[Captivate Android Development] Rred:
az-

" Most of the time gps loc and accy circle of 10-15 meters will be at a location 3-4 house down the street and bouncing by 10 meters with each update."

Yes and no. "Bouncing" is the gps performance, but the position being off by 3-4 houses is the geocoding error. The translation of "street address" to "earthly position" is inaccurate. The amount of inaccuracy varies with the vendor and the local mapping, but it is almost always inaccurate, and if it gets within 1/2 mile that's all you can expect in some places. Getting within 100' is really "Wow, the dog talks!" mainly because correcting geocoding with exception tables is a damned expensive process that today's cheap vendors just aren't doing. (Navteq, Google, Garmin, any and all of them.) ESRI used to do it for their professional products but that's a whole other world.

"Now when you are driving the gps is much more accurate " or does it just give the delusion of accuracy, since it is know ignoring all data that isn't on the *road* and that extra filter is changing the results you see? If you drove down the wrong side of a divided highway, would it still show you on the right side? (But officer, honest, I'm not drunk I'm just testing the GPS!<G>)

"So my theroy is" Pretty good idea, that would be a way to keep the CPU load from the GPS lower. Maybe "Android 4.0" will allow us to set task priorities on the different tasks, huh?

"Your GPS location is determined solely by the amount of time it takes the ping from the sats to reach your device. The device then takes at least 3 different sat pings and converts that timing data to lat,lon,elev,speed,etc.. Every ~10mins it sends an update signal to the gps receiver so it can sync the clocks." Yes, but to pick nit it needs 3 satellites to get a 2D fix and 4 to get a 3D fix and anything more is just refinement of the position. Some really clever vendor one day is going to let us get a fix from just 2 satellites, since that resolves down to 'You're either here or here" and one certainly hopes the average user knows which of those two locations they are in, usually thousands of miles apart from each other.<G> The extra periodic signal isn't just for setting the clocks (although the clock jumps once it processes that) the system also carries epehmeris and almanac resets on a periodic basis, which help with accuracy on the location calculations.

"I love this phone but it couldn't track a M1A1 tank if it was glued to it!!" Cell phones and heavy armor...there's just GOTTA be a new episode of Top Gear that could be based on that. Mythbusters, at least!

There are--very seriously--questions about "foreign" sourced chips and CPUs and embedded code with cyberwar purposes. Some supposedly confirmed by the DoD. A good case could be made for a legal requirement that all code in all of these chips be examined, confirmed, and explained by an objective source, before they were allowed on the market. One side effect of which would be that folks like Samsung would have a much harder time stonewalling about what the product was, or wasn't, really doing.

(Consider, if North Korea planted an engineer across the border at Samsung. Easy. And that engineer wrote GPS coding that made all the chips go belly-up on command. Ooopsie, that could easily happen. Except, of course, these chips are supplied by Broadcom, not Samsung, so the intermediate code would have to be the question.)