Calculate GPS accuracy in meters

RE: Calculate GPS accuracy in meters

Heidi — Mon, 31 Aug 2020 07:07:27 GMT

Hi, yes you're correct.

The accuracy field of the PVT notification gives an estimated standard deviation for the fix accuracy, so if the accuracy field is e.g. 5, the fix is estimated to be within 5 meters with 67% probability.

Best regards,

Heidi

RE: Calculate GPS accuracy in meters

Chris Burns — Fri, 28 Aug 2020 16:32:21 GMT

Apparently the information I was looking for is already in the PVT notification. It's the accuracy field and the comment in nrf_socket.h is:

float accuracy; /**< Accuracy (2D 1-sigma) in meters. */

So that field will give the accuracy to within one standard deviation.

RE: Calculate GPS accuracy in meters

Chris Burns — Thu, 27 Aug 2020 20:45:29 GMT

I think I need to clarify what I meant. I'm looking for a way to know the possible error in the latitude and longitude given by the GPS when it gets a fix.

For example, when the NRF_GNSS_PVT_FLAG_FIX_VALID_BIT is set, is there a calculation that tell what the accuracy is (like this fix is within 5 meters or within 3 meters)?

RE: Calculate GPS accuracy in meters

Heidi — Thu, 27 Aug 2020 13:46:15 GMT

Hi!

According to the GPS Elspecs, the accuracy of the GPS is between 3 - 5 meters. So the application could compare the coordinates from a GPS fix and the specific coordinates you want to investigate.

It doesn't look like we have anything like this already programmed in NCS, so you would have to implement it yourself. To learn more about calculating the distance between two coordinates, take a look at this page or this page.

Best regards,

Heidi