Thread: Comparing built-in GPS with Holux M1000
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ag2 is offline ag2
2008-01-04 , 18:54
Posts: 164 | Thanked: 132 times | Joined on Dec 2007
#9
Originally Posted by tz1 View Post
I have a Globaltop and it seems to work as well as the Holux (but at 5Hz!).

I'm not sure the times don't represent the lower sensitivity. Open any external GPS and you will find a 2cm x 2cm x 3-4mm strip antenna. Try removing that and see how fast it gets a fix. You can't put that into a tablet.

You could put the MTK chip in, but it would eat even more power (and mapping programs also tend to eat the battery), and it might perform worse without a good antenna.

There are GPS repeaters, and I wonder how fast the TI would get a fix if one of these were used.

I consider it a nice backup GPS, but if you are going to use it seriously, there are very inexpensive bluetooth devices (the GTop 5Hz base model is $50, and for $20 more you can get an ultrathin model - buygpsnow.com has them - and a HUD version).
The biggest advantage of MTK-based receivers is that they can track 30+ satellites simultaneously. This is what's responsible for 30 second cold starts -- the unit doesn't need to know where in the world it is, as it can track all (or most) satellites simultaneously. The N810 chipset can only do 12 satellites. So it needs to try the first 12 satellites, then try another 12 if the first 12 don't result in a fix, etc.

As I mentioned before, it appears that N810 does cold starts more often than is necessary (e.g. after a 10 minute period of inactivity). Has anyone noticed that the satellite status page of the map program rarely knows what satellites should be visible before a fix is aquired? It's almost as if it ignores available ephemeris/almanac data. In contrast, my 4-year old Garmin can plot visible satellites even after it's been off for a couple of weeks.
Last edited by ag2; 2008-01-05 at 01:30.