PowerSave mode

[PumpkinEater]

Hi,
I am using GSM TRacker on my Nokia E71 phone and I am very happy with all the functions and the stability of the application.
Not a large point, but I am a little bit confused about the powersave settings. The documentation describes, that the parameter "GPS / Retry after" should be set larger than the parameter "Time period, min". For example, if I set "GPS / Retry after" to 10 and "Time period, min" to 2, I will get values only each 10 minutes (because the GPS is woken up then), but not each 2 minutes as I tried to set with parameter "Time period, min". So, what is the use of parameter "Time period, min" in this case. Does it matter, whether I set it to 1,2,3 ..9 minutes?

Other question: Is there a minimal value for "GPS / Retry after"? Ok, I understand, that the power saving will be smaller, but is there a time (e.g. 1 min), where the GPS isn't switched off anymore?

Thank you and best regards,
Peter

[jje]

The documentation describes, that the parameter "GPS / Retry after" should be set larger than the parameter "Time period, min". For example, if I set "GPS / Retry after" to 10 and "Time period, min" to 2, I will get values only each 10 minutes (because the GPS is woken up then), but not each 2 minutes as I tried to set with parameter "Time period, min". So, what is the use of parameter "Time period, min" in this case. Does it matter, whether I set it to 1,2,3 ..9 minutes?

It does not matter, whether you set "Time period, min" to 1,2,3 ..9 minutes, when you are using the GPS powersave feature and you have set "GPS / Retry after" to 10.

All the values 1,2,3 ..9 should cause the same result (at least with the latest version of our software, v3.19).

Is there a minimal value for "GPS / Retry after"? Ok, I understand, that the power saving will be smaller, but is there a time (e.g. 1 min), where the GPS isn't switched off anymore?

The minimal effective value is 1 minute. It does not cause much power saving, though. In contrary, it might cause even more power consumption due to frequent supl.nokia.com traffic, if you are using AGPS. I would recommend to use at least 5 minutes value, if you enable the GPS powersave feature and really want to save some energy.

Thanks for the good questions!

Jyrki

[PumpkinEater]

Hi Jyrki,
thank you for your quick reply. I have set the retry now to 5 min, which gives good results as long as I am moving slowly. But on car the track is too rough (this was already discussed in the thread "power save after fix :On, but when moving?" last year). My idea is to use cell changes to wake up the GPS from power saving mode. Ok, this pretty much depends on the cell size, but in urban regions the cell size could be small enough while in rural regions the speed might be higher (which then would compensate the larger cell sizes). But as I said: just an idea for discussion.

Thanks,
Peter

[jje]

But on car the track is too rough (this was already discussed in the thread "power save after fix :On, but when moving?" last year). My idea is to use cell changes to wake up the GPS from power saving mode. Ok, this pretty much depends on the cell size, but in urban regions the cell size could be small enough while in rural regions the speed might be higher (which then would compensate the larger cell sizes).

Hi Peter,

Thanks again for your good idea. I do not yet promise to implement it but we surely consider it. I put some of my thoughts below.


The cell is often changing also when the handset is stationary. This does not mean that your idea would not work.


If we used cell changes to wake up the GPS, that would effectively mean that the GPS chip would be constantly powered up, when you are driving. It would reduce the battery time during long drives.

The power consumption is rather high, if you want to do real time tracking while driving. Both the GPS and 3G radio are power hogs, when in use.

Would a reduced battery time still be tolerable?


We instruct our customers to use a car charger when they are driving. If the handset is connected to a charger, the power saving feature of Aspicore GSM Tracker is disabled and the GPS power stays constantly on.

If you adopt the habit to put your phone in a car charger every time you are driving, you get exact and accurate tracks of all your driving trips (except tunnels etc.) even with the current version of GSM Tracker.

Do you think it is impractical to use a car charger?

(If you are travelling by public transport, you cannot use a car charger, of course.)


The cell change based GPS wake up would work without a car charger, but the exact beginning of the trip would easily be lost, because the cell probably changes only after driving couple of hundreds of meters.


We'll think about your idea. It is technically very possible and quite straightforward to implement. It would probably mean adding one new settings item to the application. Would it make the app better and easier to use or the contrary?


- Jyrki

[PumpkinEater]

Hi Jyrki,

If we used cell changes to wake up the GPS, that would effectively mean that the GPS chip would be constantly powered up, when you are driving. It would reduce the battery time during long drives.

Right, that could be a problem (example: 50 km/h -> 833 Meter/min -> cell changes every 1,2,3 minutes depending on cell size). But in that case the wakeup frequency could be limited (minimal wakeup interval), so that some cell changes are skipped away. But anyway, this could be a way to tune the number of tracking events based on speed without measuring the speed by GPS but on cell changes. To figure out whether this functionality is senseful one would have to do some tests with a beta version.

The use of a car charger is useful for longer trips, but I don't use it for short ways through the town or trips under 1 hour. But of course, it is very good to know, that powersafe mode is switched off during charging.

We'll think about your idea. It is technically very possible and quite straightforward to implement. It would probably mean adding one new settings item to the application. Would it make the app better and easier to use or the contrary?

Yes, a lot of settings might confusing the user (I also needed some time tpo understand all the parameter). One soulution could be to put those special settings into a extra menu point "advanced settings" so that normal users don't need to think about.

Thank you and best regards,
Peter

[robino]

Hi

I am actually looking for the exact same feature

I am trying to make myself a rather cheap vehicle tracking unit for my cargo bike to avoid theft. Since there is no power avaiable I am building a battery into the bike. However, in order to not have to charge it all the time I need the tracking to be low power.

Most of the time the bike is not moving. And therefore a feature where the GPS is not activated (or activated very seldom) when not moving will be crucial. As soon as movement is registered e.g., by cell change, positions should be sent frequently for some time. Since I am living in urban area (it is probably only in urban areas that bikes are stolen) it would be nice to be able to cfg e.g., 2 cell chages before activating GPS, thereby reducing the number of false movement detections.

When it is moving, I need to have frequently fixes in order to be sure to get a good location just before it is put inside some shelter.

I am currently trying to find out which product to use, so an indication of whether I can get such this power save feature in Aspicore product would be nice.

Best regards

Robin