuracy heavily depends on speed, sensor frequency and the method of average determination. In my view it isn't reliable to quantify the accuracy in motion without exactly specifying these conditions.

But, to tell the truth: even the maximum speed of a fischertechnik robot does not significantly affect the result; this is why I omitted this aspect in my article.

Regards, Dirk