Integration with external GPS // Bluetooth GPS Provider

[Tim Howard]

Hi all,

I'm exploring how I can use Geopaparazzi with an external GPS antenna, connected through an app like Bluetooth GPS Provider. 

https://play.google.com/store/apps/details?id=de.mobilej.btgps&hl=en

There are a few reasons why someone might want to use an external GPS rather than the internal one:

1. external antennas often access the DGPS satellites (WAAS in US, EGNOS in EU), resulting in higher accuracy

2. my understanding is that a bluetooth connection uses a lot less power than the internal GPS, so the batteries on the phone/unit may last much longer. 

3. If collecting data at a single point I can put the antenna down to hone in on the location (position average) while walking around with the unit collecting other data.

There are a few apps out there and the standard way to make it work is to pass the location through mock locations. 

Bluetooth GPS Provider can work without mock locations turned on if you root your phone and use it as an Xposed module. I have done this and this is the result:

-with mock locations off but Bluetooth GPS Provider running, Geopap does not think there is GPS signal. On the Geopap map, no blue GPS icon appears BUT, if I press the gps button (bottom center), the map will recenter at the proper location (sent from Bluetooth GPS provider). If I go to GPS Status & Toolbox, the X and Y coordinates, elevation, and DOP/HDOP/VDOP, and accuracy are all displayed (sent from Bluetooth GPS provider). Number of satellites, satellite positions, and satellite strength are not displayed. 

It looks to me like Bluetooth GPS Provider is not fully emulating the internal GPS (not yet!), but it also looks like there may be some issues on this side as well. I've tried to begin a discussion with the owner of Bluetooth GPS Provider, but I thought it might be useful to discuss what I'm trying to do here as well to see if anyone had any ideas. I'm most curious why Geopaparazzi will recenter to the GPS location, but will not display the blue GPS icon. Very strange to me. 

Thanks,

Tim

[Eli Adam]

On Thu, Jul 17, 2014 at 7:14 AM, Tim Howard <tgho...@gmail.com> wrote:
> Hi all,
> I'm exploring how I can use Geopaparazzi with an external GPS antenna,
> connected through an app like Bluetooth GPS Provider.
>
> https://play.google.com/store/apps/details?id=de.mobilej.btgps&hl=en
>
> There are a few reasons why someone might want to use an external GPS rather
> than the internal one:
> 1. external antennas often access the DGPS satellites (WAAS in US, EGNOS in
> EU), resulting in higher accuracy
> 2. my understanding is that a bluetooth connection uses a lot less power
> than the internal GPS, so the batteries on the phone/unit may last much
> longer.
> 3. If collecting data at a single point I can put the antenna down to hone
> in on the location (position average) while walking around with the unit
> collecting other data.
>
> There are a few apps out there and the standard way to make it work is to
> pass the location through mock locations.
>
> Bluetooth GPS Provider can work without mock locations turned on if you root
> your phone and use it as an Xposed module. I have done this and this is the
> result:
>
> -with mock locations off but Bluetooth GPS Provider running, Geopap does not
> think there is GPS signal. On the Geopap map, no blue GPS icon appears BUT,
> if I press the gps button (bottom center), the map will recenter at the
> proper location (sent from Bluetooth GPS provider). If I go to GPS Status &

I have on occasion seen something like this with internal GPS. GPS
appears to be working just fine but there is some display issue that
causes the blue dot to not show. I've always been able to get the
blue dot by maybe closing the map to go back to the main screen and
then reopening the map. It is infrequent and unpredictable enough
that I've not brought it up since troubleshooting seems difficult.
I've found no way to replicate this.

Other than no blue dot is there any indication that Geopap does not
think there is a GPS signal? If you turn on GPS logs and display
them, does it show properly? The situation I experience I would
phrase as, "Geopap thinks there is a GPS signal and functions
accordingly, however, for some reason the blue dot does not display."

Eli

> Toolbox, the X and Y coordinates, elevation, and DOP/HDOP/VDOP, and accuracy
> are all displayed (sent from Bluetooth GPS provider). Number of satellites,
> satellite positions, and satellite strength are not displayed.
>
> It looks to me like Bluetooth GPS Provider is not fully emulating the
> internal GPS (not yet!), but it also looks like there may be some issues on
> this side as well. I've tried to begin a discussion with the owner of
> Bluetooth GPS Provider, but I thought it might be useful to discuss what I'm
> trying to do here as well to see if anyone had any ideas. I'm most curious
> why Geopaparazzi will recenter to the GPS location, but will not display the
> blue GPS icon. Very strange to me.
>
> Thanks,
> Tim
>

> --
> You received this message because you are subscribed to the Google Groups
> "geopaparazzi-devel" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to geopaparazzi-de...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.

[Tim Howard]

I have on occasion seen something like this with internal GPS.  GPS
appears to be working just fine but there is some display issue that
causes the blue dot to not show.  I've always been able to get the
blue dot by maybe closing the map to go back to the main screen and
then reopening the map.  It is infrequent and unpredictable enough
that I've not brought it up since troubleshooting seems difficult.
I've found no way to replicate this.

Other than no blue dot is there any indication that Geopap does not
think there is a GPS signal?  If you turn on GPS logs and display
them, does it show properly?  The situation I experience I would
phrase as, "Geopap thinks there is a GPS signal and functions
accordingly, however, for some reason the blue dot does not display."

Eli

Eli,

Interesting, I'll look into that and see if that's the pattern I was experiencing. 

Thanks,

Tim

 

[Tim Howard]

Well, unfortunately, this is not what I'm seeing. All other GPS functions (tracks, auto-center, notes) all respond like Geopaparazzi doesn't think GPS has a fix. Yet the 'center on GPS' button continues to work. I'll try to look into it in more depth this weekend.
Tim