Accuracy of GPS

[safisafo]

Hi. I'm using the SIM7600E module to take my latitude and longitude, but the result given is located like 30km away (very bad accuracy, like 3º), but it doesn't almost change. I'm running it indoors, is this normal?

[topguy]

Can you link us a datasheet for the product you are using, because none of the modules with that name that turn up in Google actually have a GPS, its a 4G modem.

[bensimmo]

Something is wrong OR theit is the way you are reading the NMEA coordinates*.
It should get you within 10meters without a problem.. normally after a bit of time.

Apparently some models can have GPS.
https://www.waveshare.com/wiki/SIM7600E-H_4G_HAT


*There are different methods of representing coordinates.
But I should be degrees and minutes iirc
DDMM.MMMMM

Try http://www.hiddenvision.co.uk/ez/ to change to a different system and use that in your map.
Also if anything like the UK and you are sat in the meridian line then watch out for - E & W

[pfletch101]

Something is wrong OR theit is the way you are reading the NMEA coordinates*.
It should get you within 10meters without a problem.. normally after a bit of time.

I would not bet on this GPS accuracy (or even working at all) when run indoors, which the OP notes is his situation.

[bensimmo]

Something is wrong OR theit is the way you are reading the NMEA coordinates*.
It should get you within 10meters without a problem.. normally after a bit of time.

I would not bet on this GPS accuracy (or even working at all) when run indoors, which the OP notes is his situation.

If it gives coordinates then it has a lock on a few satellite. So it has a a good radius to work with, maybe not 10 meters, but within 100m no problem. NOT 30km's ...
which sound like a unit mix up on the mapping program.

[pfletch101]

Something is wrong OR theit is the way you are reading the NMEA coordinates*.
It should get you within 10meters without a problem.. normally after a bit of time.

I would not bet on this GPS accuracy (or even working at all) when run indoors, which the OP notes is his situation.

If it gives coordinates then it has a lock on a few satellite. So it has a a good radius to work with, maybe not 10 meters, but within 100m no problem. NOT 30km's ...
which sound like a unit mix up on the mapping program.

You may be right - if it is a GPS device. However, the OP also hasn't responded to topguy's implied question, noting (correctly) that the device the OP says he is using is a 4G modem with no GPS capabilities. Whatever he is using to get his location may be returning the location of the first router in his transmission path that admits to its location!

[drgeoff]

The SIM7600E module does have GPS capability

See https://simcom.ee/modules/lte/sim7600e/ . Under General features "GNSS gpsOne Gen 8B;standalone;assisted,XTRA"
See https://simcom.ee/documents/SIM7600E/SI ... 20V1.1.pdf pages 1 and 5 for mention of GNSS antenna

But does whatever the OP is using have a GPS antenna connected to the SIM7600E?

[bensimmo]

I posted a link to one, it has GNSS, aka GPS.

I doesn't mean it may not, but await to see.

EDIT , to above post, the Waveshare one is that chipset I linked to.
Also as it GNSS it has GLONASS, Beidou etc like my Ublox8. These connect indoors much better than my ublox6 which can fail to get a lock.

Anyway, back to await feedback.

[teohhc]

I am facing similar issue.

I've managed to get Raspberry Pi 4 working with Sim7600e similar to https://tutorial.cytron.io/2019/09/04/a ... 0e-module/

However, the GPS coordinates received seems to be 30km off.

There are 3 mode for the GPS session:

1. standalone
2. UE-Based
3. UE-Assisted

However, managed to only get mode 1 & 2 working and still yielding the same result of 30km off.

For the 3rd mode, I did the following:

1. AT+CGDCONT= 1,"IP","diginet","0.0.0.0",0,0
2. AT+CGPSURL="supl.google.com:7276" # set agps url
3. AT+CGPSSSL=0 # set security mode
4. AT+CGPS=1,3 # start gps in assisted mode

But it will fail.

I am trying to improve the accuracy of the GPS. Anyway that I can achieve this?

[teohhc]

I collected further data to understand the situation better.

Switched the SIM7600e and GPS antennas to another spare set but getting same result. Hence, faulty device is ruled out.

[teohhc]

Thank you. Solved.

The device is not the problem. Problem is knowing which part of the number needs decimal point shifting and the remainder needing to be in minutes. Lat and Long using similar formula but Lat needs 100 more.

[bensimmo]

glad you got it sorted, saved me having a look