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GPS sensor rate - only 1 per 20 sec - Printable Version

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GPS sensor rate - only 1 per 20 sec - gneiss - 10-27-2020

Hello!

First of all, thank you, developers, for this amazing and well-built app!

I am writing because I noticed a peculiarity about the Location sensor. The rate at which my phone takes GPS/Location readings is only 1 reading per 20 seconds. This is an obvious limitation for location based experiments. Since I have not seen any post or info regarding this (and I believe a lot of people would notice the limitation), I suppose the problem could lie in my phone's settings, but I cannot find it. This measurement rate is even output in the exported .csv files. I have also tried creating a new experiment where I combine sensor readings and change the measurement rate, but to no avail.
Is this a known problem or a limitation of the app? And is there a solution?

I would like to create an experiment where I measure the vibrations created by the city tram and correlate them with building deformations. This requires a very fast accelerometer refresh rate and reasonably fast GPS measurement rate.

Thank you in advance!


RE: GPS sensor rate - only 1 per 20 sec - Jens Noritzsch - 10-27-2020

The rate of the location “sensor” is set by the OS and there is no way to get more frequent data. Such a low number of readings is unusual though. There might be issues with the GPS signal reception (or the other means in finding a location), inside buildings, for instance, – or trams.

From time to time, I experience these on trains and particularly on Android. Note that iDevices do not necessarily utilize GPS, so it could appear that they handle these situations better than Android devices with GPS enforced.


RE: GPS sensor rate - only 1 per 20 sec - gneiss - 10-27-2020

(10-27-2020, 09:56 PM)Jens Noritzsch Wrote: The rate of the location “sensor” is set by the OS and there is no way to get more frequent data. Such a low number of readings is unusual though. There might be issues with the GPS signal reception (or the other means in finding a location), inside buildings, for instance, – or trams.

From time to time, I experience these on trains and particularly on Android. Note that iDevices do not necessarily utilize GPS, so it could appear that they handle these situations better than Android devices with GPS enforced.

It seems that the problem is not with the OS (forgot to mention I am using Android on Samsung S7 Active) but more likely the Phyphox app, because other navigation apps do take measurements at least once a second and probably even faster. The reception also was fine since the other apps worked correctly.

For now I am trying to run both Phyphox and a navigation app that tracks my location simultaneously. It is less than ideal as I have to count out the seconds passed after I have turned on the tracking, then switch the apps and start collecting accelerometer data. The precision is +/- 1 second and data from two different sources takes longer to process.

Still looking for a solution!


RE: GPS sensor rate - only 1 per 20 sec - Jens Noritzsch - 10-28-2020

(10-27-2020, 10:51 PM)gneiss Wrote: It seems that the problem is not with the OS (forgot to mention I am using Android on Samsung S7 Active) but more likely the Phyphox app, […]
Could you provide us with the OS and phyphox version. Do you enforce the use of GPS satellites in phyphox? What are the OS Settings in Privacy & Safety > Location? Could you reproduce the low rate with the dedicated Location/GPS experiment?

Quote:[…] because other navigation apps do take measurements at least once a second and probably even faster. The reception also was fine since the other apps worked correctly.
A higher rate than 1Hz is rather unlikely as GPS quite drains the battery, which is prevented in smartphones as much as possible. Also we cannot judge if your other navigation apps use some extrapolation algorithm to “assume” a position. I take it as granted that you have tested phyphox against other navigation app on the same track…

There is simply no setting in the API to speed up the readings, just to slow these down – that we don't.


RE: GPS sensor rate - only 1 per 20 sec - gneiss - 10-29-2020

Well, it just so happens that Phyphox is updating my Location every second. I am not sure what happened - what settings did I change or whether there was a glitch in OS or the app. Though, as usually in situations like these, it probably was a user error of some sorts. Smile
Thank you for helping, anyway, Jens!


RE: GPS sensor rate - only 1 per 20 sec - Jens Noritzsch - 10-29-2020

That's good news, thank you for keeping on trying.