Satellite Curiosity

[ElectricBoss]

Hi all. I have noticed something I was hoping the big gps brains could explain to me. I have messed around with gps over the years for navigation & have had satellite radio for about 7 years. I have always lost my satellite signal in the normal places, tunnels, car washes, enclosed garages, etc. But, over the last couple years I have noticed a change. Everything now works in those places, within reason of course. For instance I went to an event at our convention center. I parked in the enclosed concrete parking structure. I pulled inside about 150’-200’ to park & my satellite radio never skipped a beat. Also I noticed a while back my satellite radio kept playing inside the touchless automatic car wash I go to. This morning while in the car wash I tried Google Maps & it marked my location just fine. The only thing my small brain can figure is they put satellites low on the horizon or fit them with x-ray glasses. Just wondering if anyone knew what changed. Thanks.

[w00dy65]

I don't think that the GPS you're using to Google is really extra-terrestrially (satellite) received to your phone. I hope that makes more sense that it looks...bare with me, I'm on my first shot of coffee!

Anyway....

What your phone is receiving and transmitting is real time data received from a cell tower (probably more than one)...and that's where the terrestrial or low horizon issue comes into play.

If you climb Mt. Whitney, for example, to the point of absolutely NO CELL SERVICE at none...your phone would not be able to be used as a GPS device, like a Magellan would.....however, you're XM radio from the heavens would be clear a day!

I'm no GPS brain, but that's the way I understand how it works...as for XM's coverage inside of a structure, I wouldn't spread that around too much...it may effect your bill.

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[chrisy520]

XM Sirius use repeaters to bounce the signal around when there is not direct line of sight (especially in cities with tall buildings).

i get better Sirius coverage inside an apartment building in Nashville (near a window) then i get outside in my yard in my small town.

i've had Sirius for over 4 years and i'm noticing better and better coverage. i attribute this to them putting up more repeaters. But that's just a guess.

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[w00dy65]

That would explain it!!!

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[BruceRTL]

Originally Posted by w00dy65

I don't think that the GPS you're using to Google is really extra-terrestrially (satellite) received to your phone. I hope that makes more sense that it looks...bare with me, I'm on my first shot of coffee!

Anyway....

What your phone is receiving and transmitting is real time data received from a cell tower (probably more than one)...and that's where the terrestrial or low horizon issue comes into play.

If you climb Mt. Whitney, for example, to the point of absolutely NO CELL SERVICE at none...your phone would not be able to be used as a GPS device, like a Magellan would.....however, you're XM radio from the heavens would be clear a day!

I'm no GPS brain, but that's the way I understand how it works...as for XM's coverage inside of a structure, I wouldn't spread that around too much...it may effect your bill.

Posted from my CrackBerry at wapforums.crackberry.com

I disagree!

Google Maps requires an internet connection to download maps, not to determine your location. Your GPS talks directly to the satellites just like a hand held Garmin does. To prove that, turn off the cell phone connection, under Manage Connections on your BB and then see what Google Maps shows you. I'm sure you will see a map or aerial view because Google caches the images but if you refresh the screen all you will see is the blue flashing dot indicating your position. That's the GPS still working even though your BB is not talking to the cell towers.

Don't forget to turn the cell phone connection back on!