This week my HTC Desire registered me as being located in Warwickshire, England which was very strange because at the time I was at work in Londonderry, Northern Ireland. I actually didn’t notice until my dad sent me a text asking why I was showing up as being in England (my location is shared with him using Google Latitude) – he had actually thought my phone had been stolen when it wasn’t.

The location service had worked correctly at work many times before and it worked on the way home that evening and indeed when I got home it registered my location correctly. The next day when I got to work the same thing happened, although I noticed that it had not acquired a GPS lock. I tried to replicate the situation on my colleague’s HTC Desire but his showed the location correctly even without a GPS lock. The difference between our phones is that his is locked to Vodafone and running 2.1 Eclair, whereas mine is a SIM free unlocked handset running 2.2. Froyo on O2. Our location settings matched exactly. Had something in the Froyo update upset my location settings?

I looked closer at where the device supposedly said I was and to my shock it had me pinpointed to an office location our business had previously leased. This was a vital clue as it would have been a significant coincidence for my device to randomly pinpoint me there. There was no mention of that address in any of my contacts nor had the phone been at that location previously. The location system on the device appeared to be making a link between my work address and this other address that had been previously used by the business – this was puzzling and I was a little perplexed as to how it could be making this link when the other address was not widely known nor did it appear on the company website.

I tried some alternative settings and noted that when my wireless was turned off and when I got a GPS lock the location displayed correctly. The incorrect location was only set when I connected to the company’s guest WiFi network. Upon further investigation I discovered that the BT Business Hub to which I was connected had previously been used at the old address. I connected to the Hub and tried to find any settings in it for specifying where the router was located – I couldn’t find any. Either the location for the router is set within the device and cannot be edited or perhaps more likely a web service is being queried which uses the delivery address each router was despatched to as the location in which it is used. However this is just me speculating – if anyone knows anything more about what is going on perhaps they would share their knowledge by leaving a comment.

In conclusion, the HTC Desire is determining my location based on information supplied about the location of the wireless network it is connected to – which is not that surprising as the option in Location setting suggests that will happen anyway  – however in my case was inaccurate. This didn’t happen in Eclair so it appears that Froyo has been updated to use wireless network location information more effectively.

This raises some interesting issues in terms of the reliability and accuracy of location based services and how they can be exploited or raise trust issues when GPS is not available. For example if residential Home Hubs are affected in the same way there could be a lot of people registered as being in another house when they are actually in their own (i.e. in event the router was sold on) -  imagine the scenario if your friends and family see you staying overnight in another house using Google latitude – or alternatively if you want to appear somewhere you are not could you potentially take your router and set it up elsewhere masking your true location (or of course you could just stop using Latitude!).

I’m sure there are many wireless networks with inaccurate location information but I couldn’t find any other similar stories online. If you have any leave a comment…