GPS Accuracy measurement | Thales IoT Developer Community
February 1, 2018 - 10:20am, 2098 views
I have PHS8-US and PLS8-X Gemalto modem. I would like to know GPS accuracy runtime. Is there any way to get GPS accuracy from GPS string or any calculation?
Hello,
When you activate GPS receiver you get NMEA data and you can try to calculate/estimate the accuracy based on that data.
In GPGGA there is a parameter DOP (dilution of precision). It is a unitless number where smaller is better. For 3D fixes using 4 satellites a 1.0 would be considered to be a perfect number.
In GPGSA there are 3 parameters: PDOP (dilution of precision), HDOP (Horizontal dilution of precision) and VDOP (Vertical dilution of precision).
Regards,
Bartłomiej
And how we can use PDOP, HDOP, VDOP for accuracy measurement?
It is not so easy to estimate the current accuracy in meters (if that's what you need) from these parameters.
You probably have visited these or similar links:
https://en.wikipedia.org/wiki/Dilution_of_precision_(navigation)
https://wiki.openstreetmap.org/wiki/Accuracy_of_GPS_data
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_...
Please also see this NMEA sentences - PCWMV, which is a proprietary Gemalto NMEA sentence. You can find it in the AT commands specification document. It is only active when Dead Reckoning is activated.