DOP

[Domel]

Hi

I am performing a receiver test where my location is a few meters offset from the actual position. Looking at the diagnostic I can see that my DOP's are below 1 however VDOP is around 4.
Can vertical dilution issue cause the incorrect lat/long position?

Thanks

[GPSrChive]

Basic answer to your question is no.

Vertical precision using GNSS is always less accurate than horizontal position accuracy.

How do you know your receivers actual position?

[Domel]

.kml file as a layer on Google Earth....if that is reliable

[GPSrChive]

That most certainly is not reliable.

Where are you located?

Do you have any benchmarks nearby?

[Domel]

I'm in Gloucestershire, UK.
I can see one nearby on the surveying map.

I suspect the device is not that great as every time I turn the GPS logger on it is away from my "fixed" location by up to 5 m in various directions. Lat/long.

I'm not worried about altitude, I was curious if poor VDOP would affect it.
I'm using Quectel SC200E

[GPSrChive]

I would recommend testing accuracy at that location, averaging multiple samples over many days.

You can also use a GNSS Prediction service to find the best days and times for testing.

See GPSrChive > GNSS > Satellite Prediction