Is it possible to access the built-in GPS in the 7135 with a palm app? I've looked through the 7135 SDK, and there don't seem to be any GPS-related interfaces. Did I miss something?
I've seen a number of threads regarding using external GPS units with the 7135, which seems like a waste to me if the phone has GPS functionality built into it.
You believe correct! Just to reiterate stuff buried in the forum threads, the GPS that is built into the 7135 is not a standalone GPS. It is actually Assisted GPS (aGPS), that is it is assisted by the cell phone service provider. So if the cell provider doesn't have the feature turned on then the phone will recieve no GPS information.
It is my understanding that it is supposed to be initially a part of the e911 services that the cell phone companies are supposed to have already rolled out (I think). There was much discussion of the GPS feature, search it out if you want more info.
mg
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It should theoretically be possible, but it hasn't been done yet.
The idea behind Assisted GPS is that the phone only has part of a GPS receiver onboard - Specifically, it has the RF frontend and a correlator, but no CPU with enough power to process the pseudoranges obtained from the correlator. AGPS relies on the towers having additional computational power to obtain a solution fix from pseudoranges sent from the phone to the tower.
Unlike most E911 phones, the 7135 has the CPU power to obtain a position fix if pseudorange data can be obtained.
The problem is figuring out where that pseudorange data is stored in memory and/or what peripheral port addresses the correlator is sitting on. Once the pseudoranges are found, it should be possible to write an app that performs the necessary calculations. It's been done on a handful of phones already. (I can't remember which phone it was, I think it was one particular Motorola model.)
(Just to clarify - I'm 99% positive that there is no direct way to obtain a position fix, i.e. lat/long - a program would have to be written to calculate the position based on raw pseudorange data.)
Thanks for the link. That demo certainly makes it seem like the technology allows for the phone to initiate a GPS request on its own, not just at the call center. So it seems like it should be possible to take advantage of this in a palm app, all we need to do is figure out how to access the gpsone chip within the palm address space.
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