How can we improve GPS performance?

The gear needed for wardriving

26 posts • Page 2 of 2

Postby argh » Mon Jan 07, 2008 2:25 pm

As per the first sentence of this thread, the problem wasn't accuracy, the problem was GPS not correlating location with some APs at all. Looking through the stats, I have 10,000 APs that I found, but have no location for. Looking up through the stats, this seems to be a common problem for many.

Since then, I replaced the Little Yellow Garmin (tm) with a USB Sirf III chipset GPS, and on two short drives, so far of about a thousand APs, I have them 100% now. Perhaps the problem was just fixed by better technology? Time will tell.

Postby littledave » Mon Jan 07, 2008 2:52 pm

As per the first sentence of this thread, the problem wasn't accuracy, the problem was GPS not correlating location with some APs at all. Looking through the stats, I have 10,000 APs that I found, but have no location for. Looking up through the stats, this seems to be a common problem for many.

Since then, I replaced the Little Yellow Garmin (tm) with a USB Sirf III chipset GPS, and on two short drives, so far of about a thousand APs, I have them 100% now. Perhaps the problem was just fixed by better technology? Time will tell.
Same version Gpsd/Kismet?

Postby argh » Mon Jan 07, 2008 3:29 pm

GPSD/KIsmet have been updated serveral times over the years, but for the last several months, they have remained the same versions. It might be interesting to run two instances of Kismet, one on the older serial GPS and one on the newer USB GPS to compare. Um, nah. As long as I keep dropping zero AP locations, I'll assume it's all better.

Postby argh » Mon Jan 07, 2008 3:29 pm

oops, double post.

Postby dagaroth » Sun Jan 27, 2008 5:33 am

This is a couple months old, but;
If you're driving down a road charting wireless, it's not going to make any difference how accurate your GPS is. You're on the road. The only way to get accurate is to drive up each and every driveway you think was a hit.
That's pretty much what I do. To get better readings, I usually just drive on the sidewalks and through people's yards. If you can't ring the door bell without getting out of your car, you're not close enough.
HAHAH!

Also, like someone else here said, if you're running one of those 5 foot 15dbi antennas, and a receive pre-amp, you're going to be picking up a large amount of AP's that may be a few streets over. Those data points, unless you hit those streets and get a "louder" signal will be skewed in the wrong direction.

Postby Dr_Dropper » Sat Mar 01, 2008 4:43 am

one thing that i do to improve the accuracy of the location of the AP's and how many AP's i find is to use two gps receivers on one computer and two different wireless cards. ive found that often times when i have two wireless adapters connected i will find X amount of AP's using prism 2 mode from the device selection and then i will find other AP's using the NDIS 5.1 setting. so i will open netstumbler two times and choose a different device and different gps com port for each one that way they can kinda cover each others asses if one misses something often times the other one will pick it up.

Postby Dr_Dropper » Sat Mar 01, 2008 4:44 am

EDIT: double post sorry.

Postby AxlMyk » Sat Mar 01, 2008 12:27 pm

Using 2 wireless cards has nothing to do with GPS accuracy. As you stated, one may pickup APs A,B,D,G,H and the other picks up C,E,F,I. How does that improve GPS accuracy? You are at point A, so is the GPS unit.

Postby Dr_Dropper » Sat Mar 01, 2008 5:31 pm

Using 2 wireless cards has nothing to do with GPS accuracy. As you stated, one may pickup APs A,B,D,G,H and the other picks up C,E,F,I. How does that improve GPS accuracy? You are at point A, so is the GPS unit.
right using two wireless cards does not improve gps accuracy but using two gps receivers does. that way if one gps receiver loses position lock the other one will still pickup the location.

Postby Dutch » Sat Mar 01, 2008 8:54 pm

Using 2 wireless cards has nothing to do with GPS accuracy. As you stated, one may pickup APs A,B,D,G,H and the other picks up C,E,F,I. How does that improve GPS accuracy? You are at point A, so is the GPS unit.
right using two wireless cards does not improve gps accuracy but using two gps receivers does. that way if one gps receiver loses position lock the other one will still pickup the location.
OK, so if you have two GPS recievers of the same make, or utilizing the same chipset, such as the SiRF-3 chipset, why do you think that only one of them will lose satelitte lock, while the other one won't ? They are afterall in the same vehicle, and probably quite close to each other, and both of them exposed to the same conditions with regards to being able to recieve the signals from the GPS satelittes.
If you are thinking hardware problems, just configure your setup to notify you if there is a loss of satelitte lock. Kismet has specific configuration options for just that case, and you can do the same with Network Stumbler.

Dutch

Dutch

Postby Dr_Dropper » Sun Mar 02, 2008 9:16 pm

Using 2 wireless cards has nothing to do with GPS accuracy. As you stated, one may pickup APs A,B,D,G,H and the other picks up C,E,F,I. How does that improve GPS accuracy? You are at point A, so is the GPS unit.
right using two wireless cards does not improve gps accuracy but using two gps receivers does. that way if one gps receiver loses position lock the other one will still pickup the location.
OK, so if you have two GPS recievers of the same make, or utilizing the same chipset, such as the SiRF-3 chipset, why do you think that only one of them will lose satelitte lock, while the other one won't ? They are afterall in the same vehicle, and probably quite close to each other, and both of them exposed to the same conditions with regards to being able to recieve the signals from the GPS satelittes.
If you are thinking hardware problems, just configure your setup to notify you if there is a loss of satelitte lock. Kismet has specific configuration options for just that case, and you can do the same with Network Stumbler.

Dutch

Dutch
who said anything about using two of the exact same gps receivers? i have 4 different kinds. and its not that i "think" one would lose the signal and one wouldnt, its that i see it happen every so often.

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