Can not get external GPS to work

[SROCMapper]

I've been trying to get external GPS to work on an Android phone. It all appears to work ok but when I "go to start" the red dot showing my location never appears. The display at the bottom of the screen is different too. It says : Sats: 12  GPS: 4.84m (for example) whereas using the phone's GPS it says GPS: 13.7m UNKNO 0.0km ( for example). Any ideas?

[Peter Effeney]

On the main run screen of MapRunF, we have three tabs. The one on the Right displays the string of messages coming from the GPS. This is to help identify any issues.

In the case where you have changed MapRunF's "GPS Input" to Bluetooth GPS, this tab will show the NMEA messages coming through via GPS. NMEA doesn't offer a numerical GPS accuracy measure (unlike the inbuilt Android location service), so we handle it differently and need to calculate our own from HDOP etc.

There are two ways to use a Bluetooth GPS with MapRunF... change the GPS input as mentioned above, but maybe a better way is to use a Bluetooth GPS companion App that manages the GPS and then creates "Mock" locations in Android. MapRunF will happily use these (with the "GPS Input" set to "Phone Input"). This approach has the advantage that often Bluetooth GPS Apps can give better control of, and reporting on, the Bluetooth GPS.

We have mappers who value the extra accuracy that Bluetooth GPS's can offer (eg multiple satellite constellations etc). It generally works well once you get over the setup challenges.

Let us know if you still have issues.
Peter

[SROCMapper]

Thanks for your reply. I can see the NMEA messages coming in from the external gps device on the log tab. As it all appears to be set up correctly I was hoping to avoid installing a separate app but I guess I will have to try that instead.

[Peter Effeney]

The key NMEA messages that MapRun is looking for are:

GNGGA or GPGGA - It extracts locations from either of these message types.

Otherwise try a BT GPS Companion App - it will likely give you more diagnostics...

Peter

[SROCMapper]

The external gps source has the right messages so far as I can see, screenshot :


I'm trying with "Bluetooth GPS" app now instead.