On Friday, April 6, 2012 8:47:03 AM UTC+10, StarTraX wrote: > > Hey Sean, > Thanks for your post. Seems like there is some intelligence out there > after all! > I tried to follow your links but hit an Office Outlook web access login > page, so couldn't progress. Is that me or is there a way through? > > When you refer to "the GPS provider", I wonder what component you are > actually referring to? Could you direct me to some more reading on "...GPS > provider has two built-in scheduling modes..." > At the hardware layer, on my SGS11, the PVT data is provided by the CSR > SiRF chip, whose data page talks about the "host SDK" providing most of the > interface stuff. I have written to CSR to get some user specs on this > software, but have not made much progress to date. My guess is that the > implementation of the response to the requestLocationUpdates minTime call > is implemented by Samsung using that SDK. > > In an earlier versions of my code, I have seen my NMEA location listener > event being raised far less frequently than 1 Hz, in a pattern that > indicated some interaction with my speed and route - at highway speeds, in > a straight(ish) direction, it was firing at around 10 - 15 seconds. > Unfortunately I can't reproduce that behaviour (at that time I was wanting > exactly 1Hz response, so binned the code and started again!). > Now I desperately want to return to that behaviour, but can't reproduce it! > > > > On Thursday, March 29, 2012 2:22:02 AM UTC+11, Sean Barbeau wrote: >> >> Hi all, >> I've been working with the Android platform code lately, and had a chance >> to look at this issue of the GPS provider ignoring the minTime parameter on >> a number of devices more in depth. The GPS provider has two built-in >> scheduling modes, native and platform, that are designed to follow the >> minTime parameter, so the problem isn't lack of capability in Android. >> >> After some research, I believe the issue stems from native code reporting >> that it can handle GPS refresh scheduling, but then the native code doesn't >> actually do the scheduling, effectively preventing the Android platform >> from properly handling the scheduling. I posted a more detailed >> description about this issue in the Android Contributors group: >> * >> https://groups.google.com/forum/?fromgroups#!topic/android-contrib/KCE_ZNLsyLQ >> *<https://groups.google.com/forum/?fromgroups#!topic/android-contrib/KCE_ZNLsyLQ> >> >> I submitted a patch to the Android project (still under review) that >> essentially implements a fail-safe switch as a workaround for this problem, >> so the developer can force the Android platform to properly handle the GPS >> refresh scheduling if the native code isn't working properly: >> *https://android-review.googlesource.com/#/c/34230/*<https://android-review.googlesource.com/#/c/34230/> >> >> I've tested this patch on a custom Android build on a Nexus S 4G, and it >> works. Without the patch, the Nexus S 4G just spits out locations at 1Hz >> no matter what you set the minTime parameter to. >> >> If this issue has affected you as an Android developer and you'd like to >> see this patch make its way into Ice Cream Sandwich for all future Android >> device updates, I would suggest voicing your support by replying to my post >> on the Android Contributors list. It would help if you mention the make >> and model of the device that has the problem as well, so we can track which >> phones are currently affected. >> >> I haven't gotten much response about this from Google yet, but hopefully >> if they see this is an issue that is important to developers they would be >> willing to accept this patch. If the patch is accepted, it would provide a >> fail-safe method for developers on all future Android devices to ensure >> that GPS scheduling performs as intended from the application's perspective. >> >> Thanks, >> Sean >> >> Sean Barbeau >> Center for Urban Transportation Research >> University of South Florida >> >
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