Questions and discussion about the geolocalization features of the TD RF modules.
Posts: 11
Joined: Mon Jul 04, 2016 11:34 am

GPS Precision

by gertorro Wed Aug 17, 2016 8:55 am

it seems that I'm having an important and consistent shift in the position measured by the GPS.
I've forced it to have a 3D fix with a horizontal accuracy smaller than 60 m and the coordinates that I'm getting back do not correspond with my actual location (about 10 km error).
I have a question, does the GPS data come in standard WGS84 reference system? If I have correctly interpreted it, where does this error come from?

EDITED: I've used the u-center in order to check the GPS directly, it seems to work perfectly, the problem is in my software or in the libraries not parsing correctly the GPS data. I'm using a TD1204EVB with an external active antenna.

EDITED 2: To check, I've loaded the example "geoloc_fix" and it also presents the same error as my code. Can anybody replicate this error? :!:

Posts: 2
Joined: Thu May 25, 2017 10:12 am

Re: GPS Precision

by Quim Thu May 25, 2017 10:40 am

Hi, we have the same problem with our TDS1205P. After we sent an AT$GPS=1,16,0,65535,1,1 command, we receive the following position: Lat 41.1342038 Lng 1.4413741

After one minute:

After five minutes:

but our position is some kms far away from that point: Lat 41.223204 Lng 1.735459

is there any configuration we can fix, please?

On the other hand, we are able to send the position to the Sigfox backend with AT$GSND, but we don't find how the position is encoded in the sifgox frame. We receive the following data frame by email, or URL encoded... but how extract the position?

"data": “0201010014facdb8b7a02c1c",

Also, can we use AT commands to send periodically the GPS position to the network? as a keepalive message? My desire is to send a keepalive message every hour with the GPS position inside the "data frame".

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Posts: 168
Joined: Thu May 07, 2015 9:24 am

Re: GPS Precision

by mstempin Fri Jun 02, 2017 7:11 am

Please check this thread:
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