[Gta04-owner] GTA04A4 starts shipping tomorrow

Dr. H. Nikolaus Schaller hns at goldelico.com
Tue Jan 31 10:53:20 CET 2012


Am 31.01.2012 um 00:47 schrieb Lionel Broche:

> Good job, keep up with the good work!
> How does the GPS performs now, with the HW fix and internal antenae?

Much better than before. It is possible for an indoor situation to get time within
10 seconds and date within 20. And 3 or more satellites within 30-40 seconds.
In a cold start situation.

As soon as the receiver starts tracking and knows its position, it even increases
its sensitivity so that you can get 6-8 satellites.

Generally an external antenna is still better and I have seen it receiving and
using for navigation 11 of 12 possible satellites.

SNR values I have seen is in the 15-35 dB range (indoors) with internal
antenna and 25-45 with external. Getting a low TTFF needs 3 satellites
above approx. 28 dB. The receiver may track them down to approx. 15 dB
before loosing them. So it has a very wide dynamic range.

Of course there are still many factors influencing sensitivity. Just holding
your hand in 5-10 cm distance in the direction of the strongest satellites
may reduce the SNR by 5dB. And, heavy SD card activitiy is also still recognizable.
E.g. copying files may also reduce by 5dB while this is in progress.

But in my subjective impression it is better than randomly picked GTA02 (there
has been a wide variance between good and not so good devices).

Nikolaus



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