How to Get Data From nRF9160 DK From GPS Example ?

[jaydip kavaiya]

Hi All

                   I am using nRF9160 DK version 0.8.5, and I have gone through this link, downloaded and Installed all the steps, given there.
All seems to be running good.

                   But some how, while retrieving GPS location, I am having some issues.

                   I am using the example code given in "Nordic_SDK\ncs\nrf\samples\nrf9160\GPS" I added the 'gps_data' structure in to watch

window & monitoring gps_data.pvt structure to get coordinates.

                   Some how, it shows Longitude = 1.22042e-76 and Latitude = 1.39737e-76.

                   It seems to be some garbage values.

                   Can you guys help me to fix this ?

 NOTE: I haven't inserted SIM card while using this example. Hope, it doesn't affect GPS functionalities.

Thank You,

[Hoang]

Hi jaydip kavaiya

Are you using: ncs_v1.0.0  fw-nrfconnect-nrf/samples/nrf9160/gps

It has fuction: link herhttps://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/samples/nrf9160/gps/src/main.c#L189

 

static void print_pvt_data(nrf_gnss_data_frame_t *pvt_data)

    printf("Longitude:  %f\n", pvt_data->pvt.longitude);
	printf("Latitude:   %f\n", pvt_data->pvt.latitude);
	printf("Altitude:   %f\n", pvt_data->pvt.altitude);

Can you share the log file

BR, 

Hoang Nguyen

[Hoang]

I just tried to remove the SIMCARD, and run gps example, it works normal:

Scanning [-] [1B][1;1H[1B][2JTracking: 8 Using: 8 Unhealthy: 0
Seconds since last fix 24

Scanning [\] [1B][1;1H[1B][2JTracking: 8 Using: 8 Unhealthy: 0
Seconds since last fix 24

Scanning [|] [1B][1;1H[1B][2JTracking: 8 Using: 8 Unhealthy: 0
Seconds since last fix 0
---------------------------------
Longitude:  10.484802

Latitude:   59.407666

Altitude:   61.914219

Speed:      0.806577

Heading:    0.000000

Date:       22-08-2019
Time (UTC): 11:15:30

[jaydip kavaiya]

Hi Hoang,

Thanks for your valuable reply.

With your suggestion, now I can get GPS data in Link monitor app.
But it takes about 300 to 500 seconds to get 1st GPS data after power up.

Is this delay reasonable, after power reset?
Do we need to wait for such long time, if we want GPS data after waking up from sleep ?

If we add 'gps_data.pvt' structure in watch window, it shows the values mentioned in the main thread. Please help me here, also.

[Bjørn Kvaale]

Have you placed the DK near a window? Are you using an external GPS antenna? Have you taken a look at the prj.conf settings? You are able to change some of the values if needed, but I would suggest to leave them as be first. 300 to 500 seconds seems like you are testing inside without an external antenna.

[jaydip kavaiya]

Hi Bjorn Kvaale 

Yes, We have placed the DK near window & we are not using any external antenna.
We haven't changed the prj.conf settings.
You are right. I think this delay is because of the placement of device, near window area.
I'll test it under open sky & let you know, if there is some unknown behavior.

Bjorn Kvaale, can you guide me why I am getting 1.22042e-76 like values for GPS data, if I monitor 'gps_data.pvt' structure, using debug session?

[Hoang]

jaydip kavaiya

can you share the log file, I really want to see it to understand more about your case.

thanks, 

BR, 

[jaydip kavaiya]

Hi Hoang

Sure This is my logfile

2019-08-27T10_37_27.545Z-log.txt

[Hoang]

Hi jaydip kavaiya, 

I see the pvt_data data is normal, 

i can find your position: 

https://www.google.com/maps/place/23°01'07.7"N+72°32'39.0"E/@23.0188149,72.5419893,17z/data=!3m1!4b1!4m5!3m4!1s0x0:0x0!8m2!3d23.01881!4d72.544178

from your log file:

2019-08-27T10:40:50.839Z DEBUG modem << Longitude:  72.544178\x0D\x0D\x0A
2019-08-27T10:40:50.843Z DEBUG modem << Latitude:   23.018810\x0D\x0D\x0A
2019-08-27T10:40:50.845Z DEBUG modem << Altitude:   2.559669\x0D\x0D\x0A
2019-08-27T10:40:50.848Z DEBUG modem << Speed:      0.551426\x0D\x0D\x0A
2019-08-27T10:40:50.892Z DEBUG modem << Heading:    0.000000\x0D\x0D\x0A
2019-08-27T10:40:50.894Z DEBUG modem << Date:       27-08-2019\x0D\x0A
2019-08-27T10:40:50.896Z DEBUG modem << Time (UTC): 10:40:53\x0D\x0A\x0D\x0A

I didnt see 1.22042e-76 on your log file. 

Is it correct?

BR, 

Hoang Nguyen