Ehsan Nourbakhsh’s Blog

Google Maps mobile has been one of my favorite applications from Google. Recently they added one beta feature to it which is a milestone for the Google Maps Mobile (GMM). They have added the ability to find your approximate geographical location solely based on the data that your cell phone receives from base stations. This is really nice since once you know the approximate location, you can guess the details yourself. Also, each time you don’t need to enter your own address before searching for the destination address.

It has been an interesting case to find out how they do it, and by how I mean the general implementation idea and not the theoretical foundations. I post here my current understanding of the implementation, which may be lacking some parts. I hope I can update this as I gather more information. (more…)

I am using a set of iPaq devices for some of my experiments here in UTD Distributed Systems lab. One of the devices is running WindowsCE 2003, the rest are running Familiar Distribution Linux. The WinCE one is collecting data about available wireless networks using mini-Netstumbler. The data gathered is not precise, but at the moment I only need only a general idea.

There have been a couple of problems about using the devices, which I will try to document here from now on. The first thing to note is about mini-Netstumbler. Netstumbler is “a tool for Windows that facilitates detection of Wireless LANs using the 802.11b, 802.11a and 802.11g WLAN standards”. In general Netstumbler needs a compatible device to be able to report noise levels. I was lucky to have an old SanDisk CompactFlash WiFi card which is able to report noise level.

I used a converter to connect the CompactFlash WiFi card to my notebook using the PCMCIA slot. Netstumbler under Windows XP was able to use this card without any other change. Below is a screenshot of Netstumbler.

Running miniNetstumbler needed one extra step. If you do not know this you may easily waste some hours. I had to to go to network settings, and add a wireless network setting with ESSID “ANY“, without encryption. Then connected to this “network” and ran miniNetstumbler. If you do not use the “ANY” network, you will see only statistics of the network you are connected to and not other networks.

I will try to post more about these later.

UPDATE: The list of compatible devices provided by NetStumbler is *not* updated. I got a Linksys WUSBGV4 through the link in www.stumbler.com/compat but it does not work with NetStumbler.