IPhone 4S has GLONASS in addition to GPS

Post by 0x12 » Wed, Oct 19, 2011, 1:38 PM UTC

jstclair wrote: post #30

0x12 wrote: post #29

Earlier quoted context omitted.

I don't understand from your table how the combined use of GPS+GLONASS would have a worse 'best case', 2.00 for GPS alone vs 2.37 for GPS+GLONASS.

I would imagine for the same reason as wearing two watches doesn't improve your knowledge of the current time. You're more likely to be within the largest margin of error (i.e., the latest time on either of the watches is probably no later than the current time), but what can you say about the earliest time? Since it's equally likely to be correct on either watch, the only thing you can do is average it. But in the c…

Post by zb » Wed, Oct 19, 2011, 1:43 PM UTC

flipbrad wrote: post #15

dchest wrote: post #2

Precisions: * GPS: 2.00—8.76 m * GLONASS: 4.46—7.38 m * GPS+GLONASS: 2.37—4.65 m [citation needed] (source: http://en.wikipedia.org/wiki/GLONASS ).

I'm wondering whether it actually matters to people whether their GPS device has 2, 4 or 7m accuracy. Anything with lower resolution than about 5 cm is going to be largely useless for robotic driving, etc, particularly anything worse than 2 m res - so really (and not meaning to be rude to you and your research efforts) - isn't the different resolution irrelevant, and isn't the only reason GPS users should be happy ab…

Post by Alex3917 » Wed, Oct 19, 2011, 1:54 PM UTC

0x12 wrote: post #31

jstclair wrote: post #30

Earlier quoted context omitted.

I would imagine for the same reason as wearing two watches doesn't improve your knowledge of the current time. You're more likely to be within the largest margin of error (i.e., the latest time on either of the watches is probably no later than the current time), but what can you say about the earliest time? Since it's equally likely to be correct on either watch, the only thing you can do is average it. But in the c…

So, if I understand you correctly, the average error decreases but the best error actually increases?

Post by Symmetry » Wed, Oct 19, 2011, 2:14 PM UTC

jstclair wrote: post #30

0x12 wrote: post #29

Earlier quoted context omitted.

I don't understand from your table how the combined use of GPS+GLONASS would have a worse 'best case', 2.00 for GPS alone vs 2.37 for GPS+GLONASS.

I would imagine for the same reason as wearing two watches doesn't improve your knowledge of the current time. You're more likely to be within the largest margin of error (i.e., the latest time on either of the watches is probably no later than the current time), but what can you say about the earliest time? Since it's equally likely to be correct on either watch, the only thing you can do is average it. But in the c…

Post by LiveTheDream » Wed, Oct 19, 2011, 2:22 PM UTC

lhnn wrote: post #34

I don't see a reference to GLONASS in the sub's page. Edit: It angers me that high-ranking users abuse their priviledge to downvote. I'm making a legitimate point here; I don't see "GLONASS" or any reference to alternative GPS in that page. On Reddit, someone suggested that TIL links to Wikipedia should point to the specific information, not the whole article. It got >1000 upvotes. When I point out that there is no o…